essay on exchange of gases

22.4 Gas Exchange

Learning objectives.

By the end of this section, you will be able to:

Compare the composition of atmospheric air and alveolar air
Describe the mechanisms that drive gas exchange
Discuss the importance of sufficient ventilation and perfusion, and how the body adapts when they are insufficient
Discuss the process of external respiration
Describe the process of internal respiration

The purpose of the respiratory system is to perform gas exchange. Pulmonary ventilation provides air to the alveoli for this gas exchange process. At the respiratory membrane, where the alveolar and capillary walls meet, gases move across the membranes, with oxygen entering the bloodstream and carbon dioxide exiting. It is through this mechanism that blood is oxygenated and carbon dioxide, the waste product of cellular respiration, is removed from the body.

Gas Exchange

In order to understand the mechanisms of gas exchange in the lung, it is important to understand the underlying principles of gases and their behavior. In addition to Boyle’s law, several other gas laws help to describe the behavior of gases.

Gas Laws and Air Composition

Gas molecules exert force on the surfaces with which they are in contact; this force is called pressure. In natural systems, gases are normally present as a mixture of different types of molecules. For example, the atmosphere consists of oxygen, nitrogen, carbon dioxide, and other gaseous molecules, and this gaseous mixture exerts a certain pressure referred to as atmospheric pressure ( Table 22.2 ). Partial pressure ( P x ) is the pressure of a single type of gas in a mixture of gases. For example, in the atmosphere, oxygen exerts a partial pressure, and nitrogen exerts another partial pressure, independent of the partial pressure of oxygen ( Figure 22.4.1 ). Total pressure is the sum of all the partial pressures of a gaseous mixture. Dalton’s law describes the behavior of nonreactive gases in a gaseous mixture and states that a specific gas type in a mixture exerts its own pressure; thus, the total pressure exerted by a mixture of gases is the sum of the partial pressures of the gases in the mixture.

The left panel of this figure shows a canister of oxygen. The middle panel shows a canister of nitrogen. The right panel shows a canister containing a mixture of oxygen and nitrogen. A pressure gauge on each container shows the pressure exerted by the gas in that container.

Partial pressure is extremely important in predicting the movement of gases. Recall that gases tend to equalize their pressure in two regions that are connected. A gas will move from an area where its partial pressure is higher to an area where its partial pressure is lower. In addition, the greater the partial pressure difference between the two areas, the more rapid is the movement of gases.

Solubility of Gases in Liquids

Henry’s law describes the behavior of gases when they come into contact with a liquid, such as blood. Henry’s law states that the concentration of gas in a liquid is directly proportional to the solubility and partial pressure of that gas. The greater the partial pressure of the gas, the greater the number of gas molecules that will dissolve in the liquid. The concentration of the gas in a liquid is also dependent on the solubility of the gas in the liquid. For example, although nitrogen is present in the atmosphere, very little nitrogen dissolves into the blood, because the solubility of nitrogen in blood is very low. The exception to this occurs in scuba divers; the composition of the compressed air that divers breathe causes nitrogen to have a higher partial pressure than normal, causing it to dissolve in the blood in greater amounts than normal. Too much nitrogen in the bloodstream results in a serious condition that can be fatal if not corrected. Gas molecules establish an equilibrium between those molecules dissolved in liquid and those in air.

The composition of air in the atmosphere and in the alveoli differs. In both cases, the relative concentration of gases is nitrogen > oxygen > water vapor > carbon dioxide. The amount of water vapor present in alveolar air is greater than that in atmospheric air ( Table 22.3 ). Recall that the respiratory system works to humidify incoming air, thereby causing the air present in the alveoli to have a greater amount of water vapor than atmospheric air. In addition, alveolar air contains a greater amount of carbon dioxide and less oxygen than atmospheric air. This is no surprise, as gas exchange removes oxygen from and adds carbon dioxide to alveolar air. Both deep and forced breathing cause the alveolar air composition to be changed more rapidly than during quiet breathing. As a result, the partial pressures of oxygen and carbon dioxide change, affecting the diffusion process that moves these materials across the membrane. This will cause oxygen to enter and carbon dioxide to leave the blood more quickly.

Ventilation and Perfusion

Two important aspects of gas exchange in the lung are ventilation and perfusion. Ventilation is the movement of air into and out of the lungs, and perfusion is the flow of blood in the pulmonary capillaries. For gas exchange to be efficient, the volumes involved in ventilation and perfusion should be compatible. However, factors such as regional gravity effects on blood, blocked alveolar ducts, or disease can cause ventilation and perfusion to be imbalanced.

The partial pressure of oxygen in alveolar air is about 104 mm Hg, whereas the partial pressure of the oxygenated pulmonary venous blood is about 100 mm Hg. When ventilation is sufficient, oxygen enters the alveoli at a high rate, and the partial pressure of oxygen in the alveoli remains high. In contrast, when ventilation is insufficient, the partial pressure of oxygen in the alveoli drops. Without the large difference in partial pressure between the alveoli and the blood, oxygen does not diffuse efficiently across the respiratory membrane. The body has mechanisms that counteract this problem. In cases when ventilation is not sufficient for an alveolus, the body redirects blood flow to alveoli that are receiving sufficient ventilation. This is achieved by constricting the pulmonary arterioles that serves the dysfunctional alveolus, which redirects blood to other alveoli that have sufficient ventilation. At the same time, the pulmonary arterioles that serve alveoli receiving sufficient ventilation vasodilate, which brings in greater blood flow. Factors such as carbon dioxide, oxygen, and pH levels can all serve as stimuli for adjusting blood flow in the capillary networks associated with the alveoli.

Ventilation is regulated by the diameter of the airways, whereas perfusion is regulated by the diameter of the blood vessels. The diameter of the bronchioles is sensitive to the partial pressure of carbon dioxide in the alveoli. A greater partial pressure of carbon dioxide in the alveoli causes the bronchioles to increase their diameter as will a decreased level of oxygen in the blood supply, allowing carbon dioxide to be exhaled from the body at a greater rate. As mentioned above, a greater partial pressure of oxygen in the alveoli causes the pulmonary arterioles to dilate, increasing blood flow.

Gas exchange occurs at two sites in the body: in the lungs, where oxygen is picked up and carbon dioxide is released at the respiratory membrane, and at the tissues, where oxygen is released and carbon dioxide is picked up. External respiration is the exchange of gases with the external environment, and occurs in the alveoli of the lungs. Internal respiration is the exchange of gases with the internal environment, and occurs in the tissues. The actual exchange of gases occurs due to simple diffusion. Energy is not required to move oxygen or carbon dioxide across membranes. Instead, these gases follow pressure gradients that allow them to diffuse. The anatomy of the lung maximizes the diffusion of gases: The respiratory membrane is highly permeable to gases; the respiratory and blood capillary membranes are very thin; and there is a large surface area throughout the lungs.

External Respiration

The pulmonary artery carries deoxygenated blood into the lungs from the heart, where it branches and eventually becomes the capillary network composed of pulmonary capillaries. These pulmonary capillaries create the respiratory membrane with the alveoli ( Figure 22.4.2 ). As the blood is pumped through this capillary network, gas exchange occurs. Although a small amount of the oxygen is able to dissolve directly into plasma from the alveoli, most of the oxygen is picked up by erythrocytes (red blood cells) and binds to a protein called hemoglobin, a process described later in this chapter. Oxygenated hemoglobin is red, causing the overall appearance of bright red oxygenated blood, which returns to the heart through the pulmonary veins. Carbon dioxide is released in the opposite direction of oxygen, from the blood to the alveoli. Some of the carbon dioxide is returned on hemoglobin, but can also be dissolved in plasma or is present as a converted form, also explained in greater detail later in this chapter.

External respiration occurs as a function of partial pressure differences in oxygen and carbon dioxide between the alveoli and the blood in the pulmonary capillaries.

This figure shows the pathway in which external respiration takes place. The exchange of oxygen and carbon dioxide between the alveolus and blood plasma is detailed.

Although the solubility of oxygen in blood is not high, there is a drastic difference in the partial pressure of oxygen in the alveoli versus in the blood of the pulmonary capillaries. This difference is about 64 mm Hg: The partial pressure of oxygen in the alveoli is about 104 mm Hg, whereas its partial pressure in the blood of the capillary is about 40 mm Hg. This large difference in partial pressure creates a very strong pressure gradient that causes oxygen to rapidly cross the respiratory membrane from the alveoli into the blood.

The partial pressure of carbon dioxide is also different between the alveolar air and the blood of the capillary. However, the partial pressure difference is less than that of oxygen, about 5 mm Hg. The partial pressure of carbon dioxide in the blood of the capillary is about 45 mm Hg, whereas its partial pressure in the alveoli is about 40 mm Hg. However, the solubility of carbon dioxide is much greater than that of oxygen—by a factor of about 20—in both blood and alveolar fluids. As a result, the relative concentrations of oxygen and carbon dioxide that diffuse across the respiratory membrane are similar.

Internal Respiration

Internal respiration is gas exchange that occurs at the level of body tissues ( Figure 22.4.3 ). Similar to external respiration, internal respiration also occurs as simple diffusion due to a partial pressure gradient. However, the partial pressure gradients are opposite of those present at the respiratory membrane. The partial pressure of oxygen in tissues is low, about 40 mm Hg, because oxygen is continuously used for cellular respiration. In contrast, the partial pressure of oxygen in the blood is about 100 mm Hg. This creates a pressure gradient that causes oxygen to dissociate from hemoglobin, diffuse out of the blood, cross the interstitial space, and enter the tissue. Hemoglobin that has little oxygen bound to it loses much of its brightness, so that blood returning to the heart is more burgundy in color.

Considering that cellular respiration continuously produces carbon dioxide, the partial pressure of carbon dioxide is lower in the blood than it is in the tissue, causing carbon dioxide to diffuse out of the tissue, cross the interstitial fluid, and enter the blood. It is then carried back to the lungs either bound to hemoglobin, dissolved in plasma, or in a converted form. By the time blood returns to the heart, the partial pressure of oxygen has returned to about 40 mm Hg, and the partial pressure of carbon dioxide has returned to about 45 mm Hg. The blood is then pumped back to the lungs to be oxygenated once again during external respiration.

This diagram details the pathway of internal respiration. The exchange of oxygen and carbon dioxide between a red blood cell and a tissue cell is shown.

Everyday Connection – Hyperbaric Chamber Treatment

A type of device used in some areas of medicine that exploits the behavior of gases is hyperbaric chamber treatment. A hyperbaric chamber is a unit that can be sealed and expose a patient to either 100 percent oxygen with increased pressure or a mixture of gases that includes a higher concentration of oxygen than normal atmospheric air, also at a higher partial pressure than the atmosphere. There are two major types of chambers: monoplace and multiplace. Monoplace chambers are typically for one patient, and the staff tending to the patient observes the patient from outside of the chamber ( Figure 22.4.4 ). Some facilities have special monoplace hyperbaric chambers that allow multiple patients to be treated at once, usually in a sitting or reclining position, to help ease feelings of isolation or claustrophobia. Multiplace chambers are large enough for multiple patients to be treated at one time, and the staff attending these patients is present inside the chamber. In a multiplace chamber, patients are often treated with air via a mask or hood, and the chamber is pressurized.

This photo shows two hyperbaric chambers.

Hyperbaric chamber treatment is based on the behavior of gases. As you recall, gases move from a region of higher partial pressure to a region of lower partial pressure. In a hyperbaric chamber, the atmospheric pressure is increased, causing a greater amount of oxygen than normal to diffuse into the bloodstream of the patient. Hyperbaric chamber therapy is used to treat a variety of medical problems, such as wound and graft healing, anaerobic bacterial infections, and carbon monoxide poisoning. Exposure to and poisoning by carbon monoxide is difficult to reverse, because hemoglobin’s affinity for carbon monoxide is much stronger than its affinity for oxygen, causing carbon monoxide to replace oxygen in the blood. Hyperbaric chamber therapy can treat carbon monoxide poisoning, because the increased atmospheric pressure causes more oxygen to diffuse into the bloodstream. At this increased pressure and increased concentration of oxygen, carbon monoxide is displaced from hemoglobin. Another example is the treatment of anaerobic bacterial infections, which are created by bacteria that cannot or prefer not to live in the presence of oxygen. An increase in blood and tissue levels of oxygen helps to kill the anaerobic bacteria that are responsible for the infection, as oxygen is toxic to anaerobic bacteria. For wounds and grafts, the chamber stimulates the healing process by increasing energy production needed for repair. Increasing oxygen transport allows cells to ramp up cellular respiration and thus ATP production, the energy needed to build new structures.

Chapter Review

The behavior of gases can be explained by the principles of Dalton’s law and Henry’s law, both of which describe aspects of gas exchange. Dalton’s law states that each specific gas in a mixture of gases exerts force (its partial pressure) independently of the other gases in the mixture. Henry’s law states that the amount of a specific gas that dissolves in a liquid is a function of its partial pressure. The greater the partial pressure of a gas, the more of that gas will dissolve in a liquid, as the gas moves toward equilibrium. Gas molecules move down a pressure gradient; in other words, gas moves from a region of high pressure to a region of low pressure. The partial pressure of oxygen is high in the alveoli and low in the blood of the pulmonary capillaries. As a result, oxygen diffuses across the respiratory membrane from the alveoli into the blood. In contrast, the partial pressure of carbon dioxide is high in the pulmonary capillaries and low in the alveoli. Therefore, carbon dioxide diffuses across the respiratory membrane from the blood into the alveoli. The amount of oxygen and carbon dioxide that diffuses across the respiratory membrane is similar.

Ventilation is the process that moves air into and out of the alveoli, and perfusion affects the flow of blood in the capillaries. Both are important in gas exchange, as ventilation must be sufficient to create a high partial pressure of oxygen in the alveoli. If ventilation is insufficient and the partial pressure of oxygen drops in the alveolar air, the capillary is constricted and blood flow is redirected to alveoli with sufficient ventilation. External respiration refers to gas exchange that occurs in the alveoli, whereas internal respiration refers to gas exchange that occurs in the tissue. Both are driven by partial pressure differences.

Review Questions

Critical thinking questions.

1. Compare and contrast Dalton’s law and Henry’s law.

2. A smoker develops damage to several alveoli that then can no longer function. How does this affect gas exchange?

Answers for Critical Thinking Questions

Both Dalton’s and Henry’s laws describe the behavior of gases. Dalton’s law states that any gas in a mixture of gases exerts force as if it were not in a mixture. Henry’s law states that gas molecules dissolve in a liquid proportional to their partial pressure.
The damaged alveoli will have insufficient ventilation, causing the partial pressure of oxygen in the alveoli to decrease. As a result, the pulmonary capillaries serving these alveoli will constrict, redirecting blood flow to other alveoli that are receiving sufficient ventilation.

This work, Anatomy & Physiology, is adapted from Anatomy & Physiology by OpenStax , licensed under CC BY . This edition, with revised content and artwork, is licensed under CC BY-SA except where otherwise noted.

Images, from Anatomy & Physiology by OpenStax , are licensed under CC BY except where otherwise noted.

Access the original for free at https://openstax.org/books/anatomy-and-physiology/pages/1-introduction .

Anatomy & Physiology Copyright © 2019 by Lindsay M. Biga, Staci Bronson, Sierra Dawson, Amy Harwell, Robin Hopkins, Joel Kaufmann, Mike LeMaster, Philip Matern, Katie Morrison-Graham, Kristen Oja, Devon Quick, Jon Runyeon, OSU OERU, and OpenStax is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License , except where otherwise noted.

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116 13.1 Case Study: Respiratory System and Gas Exchange

Created by CK-12 Foundation/Adapted by Christine Miller

Case Study: Cough That Won’t Quit

Three weeks ago, 20-year-old Erica came down with symptoms typical of the common cold. She had a runny nose, fatigue, and a mild cough. Her symptoms were starting to improve, but recently, her cough has been getting worse. She is coughing up a lot of thick mucus, her throat is sore from frequent coughing, and her chest feels very congested. According to her grandmother, Erica has a “chest cold.” Erica is a smoker and wonders if her habit is making her cough worse. She decides that it’s time to see a doctor.

Dr. Choo examines Erica and asks about her symptoms and health history. She checks the level of oxygen in Erica’s blood by attaching a device called a pulse oximeter to Erica’s finger.

Dr. Choo concludes that Erica has bronchitis , which is an infection that commonly occurs after a person has a cold or flu. Bronchitis is sometimes referred to as a “chest cold,” so Erica’s grandmother was right! Bronchitis causes inflammation and a build up of mucus in the bronchial tubes in the chest.

Because bronchitis is usually caused by viruses and not bacteria , Dr. Choo tells Erica that antibiotics are not likely to help. Instead, she recommends that Erica try to thin out and remove the mucus by drinking plenty of fluids and using a humidifier or spending time in a steamy shower. She recommends that Erica get plenty of rest as well.

Dr. Choo also tells Erica some things not to do — most importantly, to stop smoking while she is sick, and to try to quit smoking in the long-term. She explains that smoking can make people more susceptible to bronchitis and can hinder recovery. Finally, she advises Erica to avoid taking over-the-counter cough suppressant medication.

As you read this chapter about the respiratory system, you will be able to better understand what bronchitis is, and why Dr. Choo made the treatment recommendations that she did. At the end of the chapter, you will learn more about acute bronchitis, which is the type that Erica has. This information may come in handy to you personally, because chances are high that you will get this common infection at some point in your life — there are millions of cases of bronchitis every year!

Chapter Overview: Respiratory System

In this chapter, you will learn about the respiratory system — the system that exchanges gases (such as oxygen and carbon dioxide) between the body and the outside air. Specifically, you will learn about:

The process of respiration, in which oxygen moves from the outside air into the body and carbon dioxide and other waste gases move from inside the body into the outside air.
The organs of the respiratory system, including the lungs, bronchial tubes, and the rest of the respiratory tract.
How the respiratory tract protects itself from pathogens and other potentially harmful substances in the air.
How the rate of breathing is regulated to maintain homeostasis of blood gases and pH.
How ventilation, or breathing, allows us to inhale air into the body and exhale air out of the body.
The conscious and unconscious control of breathing.
Nasal breathing compared to mouth breathing.
What happens when a person is drowning.
How gas exchange occurs between the air and blood in the alveoli of the lungs, and between the blood and cells throughout the body.
Disorders of the respiratory system, including asthma, pneumonia, chronic obstructive pulmonary disease (COPD), and lung cancer.
The negative health effects of smoking.

As you read the chapter, think about the following questions:

Where are the bronchial tubes? What is their function?
What is the function of mucus? Why can too much mucus be a bad thing?
Why did Dr. Choo check Erica’s blood oxygen level?
Why do you think Dr. Choo warned Erica to avoid cough suppressant medications?
How does acute bronchitis compare to chronic bronchitis? How do they both relate to smoking?

Attributions

Figure 13.1.1

Cold/ Look into my eyes forever [photo] by Spencer Backman on Unsplash is used under the Unsplash License (https://unsplash.com/license).

Figure 13.1.2

Wrist-oximeter by UusiAjaja on Wikimedia Commons is used under a CC0 1.0 Universal Public Domain Dedication (https://creativecommons.org/publicdomain/zero/1.0/deed.en) license.

Mayo Clinic Staff. (n.d.). Bronchitis [online article]. Mayoclinic.org. https://www.mayoclinic.org/diseases-conditions/bronchitis/symptoms-causes/syc-20355566

Inflammation of the mucous membrane in the bronchial tubes. It typically causes bronchospasm and coughing

A tiny, nonliving particle that contains nucleic acids but lacks other characteristics of living cells and may cause human disease.

Any member of a large group of unicellular microorganisms which have cell walls but lack organelles and an organized nucleus, including some which can cause disease.

The body system responsible for taking in oxygen and expelling carbon dioxide. The primary organs of the respiratory system are the lungs, which carry out this exchange of gases as we breathe.

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8.5: Gas Exchange

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Learning Objectives

By the end of this section, you will be able to:

Compare the composition of atmospheric air and alveolar air
Describe the mechanisms that drive gas exchange
Discuss the importance of sufficient ventilation and perfusion, and how the body adapts when they are insufficient
Discuss the process of external respiration
Describe the process of internal respiration

Gas Exchange

Gas Laws and Air Composition

Partial pressure ( P x ) is the pressure of a single type of gas in a mixture of gases. For example, in the atmosphere, oxygen exerts a partial pressure, and nitrogen exerts another partial pressure, independent of the partial pressure of oxygen (Figure 1). Total pressure is the sum of all the partial pressures of a gaseous mixture. Dalton’s law describes the behavior of nonreactive gases in a gaseous mixture and states that a specific gas type in a mixture exerts its own pressure; thus, the total pressure exerted by a mixture of gases is the sum of the partial pressures of the gases in the mixture.

Solubility of Gases in Liquids

The composition of air in the atmosphere and in the alveoli differs. In both cases, the relative concentration of gases is nitrogen > oxygen > water vapor > carbon dioxide. The amount of water vapor present in alveolar air is greater than that in atmospheric air (Table 2). Recall that the respiratory system works to humidify incoming air, thereby causing the air present in the alveoli to have a greater amount of water vapor than atmospheric air. In addition, alveolar air contains a greater amount of carbon dioxide and less oxygen than atmospheric air. This is no surprise, as gas exchange removes oxygen from and adds carbon dioxide to alveolar air. Both deep and forced breathing cause the alveolar air composition to be changed more rapidly than during quiet breathing. As a result, the partial pressures of oxygen and carbon dioxide change, affecting the diffusion process that moves these materials across the membrane. This will cause oxygen to enter and carbon dioxide to leave the blood more quickly.

Ventilation and Perfusion

External Respiration

The pulmonary artery carries deoxygenated blood into the lungs from the heart, where it branches and eventually becomes the capillary network composed of pulmonary capillaries. These pulmonary capillaries create the respiratory membrane with the alveoli. As the blood is pumped through this capillary network, gas exchange occurs. Although a small amount of the oxygen is able to dissolve directly into plasma from the alveoli, most of the oxygen is picked up by erythrocytes (red blood cells) and binds to a protein called hemoglobin, a process described later in this chapter. Oxygenated hemoglobin is red, causing the overall appearance of bright red oxygenated blood, which returns to the heart through the pulmonary veins. Carbon dioxide is released in the opposite direction of oxygen, from the blood to the alveoli. Some of the carbon dioxide is returned on hemoglobin, but can also be dissolved in plasma or is present as a converted form, also explained in greater detail later in this chapter.

External respiration occurs as a function of partial pressure differences in oxygen and carbon dioxide between the alveoli and the blood in the pulmonary capillaries.

Internal Respiration

Internal respiration is gas exchange that occurs at the level of body tissues (Figure 3). Similar to external respiration, internal respiration also occurs as simple diffusion due to a partial pressure gradient. However, the partial pressure gradients are opposite of those present at the respiratory membrane. The partial pressure of oxygen in tissues is low, about 40 mm Hg, because oxygen is continuously used for cellular respiration. In contrast, the partial pressure of oxygen in the blood is about 100 mm Hg. This creates a pressure gradient that causes oxygen to dissociate from hemoglobin, diffuse out of the blood, cross the interstitial space, and enter the tissue. Hemoglobin that has little oxygen bound to it loses much of its brightness, so that blood returning to the heart is more burgundy in color.

Everyday Connections: Hyperbaric Chamber Treatment

A type of device used in some areas of medicine that exploits the behavior of gases is hyperbaric chamber treatment. A hyperbaric chamber is a unit that can be sealed and expose a patient to either 100 percent oxygen with increased pressure or a mixture of gases that includes a higher concentration of oxygen than normal atmospheric air, also at a higher partial pressure than the atmosphere. There are two major types of chambers: monoplace and multiplace. Monoplace chambers are typically for one patient, and the staff tending to the patient observes the patient from outside of the chamber. Some facilities have special monoplace hyperbaric chambers that allow multiple patients to be treated at once, usually in a sitting or reclining position, to help ease feelings of isolation or claustrophobia. Multiplace chambers are large enough for multiple patients to be treated at one time, and the staff attending these patients is present inside the chamber. In a multiplace chamber, patients are often treated with air via a mask or hood, and the chamber is pressurized.

Chapter Review

Answer the question(s) below to see how well you understand the topics covered in the previous section.

https://oea.herokuapp.com/assessments/266

Critical Thinking Questions

Compare and contrast Dalton’s law and Henry’s law.
A smoker develops damage to several alveoli that then can no longer function. How does this affect gas exchange?

[reveal-answer q=”768033″]Show Answers[/reveal-answer] [hidden-answer a=”768033″]

Both Dalton’s and Henry’s laws describe the behavior of gases. Dalton’s law states that any gas in a mixture of gases exerts force as if it were not in a mixture. Henry’s law states that gas molecules dissolve in a liquid proportional to their partial pressure.
The damaged alveoli will have insufficient ventilation, causing the partial pressure of oxygen in the alveoli to decrease. As a result, the pulmonary capillaries serving these alveoli will constrict, redirecting blood flow to other alveoli that are receiving sufficient ventilation.

[/hidden-answer]

Dalton’s law: statement of the principle that a specific gas type in a mixture exerts its own pressure, as if that specific gas type was not part of a mixture of gases

external respiration: gas exchange that occurs in the alveoli

Henry’s law: statement of the principle that the concentration of gas in a liquid is directly proportional to the solubility and partial pressure of that gas

internal respiration: gas exchange that occurs at the level of body tissues

partial pressure: force exerted by each gas in a mixture of gases

total pressure: sum of all the partial pressures of a gaseous mixture

ventilation: movement of air into and out of the lungs; consists of inspiration and expiration

Contributors and Attributions

Anatomy & Physiology. Provided by : OpenStax CNX. Located at : http://cnx.org/contents/[email protected] . License : CC BY: Attribution . License Terms : Download for free at http://cnx.org/contents/[email protected]

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Unit 2: Breathing and exchange of gases

The respiratory system.

Circulatory & respiratory systems (Opens a modal)
Meet the lungs! (Opens a modal)
The lungs and pulmonary system (Opens a modal)
The bronchial tree (Opens a modal)
Pulmonary volume (Opens a modal)
The respiratory system Get 3 of 4 questions to level up!

Mechanism of breathing

How does lung volume change? (Opens a modal)
Inhaling and exhaling (Opens a modal)
Mechanism of breathing Get 3 of 4 questions to level up!

Exchange and transport of gases

Partial pressure and exchange of gases (Opens a modal)
Alveoli - site of gaseous exchange (Opens a modal)
Hemoglobin (Opens a modal)
Hemoglobin moves O2 and CO2 (Opens a modal)
Exchange of gases Get 3 of 4 questions to level up!
Transport of oxygen and carbon dioxide Get 6 of 8 questions to level up!

Regulation and disorders of respiration

The regulation of respiration (Opens a modal)
Asthma (Opens a modal)
Emphysema (Opens a modal)
Occupational respiratory disorders (Opens a modal)
The respiratory system review (Opens a modal)

Want to create or adapt books like this? Learn more about how Pressbooks supports open publishing practices.

13.1 Case Study: Respiratory System and Gas Exchange

Created by CK-12 Foundation/Adapted by Christine Miller

Case Study: Cough That Won’t Quit

Dr. Choo examines Erica and asks about her symptoms and health history. She checks the level of oxygen in Erica’s blood by attaching a device called a pulse oximeter to Erica’s finger.

Chapter Overview: Respiratory System

The process of respiration, in which oxygen moves from the outside air into the body and carbon dioxide and other waste gases move from inside the body into the outside air.
The organs of the respiratory system, including the lungs, bronchial tubes, and the rest of the respiratory tract.
How the respiratory tract protects itself from pathogens and other potentially harmful substances in the air.
How the rate of breathing is regulated to maintain homeostasis of blood gases and pH.
How ventilation, or breathing, allows us to inhale air into the body and exhale air out of the body.
The conscious and unconscious control of breathing.
Nasal breathing compared to mouth breathing.
What happens when a person is drowning.
How gas exchange occurs between the air and blood in the alveoli of the lungs, and between the blood and cells throughout the body.
Disorders of the respiratory system, including asthma, pneumonia, chronic obstructive pulmonary disease (COPD), and lung cancer.
The negative health effects of smoking.

As you read the chapter, think about the following questions:

Where are the bronchial tubes? What is their function?
What is the function of mucus? Why can too much mucus be a bad thing?
Why did Dr. Choo check Erica’s blood oxygen level?
Why do you think Dr. Choo warned Erica to avoid cough suppressant medications?
How does acute bronchitis compare to chronic bronchitis? How do they both relate to smoking?

Attributions

Figure 13.1.1

Cold/ Look into my eyes forever [photo] by Spencer Backman on Unsplash is used under the Unsplash License (https://unsplash.com/license).

Figure 13.1.2

Wrist-oximeter by UusiAjaja on Wikimedia Commons is used under a CC0 1.0 Universal Public Domain Dedication (https://creativecommons.org/publicdomain/zero/1.0/deed.en) license.

Mayo Clinic Staff. (n.d.). Bronchitis [online article]. Mayoclinic.org. https://www.mayoclinic.org/diseases-conditions/bronchitis/symptoms-causes/syc-20355566

Inflammation of the mucous membrane in the bronchial tubes. It typically causes bronchospasm and coughing

A tiny, nonliving particle that contains nucleic acids but lacks other characteristics of living cells and may cause human disease.

Any member of a large group of unicellular microorganisms which have cell walls but lack organelles and an organized nucleus, including some which can cause disease.

The body system responsible for taking in oxygen and expelling carbon dioxide. The primary organs of the respiratory system are the lungs, which carry out this exchange of gases as we breathe.

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3 Gas Exchange

Published: October 2023
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Inadequate gas exchange (respiratory failure) is the most common reason for admission to critical care and associated with high mortality rates. Effective gas exchange requires adequate ventilation, diffusion, and perfusion. Hypoxaemia (low blood oxygen saturation) will result if any of these are inadequate, whereas hypercapnia typically results from inadequate ventilation. Two different types of respiratory failure can be considered clinically—normocapnic (sometimes called ‘Type 1’), where oxygenation is impaired but ventilation and therefore clearance of carbon dioxide (CO 2 ) is not, and hypercapnic (‘Type 2’), where inadequate ventilation impairs CO 2 clearance as well as oxygenation. In physiological terms—and regardless of the underlying disease process—hypoxaemia always results from one of five possible causes: less inspired oxygen (e.g. high altitude), hypoventilation, impaired diffusion across the alveolar membrane, inequality of ventilation and perfusion (‘ V / Q mismatch’), and shunting (blood flow that does not participate in gas exchange). Increasing the inspired oxygen may seem the obvious treatment for respiratory failure; however, unnecessary hyperoxia likely also carries inherent risk of harm and may not fully resolve the situation either. This chapter reviews these topics in detail and considers how investigations (e.g. arterial blood gases) can be used to target respiratory failure treatment.

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Home — Essay Samples — Nursing & Health — Respiratory System — The Respiratory System

The Purpose and Importance of Respiratory System in an Organism

Categories: Body Respiratory System

About this sample

Words: 1432 |

Published: Feb 12, 2019

Words: 1432 | Pages: 3 | 8 min read

Works Cited

Ganong, W. F. (2005). Review of medical physiology (22nd ed.). McGraw-Hill Medical.
Hall, J. E. (2015). Guyton and Hall textbook of medical physiology (13th ed.). Elsevier Saunders.
West, J. B. (2016). Respiratory physiology: The essentials (10th ed.). Wolters Kluwer.
Tortora, G. J., Derrickson, B. H. (2017). Principles of anatomy and physiology (15th ed.). Wiley.
National Heart, Lung, and Blood Institute. (n.d.). How the Lungs Work. Retrieved from https://www.nhlbi.nih.gov/health-topics/how-lungs-work
American Lung Association. (n.d.). Respiratory System. Retrieved from https://www.lung.org/lung-health-diseases/wellness/lung-health-disease
Mayo Clinic. (2022). Respiratory System. Retrieved from https://www.mayoclinic.org/diseases-conditions/respiratory-system/home/ovc-20203682
WebMD. (n.d.). The Respiratory System. Retrieved from https://www.webmd.com/lung/how-we-breathe
National Institute of Health and Care Excellence. (2019). Respiratory system and asthma. Retrieved from https://www.nice.org.uk/guidance/qs25
British Lung Foundation. (n.d.). Respiratory System. Retrieved from https://www.blf.org.uk/support-for-you/respiratory-system

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Breathing and Exchange of...
Breathing and Exchange of Gases class 11 Notes Biology

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CBSE Quick Revision Notes CBSE Class-11 Biology CHAPTER-17 Breathing and Exchange of Gases class 11 Notes Biology

The process of exchange of O 2 from the atmosphere with CO 2 produced by the cell is called breathing. It occurs in two stages of inspiration and expiration. During inspiration air enters the lungs from atmosphere and during expiration air leaves the lungs.

Respiratory Organs – Mechanism of breathing varies in different organism according to their body structure and habitat.

Human Respiratory System

Human respiratory system consists of a pair of nostrils, pharynx, larynx, bronchi and bronchioles that finally terminates into alveoli.
Nasal chamber open into pharynx that leads to larynx . Larynx contains voice box (sound box) that help in sound production.
The trachea, primary, secondary and tertiary bronchi and initial bronchioles are supported by incomplete cartilaginous rings to prevent collapsing in absence of air.
Each bronchiole terminates into an irregular walled, vascularized bag like structure called alveoli .
The branching network of bronchi, bronchioles and alveoli collectively form the lungs.
Two lungs are covered with double layered pleura having pleural fluid between them to reduce the friction on lung surface.
Conducting parts include nostrils, pharynx, larynx and trachea. Main functions include-
Transport of atmospheric air to alveoli.
Removing foreign particles from air, humidifying it and bringing it to body temperature.

Steps of Respiration

Diffusion of gases across alveolar membrane.
Transport of gases by blood.

Mechanism of Breathing

Breathing involves inspiration and expiration. During inspiration atmospheric air is drawn in and during expiration, alveolar air is released out.
Movement of air in and out takes place due to difference in pressure gradient .
Inspiration occurs when pressure inside the lung is less and expiration occurs when pressure is more in lungs than outside.
The diaphragm and external and internal intercostal muscles between the ribs help in developing pressure gradient due to change in volume.
The contraction of intercostal muscles lifts the ribs and sternum causing an increase in volume of thoracic cavity that results in decrease in pressure than the atmospheric pressure. This causes inspiration.
Relaxation of the diaphragm and intercostal muscles reduce the thoracic volume and increase the pressure causing expiration.
The volume of air involved in breathing movements is estimated by using spirometer for clinical assessment of pulmonary functions.

Respiratory Volume and Capacities

Tidal volume (TV) – volume of air inspired or expired during a normal respiration. It is about 500mL in healthy man.

Inspiratory Reserve Volume (IRV) – additional volume of air a person can inspire by forceful inspiration. It is about 2500 mL to 3000mL.

Expiatory Reserve Volume (ERV) – additional volume of air a person can expire by forceful expiration. It is about 1000 mL to 1100mL.

Residual Volume (RV) – volume of air remaining in lungs even after a forcible expiration. It is about 1100mL to 1200mL.

Inspiratory Capacity (IC) – TV + IRV

Expiratory Capacity (EC) – TV + ERV

Functional Residual Capacity (FRC) – ERV + RV

Vital Capacity (VC) – maximum volume of air a person can breathe in after a forceful expiration. ERV+ TV+ IRV

Total Lung Capacity (TLC) – total volume of air accommodated in lung at the end of forced inspiration. RV+ ERV+ TV+ IRV or Vital capacity + Residual Volume.

Exchange of Gases

Exchange of gases takes place at two sites
Alveoli to blood
Between blood and tissues.
Exchanges of gases occur by simple diffusion due to pressure/ concentration gradient, solubility of the gases and thickness of membrane.
Partial pressure of Oxygen and carbon dioxide at different part involved in diffusion varies from one part to another and moves from higher partial pressure to lower partial pressure.
Diffusion membrane is three layered thick, that is alveolar squamous epithelium, endothelium of alveolar capillaries and basement substance between them.

Transport of Gases

Transport of Oxygen

Percentage saturation of haemoglobin and partial pressure of oxygen forms sigmoid curve (oxygen dissociation curve).

Transport of Carbon dioxide

Enzyme carbonic anhydrase help in formation of carbonate ions to transport carbon dioxide.

Regulation of Respiration

Human beings have ability to maintain and moderate the rate of respiration to fulfill the demand of body tissues by neural system.
Respiratory rhythm centre is located in medulla region of hind brain. Pneumotaxic centre in pons moderate the function of respiratory rhythm centre.
Chemo-sensitive area near rhythm centre is highly sensitive to C and H+ ions that ultimately control the respiratory rate. Oxygen do not play major role in controlling rate of respiration.

Functions of Respiration –

Energy production
Maintenance of acid-base balance.
Maintenance of temperature
Return of blood and lymph.

Mountain Sickness is the condition characterised by the ill effect of hypoxia (shortage of oxygen) in the tissues at high altitude commonly to person going to high altitude for the first time.

Loss of appetite, nausea, and vomiting occurs due to expansion of gases in digestive system.
Breathlessness occurs because of pulmonary oedema.
Headache, depression, disorientation, lack of sleep, weakness and fatigue.

Disorder of Respiratory System

Asthma – it is due to allergic reaction to foreign particles that affect the respiratory tract. The symptoms include coughing, wheezing and difficulty in breathing. This is due to excess of mucus in wall of respiratory tract.
Emphysema – is the inflation or abnormal distension of the bronchioles or alveolar sacs of lungs. This occurs due to destroying of septa between alveoli because of smoking and inhalation of other smokes. The exhalation becomes difficult and lung remains inflated.
Occupational Respiratory Disorders – occurs due to occupation of individual. This is caused by inhalation of gas, fumes or dust present in surrounding of work place. This includes Silicosis, Asbestoses due to exposer of silica and asbestos. The symptom includes proliferation of fibrous connective tissue of upper part of lung causing inflammation.
Pneumonia – it is acute infection or inflammation of the alveoli of the lungs due to bacterium streptococcus pneumoniae. Alveoli become acutely inflamed and most of air space of the alveoli is filled with fluid and dead white blood corpuscles limiting gaseous exchange.

Breathing and Exchange of Gases class 11 Notes

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Question No.

1 (current)

When under certain conditions, the P 50 value of haemoglobin rises, the affinity of the pigment of combining with O 2 will

1. Remain same

4. First rise and then fall

Other Reason

In human beings, oblique fissures are associated with :

1. Right lung

2. Left lung

3. Both lungs

4. None of the above

Hemoglobin that is bonded to carbon monoxide and therefore cannot transport oxygen, is called

1. carboxyhemoglobin

2. methemoglobin

3. reduced hemoglobin

4. carbaminohemoglobin

Which of the following does not shift the oxy-haemoglobin dissociation curve to the right?

1. increased pH

2. increased carbon dioxide

3. increased temperature

4. increased 2,3 -DPG

Which of the following is entirely made of cartilage?

1. Nasal septum

Trachea divides into two right and left primary bronchi at the level of:

1. Seventh cervical vertebra

2. Third thoracic vertebra

3. Fifth thoracic vertebra

4. Seventh thoracic vertebra

Contraction of diaphragm:

Volume of air that will remain in the lungs after a normal expiration is about:

The partial pressure of oxygen is equal in

1. Atmospheric air and Alveoli

2. Alveoli and Oxygenated blood

3. Alveoli and Deoxygenated blood

4. Deoxygenated blood and Tissues

The solubility of carbon dioxide is about _____ times higher than that of oxygen across the respiratory membrane.

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Gas-Related Symptoms

Evaluation |
Treatment |
Key Points |

The gut contains < 200 mL of gas, but daily gas expulsion averages 600 to 700 mL after consumption of a standard diet plus 200 g of baked beans.

About 75% of flatus is derived from colonic bacterial fermentation of ingested nutrients and endogenous glycoproteins. Gases include hydrogen (H2), methane (CH4), and carbon dioxide (CO2). Flatus odor correlates with hydrogen sulphide concentrations. Swallowed air (aerophagia) and diffusion from the blood into the lumen also contribute to intestinal gas. Gas diffuses between the lumen and the blood in a direction that depends on the difference in partial pressures. Thus, most nitrogen (N2) in the lumen originates from the bloodstream, and most hydrogen in the bloodstream originates from the lumen.

Etiology of Gas-Related Symptoms

There are 3 main gas-related symptoms: excessive belching, distention (bloating), and excessive flatus, each with a number of causes (see table Some Causes of Gas-Related Symptoms ).

Infants 1 to 4 months of age with recurrent crying spells often appear to observers to be in pain, which in the past has been attributed to abdominal cramping or gas and termed colic . However, studies show no increase in H2 production or in mouth-to-cecum transit times in colicky infants. Hence, the cause of infantile colic remains unclear.

Excessive belching

Belching (eructation) results from swallowed air or from gas generated by carbonated beverages. Aerophagia occurs normally in small amounts during eating and drinking, but some people unconsciously swallow air repeatedly while eating or smoking and at other times, especially when anxious or in an attempt to induce belching. Excessive salivation increases aerophagia and may be associated with various gastroesophageal (GI) disorders (eg, gastroesophageal reflux disease ), ill-fitting dentures, certain medications, gum chewing, or nausea of any cause.

Most swallowed air is eructated. Only a small amount of swallowed air passes into the small bowel; the amount is apparently influenced by position. In an upright person, air is readily belched; in a supine person, air trapped above the stomach fluid tends to be propelled into the duodenum. Excessive eructation may also be voluntary; patients who belch after taking antacids may attribute the relief of symptoms to belching rather than to antacids and may intentionally belch to relieve distress.

A rare cause of excessive belching is supragastric belching. In supragastric belching, a rapid entry of air into the esophagus is expelled after tensing the abdomen. It may occur under volition or unconsciously and can severely affect quality of life ( 1 ).

Distention (bloating)

Abdominal bloating may occur in isolation or along with other GI symptoms in patients with functional disorders (eg, aerophagia, nonulcer dyspepsia , gastroparesis, irritable bowel syndrome ) or organic disorders (eg, ovarian cancer , colon cancer ). Gastroparesis (and consequent bloating) also has many nonfunctional causes, the most important of which is autonomic visceral neuropathy due to diabetes; other causes include postviral infection, medications with anticholinergic properties, and long-term opioid use. However, excessive intestinal gas is not clearly linked to complaints of distention and bloating. In most healthy people, 1 L/hour of gas can be infused into the gut with minimal symptoms. It is likely that many symptoms are incorrectly attributed to “too much gas.”

On the other hand, some patients with recurrent GI symptoms often cannot tolerate small quantities of gas: Retrograde colonic distention by balloon inflation or air instillation during colonoscopy often elicits severe discomfort in some patients (eg, those with irritable bowel syndrome) but minimal symptoms in others. Similarly, patients with eating disorders (eg, anorexia nervosa , bulimia nervosa ) often misperceive and are particularly stressed by symptoms such as bloating. Thus, the basic abnormality in patients with gas-related symptoms may be a hypersensitive intestine. Altered motility may contribute further to symptoms.

Excessive flatus

There is great variability in the quantity and frequency of rectal gas passage. As with stool frequency, people who complain of flatulence often have a misconception of what is normal. The average number of gas passages is about 13 to 21/day. Objectively recording flatus frequency (using a diary kept by the patient) is a first step in evaluation.

Flatus is a metabolic byproduct of intestinal bacteria; almost none originates from swallowed air or back-diffusion of gases (primarily nitrogen) from the bloodstream. Bacterial metabolism yields significant volumes of hydrogen, methane, and carbon dioxide.

Hydrogen is produced in large quantities in patients with malabsorption syndromes and after ingestion of certain fruits and vegetables containing indigestible carbohydrates (eg, baked beans), sugars (eg, fructose), or sugar alcohols (eg, sorbitol ). In patients with disaccharidase deficiencies (most commonly lactase deficiency), large amounts of disaccharides pass into the colon and are fermented to hydrogen. Celiac disease , tropical sprue , pancreatic insufficiency, and other causes of carbohydrate malabsorption should also be considered in cases of excess colonic gas.

Methane is also produced by colonic bacterial metabolism of the same foods (eg, dietary fiber). However, about 10% of people have bacteria that produce methane but not hydrogen.

Carbon dioxide is also produced by bacterial metabolism and is generated in the reaction of bicarbonate and hydrogen ions. Hydrogen ions may come from gastric hydrochloric acid or from fatty acids released during digestion of fats—the latter sometimes produces several hundred milliequivalents of hydrogen ions. The acid products released by bacterial fermentation of unabsorbed carbohydrates in the colon may also react with bicarbonate to produce carbon dioxide. Although bloating may occasionally occur, the rapid diffusion of carbon dioxide into the blood generally prevents distention.

Diet accounts for much of the variation in flatus production among individuals, but poorly understood factors (eg, differences in colonic flora and motility) may also play a role.

Despite the flammable nature of the hydrogen and methane in flatulence, working near open flames is not hazardous. However, gas explosion, even with fatal outcome, has been reported during jejunal and colonic surgery and colonoscopy, when diathermy was used during procedures in patients with incomplete bowel cleaning.

Etiology reference

1. Koukias N, Woodland P, Yazaki E, Sifrim D : Supragastric belching: Prevalence and association with gastroesophageal reflux disease and esophageal hypomotility. J Neurogastroenterol Motil 21(3):398–403, 2015. doi: 10.5056/jnm15002

Evaluation of Gas-Related Symptoms

History of present illness in patients with belching should be directed at finding the cause of aerophagia, especially dietary causes.

In patients complaining of gas, bloating, or flatus, the relationship between symptoms and meals (both timing and type and amount of food), bowel movements, and exertion should be explored. Certain patients, particularly in the acute setting, may use the term "gas" to describe their symptoms of coronary ischemia. Changes in frequency and color and consistency of stool are sought. History of weight loss is noted.

Review of systems should seek symptoms of possible causes, including diarrhea and steatorrhea (malabsorption syndromes such as celiac sprue, tropical sprue, disaccharidase deficiency, and pancreatic insufficiency) and weight loss (cancer, chronic malabsorption).

Past medical history should review all components of the diet for possible causes (see table Some Causes of Gas-Related Symptoms ).

Physical examination

The examination is generally normal, but in patients with bloating or flatus, signs of an underlying organic disorder should be sought on abdominal, rectal, and (for women) pelvic examination.

The following findings are of concern:

Weight loss

Blood in stool (occult or gross)

"Gas" sensation in chest

Interpretation of findings

Chronic, recurrent bloating or distention in a patient with abdominal pain that is related to defecation and associated with change in frequency or consistency of stool but without red flag findings suggests irritable bowel syndrome .

Long-standing symptoms in an otherwise well young person who has not lost weight are unlikely to be caused by serious physiologic disease, although an eating disorder should be considered, particularly in young women. Bloating accompanied by diarrhea, weight loss, or both (or only after ingestion of certain foods) suggests a malabsorption syndrome .

Testing is not indicated for belching unless other symptoms suggest a particular disorder.

Testing for carbohydrate intolerance (eg, lactose, fructose) with breath tests should be considered particularly when the history suggests significant consumption of these sugars. Testing for small intestinal bacterial overgrowth should also be considered, particularly in patients who also have diarrhea, weight loss, or both, preferably by aerobic and anaerobic culture of small-bowel aspirates obtained during upper GI endoscopy. Testing for bacterial overgrowth with hydrogen breath tests, generally glucose-hydrogen breath tests, is prone to false-positive (ie, with rapid transit) and false-negative (ie, when there are no hydrogen-producing bacteria) results. Testing for rare conditions such as sucrase-isomaltase deficiency can be considered in patients with refractory or severe symptoms ( 1 ).

New, persistent bloating in middle-aged or older women (or those with an abnormal pelvic examination) should prompt pelvic ultrasonography to rule out ovarian cancer.

Evaluation reference

1. Husein DM, Rizk S, Naim HY : Differential effects of sucrase-isomaltase mutants on its trafficking and function in irritable bowel syndrome: Similarities to congenital sucrase-isomaltase deficiency. Nutrients 13(1):9, 2021. doi: 10.3390/nu13010009

Treatment of Gas-Related Symptoms

Belching and bloating are difficult to relieve because they are usually caused by unconscious aerophagia or increased sensitivity to normal amounts of gas ( 1 ). Aerophagia may be reduced by eliminating gum and carbonated beverages, cognitive-behavioral techniques to prevent air swallowing, and management of associated upper GI diseases (eg, peptic ulcer). Foods containing unabsorbable carbohydrates should be avoided. Even lactose-intolerant patients generally tolerate up to 1 glass of milk drunk in small amounts throughout the day. The mechanism of repeated belching should be explained and demonstrated. When aerophagia is troublesome, behavioral therapy to encourage open-mouth, diaphragmatic breathing and minimize swallowing may be effective.

Symptoms of excess flatus are treated with avoidance of triggering substances (see table Some Causes of Gas-Related Symptoms

Charcoal -lined undergarments are available.

Probiotics may also reduce bloating and flatulence by modulating intestinal bacterial flora, but data in this area are limited.

Antibiotics are useful in patients with documented small intestinal bacterial overgrowth .

Certain aromatic oils (carminatives) can relax smooth muscle and relieve pain caused by cramps in some patients. Slow-release peppermint oil is the most commonly used agent in this class.

Functional bloating, distention, and flatus may run an intermittent, chronic course that is only partially relieved by therapy. When appropriate, reassurance that these problems are not detrimental to health is important.

Treatment reference

1. Moshiree B, Drossman D, Shaukat A . AGA Clinical Practice Update on Evaluation and Management of Belching, Abdominal Bloating, and Distention: Expert Review. Gastroenterology . 2023;165(3):791-800.e3. doi:10.1053/j.gastro.2023.04.039

Testing should be guided by the clinical features.

Be wary of new-onset, persistent symptoms in older adults.

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Guest Essay

Oil and Gas Companies Are Trying to Rig the Marketplace

A hazy image of wind turbines and electrical wires.

By Andrew Dessler

Dr. Dessler is a professor of atmospheric sciences and the director of the Texas Center for Climate Studies at Texas A&M University.

Many of us focused on the problem of climate change have been waiting for the day when renewable energy would become cheaper than fossil fuels.

Well, we’re there: Solar and wind power are less expensive than oil, gas and coal in many places and are saving our economy billions of dollars . These and other renewable energy sources produced 30 percent of the world’s electricity in 2023, which may also have been the year that greenhouse gas emissions in the power sector peaked. In the United States alone, the amount of solar and wind energy capacity waiting to be built and connected to the grid is 18 times the amount of natural gas power capacity in the queue.

So you might reasonably conclude that the market is pivoting, and the end for fossil fuels is near.

But it’s not. Instead, fossil fuel interests — including think tanks, trade associations and dark money groups — are often preventing the market from shifting to the lowest cost energy.

Similar to other industries from tobacco to banking to pharmaceuticals, oil and gas interests use tactics like lobbying and manufacturing “grass-roots” support to maximize profits. They also spread misinformation: It’s well documented that fossil fuel interests tried to convince the public that their products didn’t cause climate change, in the same way that Big Tobacco tried to convince the public that its products didn’t harm people’s health.

But as renewables have become a more formidable competitor, we are now seeing something different: a large-scale effort to deceive the public into thinking that the alternative products are harmful, unreliable and worse for consumers. And as renewables continue to drop in cost, it will become even more critical for policymakers and others to challenge these attempts to slow the adoption of cheaper and healthier forms of energy.

One technique the industry and its allies have used is to spread falsehoods — for example, that offshore wind turbines kill whales or that renewable energy is prohibitively expensive — to stop projects from getting built. What appear to be ordinary concerned citizens or groups making good-faith arguments about renewable energy are actually a well-funded effort to disseminate a lie. Researchers at Brown University have revealed a complex web of fossil fuel interests, climate-denial think tanks and community groups that are behind opposition to wind farms off New Jersey, Massachusetts and Rhode Island.

Fossil fuel interests also donate piles of money to sympathetic politicians who then make false claims about renewable energy and push oil and gas on their constituents even when renewable energy is cheaper. After the Texas blackout in 2021, which was caused in part by the failure of the natural gas system , politicians blamed renewable energy, and have since argued that more natural gas is needed to strengthen the state electrical grid .

The Texas grid could certainly be made more robust. But building backup natural gas plants that should ultimately sit idle 90 percent of the time is probably the most expensive way to address the problem, compared with approaches like paying consumers to cut their energy use when the electrical grid nears its limits.

One of the most pervasive pieces of misinformation being spread by fossil fuel interests is that we cannot run our society on renewable energy . It is true that the sun doesn’t always shine and the wind doesn’t always blow. However, we could deal with this by expanding our existing electrical grid to allow us to move clean energy from regions with excess to those with shortfalls. When that’s not sufficient, power sources that can be quickly turned on and off, like batteries or hydroelectricity, can match supply and demand. In the current U.S. grid, natural gas provides the primary balance for intermittent wind and solar, and we can keep using it that way — in very limited quantities — when we need it. One study published in 2020 showed that we could operate a grid that is 90 percent clean energy and 10 percent natural gas by 2035, which would produce energy for a cost similar to that of a grid with a continuation of current policies.

Alarmingly, fossil fuel interests are also looking to dictate how schoolchildren learn about the environment. Children are some of the most powerful messengers when it comes to climate awareness, so fossil fuel promoters are keen to shape their understanding from the start. They have succeeded in getting the Texas State Board of Education to reject textbooks that accurately depict the effects of climate change and extreme weather.

Fossil fuels do deserve credit for getting us to where America is today — rich beyond the dreams of anyone living before the Industrial Revolution. But oil and gas are not the fuels of the future; they are changing the climate and generating air pollution that kills millions of people each year . They also bolster autocratic petrostates, fuel conflicts over energy resources and contribute to geopolitical instability . Simply put, the industry’s lies can cost consumers their health, their money and their security.

With existing technologies, the United States can largely phase out oil, gas and coal. The last 5 percent to 10 percent of that process may be expensive, but credible estimates place the cost of getting to net-zero emissions within the historical range of energy costs. This means that a sustainable future hinges on politics, not technology or science.

Policymakers must now call out the fact that an industry facing obsolescence is distorting the market to try to shut out a superior competitor, clean energy. Make no mistake: Failure to do so may mean a planet no longer able to sustain human life in the style to which we have become accustomed.

Andrew Dessler is a professor of atmospheric sciences and the director of the Texas Center for Climate Studies at Texas A&M University. He is a writer of the newsletter The Climate Brink .

The Times is committed to publishing a diversity of letters to the editor. We’d like to hear what you think about this or any of our articles. Here are some tips . And here’s our email: [email protected] .

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Markets News

What You Need To Know About the Blackrock-Backed Texas Stock Exchange

TXSE Plans to Start Trading Next Year, Have Own Listings by 2026

Aaron M. Sprecher / Getty Images

Key Takeaways

The TXSE Group announced plans Wednesday to officially file registration papers with the Securities and Exchange Commission (SEC) to create the Texas Stock Exchange.
The project has received $120 million in funding, with investors including BlackRock and Citadel Securities.
The Wall Street Journal reported backers of the effort "pledge it will be more CEO-friendly" than the New York Stock Exchange and Nasdaq.

Texas may soon be the home of a new national stock exchange, as the TXSE Group announced plans Wednesday to officially file registration papers with the Securities and Exchange Commission (SEC ) to create the Texas Stock Exchange.

The new exchange has raised around $120 million so far from a group of over two dozen investors including Wall Street giants BlackRock ( BLK ) and Citadel Securities. The exchange would be fully electronic but be headquartered in Dallas, the company said.

TXSE Group Chief Executive Officer (CEO ) James Lee told The Wall Street Journal that the group aims to file with the SEC this year, start facilitating trades next year, and begin hosting its own listings by 2026.

TXSE Aims To 'Be More CEO-Friendly' Than NYSE, Nasdaq

Those supporting the planned Texas exchange "pledge it will be more CEO-friendly" than the dominant exchanges in New York, the New York Stock Exchange (NYSE) and Nasdaq , the Journal said.

The Texas exchange hopes to benefit from companies that are frustrated with regulations like Nasdaq's Board Diversity Rule, and increasing compliance costs that come with listing on the exchanges, the Journal reported. Lee told the newspaper that the TXSE is apolitical.

Exchanges based in locations other than New York City used to be more common, but regional exchanges like those based in Boston, Chicago, and Philadelphia were acquired and folded into the NYSE and Nasdaq over time. Several smaller exchanges still exist across the U.S., but handle much less trading activity than the NYSE and Nasdaq .

Texas Has Become Growing Business Hub

The TXSE Group said that Texas is "home to more Fortune 500 companies than any other state," making now an "opportune time" to establish the exchange, Lee said.

"Texas and the other states in the southeast quadrant have become economic powerhouses," Lee said. "Combined with the demand we are seeing from investors and corporations for expanded alternatives to trade and list equities, this is an opportune time to build a major, national stock exchange in Texas."

Texas' role in the business community has been in the spotlight in recent years as a number of high-profile tech companies like Tesla ( TSLA ) and Oracle ( ORCL ) have shifted their headquarters from California to the state.

Tesla shareholders are set to vote at next week's annual shareholder meeting on a number of issues, including whether the company should leave Delaware to re-incorporate in Texas after a Delaware court ruled against the company and its multibillion-dollar pay package for CEO Elon Musk.

PRNewswire. " TXSE Group Inc. Announces Plans to Create the Texas Stock Exchange ."

The Wall Street Journal. " New Texas Stock Exchange Takes Aim at New York’s Dominance ."

Nasdaq. " NASDAQ’S BOARD DIVERSITY RULE: WHAT COMPANIES SHOULD KNOW ."

Nasdaq. " 5900. COMPANY LISTING FEES ."

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CATL still dominates the EV battery market share in 2024, but BYD is gaining ground

As global EV battery consumption continues rising, the most prominent players, including CATL and BYD, continue dominating the market in 2024. CATL still owns over a third of the market, but BYD looks to close the gap with new lower-priced EVs.

CATL and BYD are still the EV battery market leaders

Through the first four months of 2024, global EV battery consumption reached 216.2 GWh. That’s up 21.8% from the 177.6 GWh last year.

CATL had the largest share by far, with 81.1 GWh installed, up 30% YOY (62.6 GWh). According to new data from South Korean research firm SNE Research, CATL accounted for 37.7% of the market through April 2024.

The EV battery giant supplies top-selling models, including the Tesla Model 3, Model Y , BMW iX, Mercedes EQ series, and Volkswagen ID series, in China.

With two new planned overseas plants , CATL looks to expand outside of China. The new factories come in addition to the six already planned in Germany, Thailand, Hungary, Indonesia, and two in the US.

Despite a slow start to 2024 due to the Chinese New Year, BYD saw solid sales growth. BYD ranked second with a 15.4% share.

BYD’s battery installations hit 33.2 GWh through April, up 18.3% from last year. The company’s market share was up from 14.3% through March.

With a series of new, low-priced vehicles hitting the market, BYD looks to close the gap throughout the year. BYD’s cheapest EV, the Seagull Honor Edition , starts at just $9,700 (69,800 yuan) in China.

Most recently, BYD launched its fifth-gen Dual Motor (DM) hybrid tech. BYD’s DM 5.0 has fuel consumption as low as 2.9 liters per 100 km with over 1,300 miles (2,100 km) CLTC range.

According to BYD chairman and president Wang Chuanfu, that’s three times more than traditional gas-powered vehicles.

Are South Korean battery makers falling behind?

According to the report, the top three South Korean EV battery makers represented 22.8% of the market, down 2.4% YOY.

LG Energy Solution was the largest among the three, accounting for 13% of the market. LG’s consumption was up 7.8% from last year at 28 GWh.

The growth was fueled by higher Tesla Model 3, Model Y, Ford Mustang Mach-E, and Hyundai IONIQ 6 sales in Europe and North America. The report notes that GM’s Ultium Cells is expected to lead the North American market with batteries that meet the IRA, which could help boost LG’s market share.

GM’s new electric vehicles, including the Chevy Equinox EV, Blazer EV, and Silverado EV, are hitting the North American market.

Ford also kicked off production of the electric Explorer this week in Europe based on Volkswagen’s MEB platform.

Meanwhile, Samsung SDI saw the highest growth rate at 32.9%, installing 10.9 GWh through April. Samsung placed fourth with a 5.1% share.

Samsung’s growth was boosted by higher BMW i4, i5, iX, and Rivian R1T and R1S sales.

Korea’s SK On was fifth with 4.8% of the market, with 10.3 GWh installed, down 2% from last year.

With the refreshed Hyundai IONIQ 5 and Kia EV6, equipped with SK’s fourth-gen batteries rolling out, sales are expected to recover.

The only Japanese automaker to make the top ten, Panasonic placed sixth with 10.2 GWh, down 29.5% YOY. Panasonic held 4.7% market share.

CALB (4.3%), Eve Energy (2.3%), Gotion (2.2%), and Sunwoda (2.0%) rounded out the top ten EV battery makers through April 2024.

Source: CnEVPost , SNE Research

FTC: We use income earning auto affiliate links. More.

Peter Johnson is covering the auto industry’s step-by-step transformation to electric vehicles. He is an experienced investor, financial writer, and EV enthusiast. His enthusiasm for electric vehicles, primarily Tesla, is a significant reason he pursued a career in investments. If he isn’t telling you about his latest 10K findings, you can find him enjoying the outdoors or exercising

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Biology Important Questions
Class 11 - Biology
Chapter 17: Breathing Exchange Gases

Important Questions for Class 11 Biology Chapter 17 Breathing and Exchange of Gases

Important Questions for Class 11 Biology Chapter 17 Breathing and Exchange of Gases are compiled here for students to boost their preparation. These questions are created by subject experts after thorough research on previous years papers, exam pattern and difficulty level of exam. So, students are advised to solve these questions before their exam. It will make them feel confident, so they will be able to solve any type of question asked from this chapter during the Biology paper.

Breathing is a fundamental characteristic that is exhibited by all living entities. Our cells need to be continuously administered with oxygen to carry out their functionality. The cells in return release carbon dioxide. This exchange of oxygen from the atmosphere with carbon dioxide generated by the cells is called breathing. It is also referred to as respiration. The two main processes occurring in respiration are inspiration and expiration that are carried out by creating pressure gradients between the alveoli and atmosphere through specialized muscles. Through this chapter, we understand the various respiratory organs and the different mechanisms that we go through in order to breathe.

Very Short Answer Type Questions

Q.1. Define: a) Tidal volume b) Residual volume c) Asthma A.1. a) Tidal volume (TV) is the air volume expired or inspired during respiration. In a healthy individual, it is about 500ml. Hence per minute, it is about 6000-8000ml of air.

b) Residual volume (RV) is the air volume left in the lungs following a forcible expiration which is about 1100-1200ml.

c ) It is a disease that is caused because of an allergic reaction to foreign particles. Inflammation of the bronchi causes breathing difficulty and hence coughing and wheezing.

Q.2. Write the name and important function of the fluid-filled double membranous layer surrounding the lungs. A.2. It is pleura and the fluid is pleural fluid. The outer and inner pleural membrane collectively reduce friction or resistance on the lungs.

Q.3. Which is the prime site for the exchange of gases in our body? A.3. Alveoli.

Q.4. Why does smoking cigarette cause emphysema? A.4. It is a chronic disease of the respiratory system where inflation of the alveolar occurs. Over a period of time, cigarette smoking or even inhalation of smoke causes the damage of septa between the alveoli and of its elastic tissue is substituted by the connective tissue in the lungs. The respiratory surface decreases which cause emphysema.

Q.5. Organize the following in ascending order a) Tidal volume b) Residual volume c) Inspiratory reserve volume d) Expiratory capacity

a) Tidal Volume – 500ml.

b) Residual Volume – 1100-1200 ml.

c) Inspiratory reserve volume – 2500-3000ml.

d) Expiratory capacity – 1500-1600ml Tidal Volume, Residual Volume, Expiratory Capacity, Inspiratory Reserve Volume.

Q.6. Write the organs of respiration in the entities given below: a) Flatworm b) Frog c) Birds d) Cockroach

a) Flatworm – Body surface.

b) Frog – Moist skin and lungs.

c) Birds – Lungs.

d) Cockroach – Tracheal tubes.

Q.7. Mention the main parts involved in the initiating a pressure gradient between the lungs and the atmosphere during normal respiration.

A.7. The diaphragm and a specialized set of external and intercostal muscles between the ribs aid in the generation of pressure gradient during respiration.

Q.8. What Is Breathing?

A.8. Breathing is defined as the biological process in which air moves in and out of the lungs. This process is carried out by the various organs of the human respiratory system.

Q.9.What are the formulae of Respiratory Quotient (RQ)?

A.9. The formulae of Respiratory Quotient-

RQ = Volume of Carbon dioxide eliminated / volume of Oxygen consumed(RQ)

Q.10. What is the exchange of gases?

A.10. The exchange of gases is defined as the physical process, through which gases move passively by diffusion across a surface.

Short Answer Type Questions

Q.1. Write the various modes of transportation of carbon dioxide in the blood. A.1. It is carried in the blood in three forms:

Dissolved state under normal pressure and temperature, 7% of CO 2 is transported by physical solution
As carbamino compounds, carbon dioxide directly combines with Hb to form an unstable compound, the carbamino compounds
As bicarbonate ions

Q.2. Explain why the diffusion of carbon dioxide by the diffusion membrane per unit difference in partial pressure is much greater compared to oxygen.

A.2. The solubility rate of CO 2 is 22-25 times more than oxygen.

Q.3. List the following steps in a sequential manner for the completion of the respiration process. a) Diffusion of oxygen and CO 2 across the alveolar membrane b) Transportation of gases by blood c) Utilization of oxygen for catabolic reactions by the cells and hence the resultant release of CO 2 d) Pulmonary ventilation through which atmospheric air is drawn in and carbon dioxide-rich alveolar air is given out e) Diffusion of oxygen and carbon dioxide between tissues and blood A.3.

d) Pulmonary ventilation through which atmospheric air is drawn in and carbon dioxide-rich alveolar air is given out

a) Diffusion of oxygen and CO 2 across the alveolar membrane

b) Transportation of gases by blood

e) Diffusion of oxygen and CO 2 between tissues and blood

c) Utilization of oxygen for catabolic reactions by the cells and hence the resultant release of CO 2

Q.4. State the differences between the following: a) Expiratory and inspiratory reserve volume b) Total lung capacity and vital capacity c) Occupational respiratory disorder and Emphysema A.4. The differences are as follows:

Q.5. Name the organs of respiration in cockroach, earthworm and birds?

Cockroaches respire through small openings on the sides of its body called spiracles.
Earthworm respire through the skin.
Birds respire through the lungs.

Q.6. What is Respiratory Quotient?

A.6. The actual ratio of the volume of carbon dioxide eliminated to the volume of oxygen consumed during the act of cellular respiration is called the respiratory quotient.it is also referred as the respiratory ratio and is denoted by RQ.

The formulae of Respiratory Quotient is given by:

RQ = volume of Carbon dioxide eliminated / volume of Oxygen consumed

Long Answer Type Questions

Q.1. Write a note on the mechanism of breathing A.1. a) Inspiration – It is inducted by the diaphragm contraction that raises the volume of the thoracic chamber in the anteroposterior axis. The inter-costal muscles contracts causing external protrusion of the sternum and ribs resulting in an increment in the volume of the thoracic chamber in the dorsoventral axis. This increase in the thoracic volume results in a similar increase in pulmonary volume causing reduced intrapulmonary pressure to lesser than the atmospheric pressure which results in inspiration. b) Expiration – The inter-costal muscles reverse the sternum and diaphragm to their original positions with the diaphragm relaxing, which decreases the thoracic volume and hence the pulmonary volume. Expulsion of air occurs as the intra-pulmonary pressure increases to a level somewhat above the atmospheric pressure causing expiration.

Q.2. Describe the role of the neural system in controlling respiration. A.2. The neural system maintains and moderates the respiratory rhythm as per the demands of the body tissues. The respiratory rhythm centre present in the brain is responsible for regulation. The pneumotaxic centre, another region in the pons of the brain, moderates the functions of the respiratory rhythm centre. The neural signals from this centre have the ability to reduce the duration of inspiration hence altering the rate of respiration. A chemosensitive area present adjacent to the rhythm centre is very sensitive to hydrogen ions and CO 2 which activate this centre by an increase of these substances. These send down a signal to the rhythm centre to cause essential adjustments in the process which can cause the elimination of these substances. Changes in CO 2 and hydrogen ions are recognized by receptors linked with aortic arch and carotid artery, thereby sending signals for corrective actions to the rhythm centre. Know more about the exchange of gases and other related biological concepts by registering at BYJU’S.

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COMMENTS

13.4 Gas Exchange
13.4 Summary. Gas exchange. is the biological process through which gases are transferred across cell membranes to either enter or leave the blood. Gas exchange takes place continuously between the blood and cells throughout the body, and also between the blood and the air inside the lungs. Gas exchange in the lungs takes place in.
The Respiratory System: An Essential Component of Human ...
This exchange is facilitated by the partial pressure gradients of the gases and the large surface area of the alveoli. Additionally, the respiratory system plays a role in regulating blood pH by controlling the levels of carbon dioxide, a component of the body's acid-base balance. Pathologies and Advances in Respiratory Medicine
The respiratory system review (article)
Respiratory system. The body system responsible for gas exchange between the body and the external environment. Pharynx (throat) Tube connected the nose/mouth to the esophagus. Larynx (voice box) Tube forming a passage between the pharynx and trachea. Trachea. Tube connecting the larynx to the bronchi of the lungs. Bronchi.
Explore How Gas Exchange In The Lungs Takes Place In Vivid Detail
The transportation of gases is a very efficient process. Oxygen molecules get carried by the haemoglobin molecules of the red blood cells since it has a great affinity for oxygen. Each haemoglobin molecule binds to four molecules of oxygen. These oxygen molecules are picked up by haemoglobin and get transported by the blood to various tissues.
22.4 Gas Exchange
Internal respiration is gas exchange that occurs at the level of body tissues ( Figure 22.4.3 ). Similar to external respiration, internal respiration also occurs as simple diffusion due to a partial pressure gradient. However, the partial pressure gradients are opposite of those present at the respiratory membrane.
116 13.1 Case Study: Respiratory System and Gas Exchange
The process of respiration, in which oxygen moves from the outside air into the body and carbon dioxide and other waste gases move from inside the body into the outside air. The organs of the respiratory system, including the lungs, bronchial tubes, and the rest of the respiratory tract. How the respiratory tract protects itself from pathogens ...
8.5: Gas Exchange
Internal respiration is the exchange of gases with the internal environment, and occurs in the tissues. The actual exchange of gases occurs due to simple diffusion. Energy is not required to move oxygen or carbon dioxide across membranes. Instead, these gases follow pressure gradients that allow them to diffuse.
Breathing and exchange of gases
Learn. Partial pressure and exchange of gases. Alveoli - site of gaseous exchange. Hemoglobin. Hemoglobin moves O2 and CO2.
13.1 Case Study: Respiratory System and Gas Exchange
respiratory system. — the system that exchanges gases (such as oxygen and carbon dioxide) between the body and the outside air. Specifically, you will learn about: The process of respiration, in which oxygen moves from the outside air into the body and carbon dioxide and other waste gases move from inside the body into the outside air.
Gas Exchange
In health, the respiratory system is exceptionally well adapted to performing efficient gas exchange and able to closely match O 2 uptake and CO 2 elimination to the body's constantly changing metabolic demands. However, disease can quickly impair these processes and result in harmfully low levels of O 2, high levels of CO 2, or both.Inadequate gas exchange (respiratory failure) is the most ...
The Gas Exchange And Transport
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Structure and function of the gas exchange system
The gas exchange system affects oxygen, nitrogen and carbon dioxide from the air. Find out more with BBC Bitesize in this article for 11-14 year old students.
Breathing and Exchange of Gases: Important Questions
State how it helps in gaseous exchange during respiration. Ans. When we are performing inspiration and expiration, gasses move freely by the process of diffusion. And the diffusion of any molecule takes place from high to low concentration. There is a direct relation between the process of diffusion and the pressure caused by the gas alone.
Breathing and Exchange of Gases Class 11 Notes Biology Chapter 17
Topic 2 Respiration Processes : Breathing and Gaseous Exchange. (i) Breathing (pulmonary ventilation) is the inflow of atmospheric air and release (outflow) of CO 2 rich alveolar air. (ii) Exchange of gases (O 2 and CO 2) across alveolar membrane as well as in tissues. (iii) Transport of gases by the blood.
The Respiratory System: [Essay Example], 1432 words
Get original essay. The major organs that make up the respiratory system consist of the three major parts: the airway, the lungs, and the muscles of respiration. Within those three major parts, there are organs that aid and pave the way for a healthy respiratory system. The airway, which includes the nose (Nasal cavity), mouth (Oral cavity ...
Features of Gas Exchange Surfaces
All gas exchange surfaces have features in common. These features allow the maximum amount of gases to be exchanged across the surface in the smallest amount of time. They include: Large surface area to allow faster diffusion of gases across the surface. Thin walls to ensure diffusion distances remain short.
Breathing And Exchange of Gases
According to the chapter Breathing and Exchange of Gases, the respiration process includes the following terms: Tidal Volume (TV): It is the volume of the air inspired and expired in one breath. 500mL is considered a healthy TV in human adults. Inspiratory Reserve Volume (IRV): It is the forcible inspiration or the additional air volume of air.
Breathing and Exchange of Gases class 11 Notes Biology
CHAPTER-17. Breathing and Exchange of Gases class 11 Notes Biology. The process of exchange of O 2 from the atmosphere with CO 2 produced by the cell is called breathing. It occurs in two stages of inspiration and expiration. During inspiration air enters the lungs from atmosphere and during expiration air leaves the lungs.
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Lungs. The actual exchange of gases takes place in tiny, innumerable structures called the alveoli and the capillaries in the lungs. Here, deoxygenated blood gets re-oxygenated and sent to the heart, where it is pumped to all the other parts of the body. Typically, most illnesses and diseases of the respiratory system occur when the alveoli or ...
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This work is devoted to the study of gas-dynamic processes in the operation of climate control systems in the cabins of vehicles (HVAC), focusing on pressure values. This research examines the issue of assessing the required values of air overpressure inside the locomotive cabin, which is necessary to prevent gas exchange between the interior of the cabin and the outside air through leaks in ...
Respiration- An overview of Respiration and Transportation of Gases
What is Respiration? Respiration is the process through which living organisms take in oxygen and give out carbon dioxide to release energy. So, naturally, respiration is a major and vital process of gas exchange. The transport of gases during respiration, both oxygen and carbon dioxide are carried out by the blood cells.
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CATL still dominates the EV battery market, but BYD gains ground
CATL and BYD are still the EV battery market leaders. Through the first four months of 2024, global EV battery consumption reached 216.2 GWh. That's up 21.8% from the 177.6 GWh last year. CATL ...
Important Questions for Class 11 Biology Chapter 17 Breathing and
Q.10. What is the exchange of gases? A.10. The exchange of gases is defined as the physical process, through which gases move passively by diffusion across a surface. Short Answer Type Questions. Q.1. Write the various modes of transportation of carbon dioxide in the blood. A.1. It is carried in the blood in three forms:

22.4 Gas Exchange

Gas Exchange

Gas Laws and Air Composition

Solubility of Gases in Liquids

Ventilation and Perfusion

External Respiration

Internal Respiration

Everyday Connection – Hyperbaric Chamber Treatment

Chapter Review

Review Questions

116 13.1 Case Study: Respiratory System and Gas Exchange

Case Study: Cough That Won’t Quit

Chapter Overview: Respiratory System

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8.5: Gas Exchange

Learning Objectives

Gas Exchange

Gas Laws and Air Composition

Solubility of Gases in Liquids

Ventilation and Perfusion

External Respiration

Internal Respiration

Everyday Connections: Hyperbaric Chamber Treatment

Chapter Review

Critical Thinking Questions

Contributors and Attributions

Unit 2: Breathing and exchange of gases

Mechanism of breathing

Exchange and transport of gases

Regulation and disorders of respiration

13.1 Case Study: Respiratory System and Gas Exchange

Case Study: Cough That Won’t Quit

Chapter Overview: Respiratory System

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