Question 1

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

Accepted Answer

It is the basic contractile unit of muscle fibers, where actin and myosin interact to produce contraction.

Question 2

During the excitation-contraction coupling process, what is the primary effect of calcium ions ($$\mathrm{Ca$$^{2+}$$}) $$released from the sarcoplasmic reticulum?

Accepted Answer

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

Question 3

Which equation correctly represents the net ATP yield from aerobic metabolism of one glucose molecule in skeletal muscle?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$} + 6\mathrm{O_2$} \rightarrow 6\mathrm{CO_2$} + 6\mathrm{H_2O} + 36\mathrm{ATP}$$

Question 4

A patient is experiencing muscle fatigue after prolonged exercise. Which metabolic pathway is most likely responsible for the rapid depletion of ATP in this scenario?

Accepted Answer

Direct phosphorylation by creatine phosphate

Question 5

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

Accepted Answer

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

Question 6

Which of the following is a correct description of the events during an action potential in a neuron?

Accepted Answer

Depolarization occurs as $$\mathrm{Na^+}$$ ions enter the cell, followed by repolarization as $$\mathrm{K^+}$$ ions exit.

Question 7

If a neurotransmitter opens chloride ($$\mathrm{Cl^-}) $$channels on the postsynaptic membrane, what is the likely effect?

Accepted Answer

It will hyperpolarize the postsynaptic cell, making it less likely to fire an action potential.

Question 8

Which of the following best describes the function of an agonist muscle during movement?

Accepted Answer

It is the primary muscle responsible for producing a specific movement.

Question 9

A neuron receives simultaneous excitatory and inhibitory inputs. If the net effect is a membrane potential of $$-80\ \mathrm{mV}$$, what is the likely outcome?

Accepted Answer

The neuron will remain at rest, as the membrane is hyperpolarized.

Question 10

Which of the following is NOT a function of the nervous system?

Accepted Answer

Production of red blood cells

Question 11

Which type of neuron is most likely to be found in the retina of the human eye?

Accepted Answer

Bipolar neuron

Question 12

A patient is given a drug that blocks voltage-gated sodium channels. What effect will this have on neuronal action potentials?

Accepted Answer

Action potentials will be inhibited, preventing nerve signal transmission.

Question 13

Which of the following best describes the effect of GABA (gamma-aminobutyric acid) on postsynaptic neurons?

Accepted Answer

It acts as an inhibitory neurotransmitter, causing hyperpolarization.

Question 14

Which of the following correctly matches the muscle fiber type with its characteristic?

Accepted Answer

Type I fibers: slow-twitch, high endurance

Question 15

Which process is directly responsible for the return of the sarcolemma to its resting membrane potential after an action potential?

Accepted Answer

Active transport of $$\mathrm{Na^+}$$ and $$\mathrm{K^+} by $$the sodium-potassium pump ($$3\mathrm{Na^+}$$ out, $$2\mathrm{K^+} in)$$

Question 16

Which of the following scenarios would most likely result in muscle tetanus?

Accepted Answer

High-frequency stimulation causing sustained contraction without relaxation

Question 17

A patient is diagnosed with myasthenia gravis, an autoimmune disorder affecting the neuromuscular junction. Which structure is primarily targeted by the immune system?

Accepted Answer

Acetylcholine receptors on the motor end plate

Question 18

Which of the following best explains the effect of increasing extracellular potassium ($$\mathrm{K^+}) $$concentration on the resting membrane potential of a neuron?

Accepted Answer

It makes the resting membrane potential less negative (depolarization).

Question 19

Which organizational level of muscle is correctly matched with its description?

Accepted Answer

Muscle fiber: a single muscle cell

Question 20

A patient is given a drug that blocks acetylcholinesterase at the neuromuscular junction. What is the expected effect on muscle contraction?

Accepted Answer

Muscle contraction will be prolonged due to excess acetylcholine in the synaptic cleft.

Muscle and Nervous Tissue: Study Guide for Anatomy & Physiology

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