critical thinking questions about the nervous system

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Chapter 12| The Nervous System

• How are neurons similar to other cells? How are they unique?
• Multiple sclerosis causes demyelination of axons in the brain and spinal cord. Why is this problematic?
• How does myelin aid propagation of an action potential along an axon? How do the nodes of Ranvier help this process?
• What are the main steps in chemical neurotransmission?
• What methods can be used to determine the function of a particular brain region?
• What are the main functions of the spinal cord?
• What are the main differences between the sympathetic and parasympathetic branches of the autonomic nervous system?
• What are the main functions of the sensory-somatic nervous system?
• What are the main symptoms of Alzheimer’s disease?
• What are possible treatments for patients with major depression?

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Critical Thinking Questions

When you stick your hand in a bucket of ice, it grows numb after a while. Based on what you know regarding neuronal signaling, explain how the sensation of touch is blocked from signaling to the brain.

Lidocaine is a local anesthetic that works by blocking voltage-gated sodium channels. Explain how blocking voltage-gated sodium channels would cause numbness and pain.

• The sympathetic nervous system is activated by stressful situations, whereas the parasympathetic nervous system resets organ function of sympathetic reactions and allows animals to “rest and digest.”
• The parasympathetic nervous system is activated by stressful situations, whereas the sympathetic nervous system resets organ function of sympathetic reactions and allows animals to “rest and digest.”
• The sympathetic nervous system is involved in unconscious body function control, whereas the parasympathetic nervous system is involved in conscious body function control.
• The parasympathetic nervous system is involved in unconscious body function control, whereas the sympathetic nervous system is involved in conscious body function control.
• The sensory-somatic nervous system transmits information from the skin, muscles, and sensory organs to the peripheral nervous system. Motor information is sent to and from the central nervous system and the muscles.
• The sensory-somatic nervous system transmits information from the skin, muscles, and sensory organs to the central nervous system. Motor information is sent to and from the central nervous system and the muscles.
• The sensory-somatic nervous system transmits information from the skin, muscles, and sensory organs to the central nervous system. Motor information is sent to and from the peripheral nervous system and the muscles.
• The sensory-somatic nervous system transmits information from the skin, muscles, and sensory organs to the peripheral nervous system. Motor information is sent to and from the peripheral nervous system and the muscles.
• During stress, multiple preganglionic neurons can synapse on one postganglionic neuron, and the adrenal gland releases adrenaline.
• During stress, one preganglionic neuron can synapse on multiple postganglionic neurons, and the thymus gland releases norepinephrine.
• During stress, one postganglionic neuron can synapse on multiple preganglionic neurons, and the adrenal gland releases norepinephrine.
• During stress, one preganglionic neuron can synapse on multiple postganglionic neurons, and the adrenal gland releases norepinephrine.

The apolipoprotein E (APOE) gene is associated with Alzheimer's disease. This gene has three possible alleles, E2, E3 and E4. Recall that each person has two alleles for a gene. The graph shows Alzheimer risk of a person and the APOE allele combination they have.

What can we conclude from this graph?

• E4 allele increases likelihood of having Alzheimer's. E4/E4 combination has the most risk.
• E3 allele increases likelihood of having Alzheimer's. E3/E4 combination has the most risk.
• E2 allele increases likelihood of having Alzheimer's. E2/E3 combination has the most risk.
• People with different alleles for APOE have a higher risk for Alzheimer's.

The graph shows serotonin levels on two groups of mice. The "KO" group mice have depression (artificially induced for the study) and the "Con" group is the control group.

What is a conclusion that can be drawn from this graph?

• Mice with depression do not produce any serotonin.
• Mice with depression produce the same amounts of serotonin as other mice.
• Mice with depression produce more serotonin than other mice.
• Mice with depression produce less serotonin than other mice.

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• Section URL: https://openstax.org/books/biology-ap-courses/pages/26-critical-thinking-questions

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12.1 Structure and Function of the Nervous System

Learning objectives.

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

Relate the anatomical structures to the basic functions of the nervous system.

• Identify the anatomical and functional divisions of the nervous system
• List the basic functions of the nervous system

The Central and Peripheral Nervous Systems

The picture you have in your mind of the nervous system probably includes the brain , the nervous tissue contained within the cranium, and the spinal cord , the extension of nervous tissue within the vertebral column. Additionally, the nervous tissue   that reach out from the brain and spinal cord to the rest of the body ( nerves)  are also part of the nervous system. We can anatomically divide the nervous system into two major regions: the  central nervous system (CNS) is the brain and spinal cord, the peripheral nervous system (PNS) is the nerves ( Figure 12.1.1 ). The brain is contained within the cranial cavity of the skull, and the spinal cord is contained within the vertebral canal of the vertebral column. The peripheral nervous system is so named because it is in the periphery—meaning beyond the brain and spinal cord.

Functional Divisions of the Nervous System

In addition to the anatomical divisions listed above, the nervous system can also be divided on the basis of its functions. The nervous system is involved in receiving information about the environment around us (sensory functions, sensation ) and generating responses to that information (motor functions, responses ) and coordinating the two ( integration ).

Sensation . Sensation refers to receiving information about the environment, either what is happening outside (ie: heat from the sun) or inside the body (ie: heat from muscle activity). These sensations are known as stimuli (singular = stimulus ) and different sensory receptors are responsible for detecting different stimuli. Sensory information travels towards the CNS through the PNS nerves in the specific division known as the afferent (sensory) branch of the PNS. When information arises from sensory receptors in the skin, skeletal muscles, or joints, it is transmitted to the CNS using somatic sensory neurons; when information arises from sensory receptors in the blood vessels or internal organs, it is transmitted to the CNS using visceral sensory neurons.

Response. The nervous system produces a response in effector organs (such as muscles or glands) due to the sensory stimuli. The motor ( efferent ) branch of the PNS carries signals away from the CNS to the effector organs. When the effector organ is a skeletal muscle, the neuron carrying the information is called a somatic motor neuron; when the effector organ is cardiac or smooth muscle or glandular tissue, the neuron carrying the information is called an autonomic motor neuron. Voluntary responses are governed by somatic motor neurons and involuntary responses are governed by the autonomic motor neurons, which are discussed in the next section.

Integration . Stimuli that are detected by sensory structures are communicated to the nervous system where information is processed. In the CNS, information from some stimuli is compared with, or integrated with, information from other stimuli or memories of previous stimuli. Then, a motor neuron is activated to initiate a response from the effector organ. This process during which sensory information is processed and a motor response generated is called integration (see Figure 12.1.2 below).

Chapter Review

The nervous system can be separated into divisions on the basis of anatomy and physiology. The anatomical divisions are the central and peripheral nervous systems. The CNS is the brain and spinal cord. The PNS is everything else and includes afferent and efferent branches with further subdivisions for somatic, visceral and autonomic function. Functionally, the nervous system can be divided into those regions that are responsible for sensation, those that are responsible for integration, and those that are responsible for generating responses.

Review Questions

Critical thinking questions.

1. What responses are generated by the nervous system when you run on a treadmill? Include an example of each type of tissue that is under nervous system control.

2. When eating food, what anatomical and functional divisions of the nervous system are involved in the perceptual experience?

Answers for Critical Thinking Questions

• Running on a treadmill involves contraction of the skeletal muscles in the legs (efferent somatic motor), increase in contraction of the cardiac muscle of the heart (efferent autonomic motor), and the production and secretion of sweat in the skin to stay cool (sensation of temp = afferent visceral sensory, sweat gland activation = efferent autonomic motor).
• The perceptual experience of eating food refers to tasting food, both in terms of flavors and texture. The neurons responsible for sensing taste are afferent somatic neurons of the PNS.

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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.

The Nervous System and Nervous Tissue

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• 1 - Introduction
• 2 - 12.1 Basic Structure and Function of the Nervous System
• 3 - Nervous Tissue
• 4 - The Function of Nervous Tissue
• 5 - The Action Potential
• 6 - Communication Between Neurons
• 7 - Key Terms
• 8 - Chapter Review
• 9 - Interactive Link Questions
• 10 - Review Questions
• 11 - Critical Thinking Questions
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Critical Thinking Questions

What responses are generated by the nervous system when you run on a treadmill? Include an example of each type of tissue that is under nervous system control.

When eating food, what anatomical and functional divisions of the nervous system are involved in the perceptual experience?

Multiple sclerosis is a demyelinating disease affecting the central nervous system. What type of cell would be the most likely target of this disease? Why?

Which type of neuron, based on its shape, is best suited for relaying information directly from one neuron to another? Explain why.

Sensory fibers, or pathways, are referred to as “afferent.” Motor fibers, or pathways, are referred to as “efferent.” What can you infer about the meaning of these two terms (afferent and efferent) in a structural or anatomical context?

If a person has a motor disorder and cannot move their arm voluntarily, but their muscles have tone, which motor neuron—upper or lower—is probably affected? Explain why.

What does it mean for an action potential to be an “all or none” event?

The conscious perception of pain is often delayed because of the time it takes for the sensations to reach the cerebral cortex. Why would this be the case based on propagation of the axon potential?

If a postsynaptic cell has synapses from five different cells, and three cause EPSPs and two of them cause IPSPs, give an example of a series of depolarizations and hyperpolarizations that would result in the neuron reaching threshold.

Why is the receptor the important element determining the effect a neurotransmitter has on a target cell?