Q: During the depolarization phase of an action potential, which ion channel opens and what is the direction of ion movement?

Voltage-gated Na\textsuperscript{+} channels open, Na\textsuperscript{+} moves into the cell.

Question 1

Which of the following best describes the role of Schwann cells in the peripheral nervous system (PNS)?

Accepted Answer

They form the myelin sheath around axons, increasing conduction velocity.

Question 2

A patient presents with muscle weakness and delayed reflexes. Which type of glial cell dysfunction in the CNS could most likely explain these symptoms?

Accepted Answer

Oligodendrocyte

Question 3

During the depolarization phase of an action potential, which ion channel opens and what is the direction of ion movement?

Accepted Answer

Voltage-gated Na	extsuperscript{+} channels open, Na	extsuperscript{+} moves into the cell.

Question 4

Which equation correctly represents the calculation of conduction velocity ($$v) in a $$myelinated axon, given the length ($$d) $$and time ($$t) $$for an action potential to travel?

Accepted Answer

$$v = \dfrac{d}{t}$$

Question 5

Which of the following best explains why myelinated axons conduct impulses faster than unmyelinated axons?

Accepted Answer

Myelination allows saltatory conduction, where action potentials jump between nodes of Ranvier.

Question 6

A muscle fiber is stimulated and undergoes contraction. Which of the following events occurs first in the sliding filament theory?

Accepted Answer

Calcium ions bind to troponin, causing tropomyosin to move and expose binding sites on actin.

Question 7

Which type of muscle tissue is responsible for voluntary movements such as walking?

Accepted Answer

Skeletal muscle

Question 8

A patient is unable to maintain posture and experiences rapid muscle fatigue. Which functional characteristic of muscle tissue is most likely impaired?

Accepted Answer

Endurance (related to muscle tone and resistance to fatigue)

Question 9

Which of the following best describes the role of ATP in muscle contraction?

Accepted Answer

ATP hydrolysis provides energy for the myosin head to perform the power stroke.

Question 10

Which of the following is a correct sequence of events in the generation of an action potential?

Accepted Answer

Resting potential $$\rightarrow$$ depolarization $$\rightarrow$$ repolarization $$\rightarrow$$ hyperpolarization

Question 11

Which of the following best describes the difference between graded local potentials and action potentials?

Accepted Answer

Graded potentials can summate and decrease with distance, while action potentials are propagated without decrement.

Question 12

Which of the following is a function of astrocytes in the central nervous system?

Accepted Answer

Providing structural support and regulating the blood-brain barrier

Question 13

Which of the following best explains the effect of increasing the diameter of an axon on the speed of nerve impulse conduction?

Accepted Answer

It increases the speed by reducing internal resistance to ion flow.

Question 14

Which of the following is a correct classification of neurons based on structure?

Accepted Answer

Bipolar neurons have one axon and one dendrite.

Question 15

A patient has damage to the autonomic nervous system. Which of the following functions is most likely to be affected?

Accepted Answer

Regulation of heart rate and digestion

Question 16

Which of the following best describes the function of the sarcoplasmic reticulum in skeletal muscle fibers?

Accepted Answer

It stores and releases calcium ions necessary for muscle contraction.

Question 17

Which of the following is true regarding the refractory period of an action potential?

Accepted Answer

It prevents the backward propagation of the action potential.

Question 18

Which of the following is a correct description of the role of the neuromuscular junction?

Accepted Answer

It is the site where a motor neuron communicates with a muscle fiber to initiate contraction.

Question 19

Which of the following best explains the difference between isotonic and isometric muscle contractions?

Accepted Answer

Isotonic contractions involve muscle changing length with constant tension, while isometric contractions involve tension without length change.

Comprehensive Study Notes: Nervous System and Muscles & Muscle Tissue

Study Guide - Practice Questions

Study Guide - Flashcards