Question 1

Which of the following best describes the role of acetylcholine (ACh) at the neuromuscular junction during muscle contraction?

Accepted Answer

ACh is released from the motor neuron and binds to receptors on the muscle fiber, triggering an action potential.

Question 2

During excitation-contraction coupling, which event directly leads to the release of calcium ions from the sarcoplasmic reticulum?

Accepted Answer

Propagation of the action potential along the T-tubules

Question 3

A patient is experiencing muscle weakness due to a defect in the voltage-gated sodium channels of their muscle fibers. Which step in the muscle contraction process is most likely impaired?

Accepted Answer

Generation and propagation of the action potential along the sarcolemma

Question 4

Which equation correctly represents the hydrolysis of ATP during muscle contraction?

Accepted Answer

$$ATP \rightarrow ADP + Pi + energy$$

Question 5

Which of the following factors most directly increases the force of muscle contraction?

Accepted Answer

The number of cross bridges formed between actin and myosin

Question 6

A muscle fiber is unable to relax after contraction. Which of the following is the most likely cause?

Accepted Answer

Impaired reuptake of calcium ions into the sarcoplasmic reticulum

Question 7

Which of the following best explains why fast glycolytic muscle fibers fatigue more quickly than slow oxidative fibers?

Accepted Answer

Fast glycolytic fibers have fewer mitochondria and rely primarily on anaerobic metabolism.

Question 8

Which of the following is a correct description of a motor unit?

Accepted Answer

A motor unit consists of a single motor neuron and all the muscle fibers it innervates.

Question 9

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

Accepted Answer

They produce myelin sheaths around axons, increasing the speed of nerve impulse conduction.

Question 10

Which of the following ions is primarily responsible for the depolarization phase of the action potential in neurons?

Accepted Answer

Sodium (Na\^+)

Question 11

A neuron is classified as multipolar. Which of the following best describes its structure?

Accepted Answer

It has one axon and two or more dendrites.

Question 12

Which of the following equations correctly represents the Nernst equation for calculating the equilibrium potential of an ion?

Accepted Answer

$$E = \frac{RT}{zF} \ln \left( \frac{[ion]_{out}}{[ion]_{in}} \right)$$

Question 13

Which of the following best describes the effect of myelination on the conduction velocity of action potentials?

Accepted Answer

Myelination increases conduction velocity by allowing saltatory conduction between nodes of Ranvier.

Question 14

Which of the following is true regarding the difference between EPSPs and IPSPs?

Accepted Answer

EPSPs depolarize the postsynaptic membrane, while IPSPs hyperpolarize it.

Question 15

A patient presents with muscle fatigue after prolonged exercise. Which of the following is the most likely physiological cause?

Accepted Answer

Accumulation of lactic acid in muscle fibers

Question 16

Which of the following best explains why the resting membrane potential of a neuron is typically negative?

Accepted Answer

The sodium-potassium pump actively transports more sodium out than potassium in, creating a net negative charge inside.

Question 17

Which of the following best describes the role of voltage-gated calcium channels at the axon terminal during synaptic transmission?

Accepted Answer

They allow calcium to enter the axon terminal, triggering the release of neurotransmitters into the synaptic cleft.

Question 18

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

Accepted Answer

Regulating the extracellular environment and maintaining the blood-brain barrier

Question 19

Which of the following best describes the difference between the CNS and PNS?

Accepted Answer

The CNS consists of the brain and spinal cord, while the PNS consists of cranial and spinal nerves.

Muscle Physiology and Nervous System Fundamentals: Study Guide

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