Question 1

Which of the following statements best describes the role of the sarcolemma in skeletal muscle contraction?

Accepted Answer

It is the plasma membrane that allows selective permeability, enabling the reversal of charge necessary for muscle contraction.

Question 2

A patient is experiencing muscle fatigue after intense exercise. Which metabolic pathway is primarily responsible for the rapid but inefficient production of ATP under these conditions?

Accepted Answer

Glycolysis in the cytosol

Question 3

Which protein blocks the myosin binding site on actin in a resting muscle fiber?

Accepted Answer

Tropomyosin

Question 4

During the propagation of an action potential along a neuron, which ion is primarily responsible for depolarization of the membrane?

Accepted Answer

Sodium ($$Na^+)$$

Question 5

Which type of muscle tissue is found in the walls of hollow internal structures such as the stomach and intestines, and is under involuntary control?

Accepted Answer

Smooth muscle

Question 6

A muscle fiber is stimulated by a motor neuron. Which sequence correctly describes the steps leading to contraction?

Accepted Answer

ACh release → Na$$^+$$ influx → action potential → Ca$$^{2+}$$ release from SR → cross-bridge formation

Question 7

Which of the following best explains why the A band width remains unchanged during muscle contraction?

Accepted Answer

The thick filaments (myosin) do not change length during contraction.

Question 8

A patient with Bell's palsy presents with temporary paralysis of facial muscles. Which cranial nerve is most likely affected?

Accepted Answer

Cranial nerve VII (Facial)

Question 9

Which of the following muscle fiber types is best suited for long-distance running due to its resistance to fatigue and reliance on aerobic metabolism?

Accepted Answer

Slow fibers

Question 10

What is the primary function of the sodium-potassium pump in maintaining the resting membrane potential?

Accepted Answer

It exports 3 $$Na^+$$ ions and imports 2 $$K^+$$ ions, maintaining an uneven distribution of charges.

Question 11

Which connective tissue layer surrounds individual muscle fibers and contains stem cells for repair?

Accepted Answer

Endomysium

Question 12

A muscle contraction in which tension rises but the muscle length does not change is called:

Accepted Answer

Isometric contraction

Question 13

Which of the following is a regulatory protein that binds calcium ions to initiate muscle contraction?

Accepted Answer

Troponin

Question 14

Which structure in a neuron is primarily responsible for carrying information toward other cells?

Accepted Answer

Axon

Question 15

Which of the following best describes the function of astrocytes in the central nervous system?

Accepted Answer

They form the blood-brain barrier and regulate ion and nutrient concentrations.

Question 16

Which of the following is true regarding the organization of skeletal muscle fascicles?

Accepted Answer

Convergent muscles have fascicles that meet at a single point.

Question 17

Which of the following best explains why motor units in the hands and face are smaller than those in the thighs?

Accepted Answer

Smaller motor units allow for finer control of movement.

Question 18

Which of the following equations correctly represents the net movement of ions by the sodium-potassium pump during one cycle?

Accepted Answer

$$3\ Na^+_{out} : 2\ K^+_{in}$$

Question 19

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

Accepted Answer

It stores and releases calcium ions required for contraction.

Question 20

A muscle fiber is unable to contract because ATP is depleted. Which step of the contraction cycle is directly affected?

Accepted Answer

Myosin heads cannot detach from actin, preventing relaxation.

Muscle Tissue Structure and Function: Study Notes for Anatomy & Physiology

Guida di studio - Domande di pratica

Study guide - Flashcard