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Anatomy & Physiology: Nervous System Physiology Study Guide

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Q1. The CNS consists of billions of neurons in the _____________ and ______________

Background

Topic: Central Nervous System (CNS) Organization

This question is testing your knowledge of the main anatomical components of the CNS.

Key Terms:

  • Central Nervous System (CNS): The part of the nervous system consisting of the brain and spinal cord.

  • Neuron: A nerve cell that transmits electrical and chemical signals in the nervous system.

Step-by-Step Guidance

  1. Recall the two main structures that make up the CNS.

  2. Think about where the majority of neurons are located within the body, specifically in the context of the CNS.

  3. Fill in the blanks with the correct anatomical terms.

Try solving on your own before revealing the answer!

Final Answer: brain and spinal cord

The CNS consists of billions of neurons in the brain and spinal cord.

Q2. What is a tract?

Background

Topic: CNS Pathways

This question is about the terminology used to describe bundles of axons in the CNS.

Key Terms:

  • Tract: A bundle of nerve fibers (axons) in the CNS that have a common origin and destination.

  • Axon: The long, threadlike part of a neuron that transmits impulses away from the cell body.

Step-by-Step Guidance

  1. Recall the difference between a nerve and a tract.

  2. Think about where the term "tract" is used (CNS or PNS?).

  3. Define what a tract is in your own words, focusing on its structure and function.

Try solving on your own before revealing the answer!

Final Answer: A tract is a bundle of axons in the CNS that carry similar information to or from specific regions.

Tracts are analogous to nerves in the PNS, but the term "tract" is reserved for the CNS.

Q3. Axons carry impulses only in one direction. What type of information is carried by: Ascending tracts? Descending tracts?

Background

Topic: CNS Pathways and Directionality

This question tests your understanding of the functional organization of the spinal cord and brain pathways.

Key Terms:

  • Ascending tracts: Pathways that carry sensory information up the spinal cord to the brain.

  • Descending tracts: Pathways that carry motor commands from the brain down the spinal cord to the body.

Step-by-Step Guidance

  1. Recall the direction of information flow in ascending and descending tracts.

  2. Think about whether each tract is associated with sensory or motor information.

  3. Fill in the type of information each tract carries.

Try solving on your own before revealing the answer!

Final Answer:

Ascending tracts: Carry sensory information to the brain.

Descending tracts: Carry motor commands from the brain to the body.

Q4. What does the PNS consist of?

Background

Topic: Peripheral Nervous System (PNS) Organization

This question is about the anatomical components of the PNS.

Key Terms:

  • Peripheral Nervous System (PNS): The part of the nervous system outside the brain and spinal cord.

  • Nerve: A bundle of axons in the PNS.

Step-by-Step Guidance

  1. Recall what structures are included in the PNS.

  2. Think about the difference between the CNS and PNS in terms of location and function.

  3. List the main components that make up the PNS.

Try solving on your own before revealing the answer!

Final Answer: The PNS consists of all nerves and ganglia outside the brain and spinal cord.

This includes cranial nerves, spinal nerves, and peripheral ganglia.

Q5. What is a nerve?

Background

Topic: Nervous System Terminology

This question is about the definition and structure of a nerve in the PNS.

Key Terms:

  • Nerve: A bundle of axons (nerve fibers) in the PNS, often containing both sensory and motor fibers.

  • Axon: The long projection of a neuron that transmits impulses.

Step-by-Step Guidance

  1. Recall the difference between a nerve and a tract.

  2. Think about the composition of a nerve (what types of fibers can it contain?).

  3. Define a nerve in your own words, focusing on its structure and function.

Try solving on your own before revealing the answer!

Final Answer: A nerve is a bundle of axons in the PNS, often containing both sensory and motor fibers.

Nerves transmit information between the CNS and the rest of the body.

Q6. What type of information is carried by: Afferent nerves? Efferent nerves? Autonomic efferent? Somatic efferent?

Background

Topic: Functional Classification of Nerves

This question tests your understanding of the direction and type of information carried by different nerve fibers.

Key Terms:

  • Afferent nerves: Carry sensory information toward the CNS.

  • Efferent nerves: Carry motor commands away from the CNS.

  • Autonomic efferent: Motor fibers that control involuntary functions (smooth muscle, cardiac muscle, glands).

  • Somatic efferent: Motor fibers that control voluntary skeletal muscles.

Step-by-Step Guidance

  1. Recall the meaning of "afferent" and "efferent." (Afferent = toward CNS, Efferent = away from CNS)

  2. Think about what types of information each carries (sensory or motor).

  3. Differentiate between autonomic and somatic efferent fibers.

  4. Fill in the type of information for each category.

Try solving on your own before revealing the answer!

Final Answer:

Afferent nerves: Carry sensory information to the CNS.

Efferent nerves: Carry motor commands from the CNS to effectors.

Autonomic efferent: Carry involuntary motor commands to smooth muscle, cardiac muscle, and glands.

Somatic efferent: Carry voluntary motor commands to skeletal muscles.

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