$$E = \frac{RT}{zF} \ln \left( \frac{[\text{ion}]_{\text{outside}}}{[\text{ion}]_{\text{inside}}} \right)$$

Question 1

Which of the following best describes the difference in control between skeletal, cardiac, and smooth muscle tissue?

Accepted Answer

Skeletal muscle is voluntary, cardiac muscle is involuntary, and smooth muscle is involuntary.

Question 2

During muscle contraction, which protein does calcium bind to, initiating the exposure of myosin binding sites on actin?

Accepted Answer

Troponin

Question 3

Which of the following best explains the role of the sarcoplasmic reticulum in skeletal muscle contraction?

Accepted Answer

It stores and releases calcium ions ($$\mathrm{Ca$$^{2+}$$}) $$necessary for contraction.

Question 4

A patient is experiencing muscle fatigue after intense exercise. Which ATP production pathway is most likely being used at this point?

Accepted Answer

Anaerobic respiration

Question 5

Which of the following correctly matches the muscle tissue type with its cell shape?

Accepted Answer

Skeletal: long, cylindrical; Cardiac: short, branched; Smooth: spindle-shaped

Question 6

Which statement best describes the function of the sodium-potassium pump in maintaining the resting membrane potential?

Accepted Answer

It pumps 3 $$\mathrm{Na^+}$$ ions out of the cell and 2 $$\mathrm{K^+}$$ ions in, maintaining a negative charge inside.

Question 7

During the cross-bridge cycle in muscle contraction, what is the direct role of ATP?

Accepted Answer

ATP hydrolysis energizes the myosin head, allowing it to bind to actin and perform the power stroke.

Question 8

Which of the following best describes the organization of a sarcomere?

Accepted Answer

It is the region between two Z discs and contains thick and thin filaments.

Question 9

A nerve impulse arrives at the neuromuscular junction (NMJ). What is the first event that occurs to initiate muscle contraction?

Accepted Answer

Acetylcholine (ACh) is released from the motor neuron and binds to receptors on the muscle cell membrane.

Question 10

Which of the following is TRUE regarding graded potentials and action potentials?

Accepted Answer

Graded potentials can be depolarizing or hyperpolarizing, while action potentials are always depolarizing and self-propagating.

Question 11

Which equation correctly represents the Nernst equation for calculating the equilibrium potential of an ion across a membrane?

Accepted Answer

$$E = \frac{RT}{zF} \ln \left( \frac{[	ext{ion}]_{	ext{outside}}}{[	ext{ion}]_{	ext{inside}}} ight)$$

Question 12

Which of the following best explains the 'all-or-none' phenomenon of action potentials?

Accepted Answer

An action potential is generated only if the stimulus is strong enough to reach threshold; otherwise, no action potential occurs.

Question 13

Which of the following is a function unique to muscle tissue, not shared by other tissue types?

Accepted Answer

Contractility

Question 14

During the refractory period of an action potential, which statement is correct?

Accepted Answer

A second action potential cannot be generated until the membrane potential returns to resting and Na+ channels reset.

Question 15

Which of the following best describes the effect of myelination on nerve conduction?

Accepted Answer

Myelination allows action potentials to jump rapidly from node to node, increasing conduction speed.

Question 16

Which of the following correctly describes the sequence of events in excitation-contraction coupling in skeletal muscle?

Accepted Answer

Action potential travels down the T-tubule, causing release of calcium from the sarcoplasmic reticulum.

Question 17

Which of the following is TRUE regarding the difference between the absolute and relative refractory periods?

Accepted Answer

During the relative refractory period, a stronger-than-normal stimulus can generate another action potential.

Question 18

A muscle fiber is at rest. Which band in the sarcomere will change length when the muscle contracts?

Accepted Answer

I band

Question 19

Which of the following best describes the role of voltage-gated sodium channels during the initiation of an action potential?

Accepted Answer

They open in response to depolarization, allowing $$\mathrm{Na^+} to $$enter the cell and further depolarize the membrane.

Muscle Tissue and Action Potential: Structured Study Notes for Anatomy & Physiology

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