Question 1

Which of the following adaptations is most likely to occur in skeletal muscle fibers as a result of regular aerobic (endurance) exercise?

Accepted Answer

Increase in the number of mitochondria

Question 2

During resistance (strength) training, which cellular change primarily accounts for the increase in muscle size?

Accepted Answer

Increase in the number of myofibrils and myofilaments

Question 3

A patient is immobilized in a cast for several weeks. Which of the following best describes the changes that occur in the affected skeletal muscle?

Accepted Answer

Muscle atrophy due to loss of neural stimulation

Question 4

Which of the following is a unique feature of smooth muscle compared to skeletal muscle?

Accepted Answer

Presence of dense bodies instead of Z discs

Question 5

Which statement best explains why smooth muscle can maintain contraction for prolonged periods with minimal energy expenditure?

Accepted Answer

Smooth muscle myosin ATPases are slower and latch-bridge mechanisms allow sustained contraction

Question 6

Which of the following best describes the mechanism by which smooth muscle contraction is initiated?

Accepted Answer

Calcium binds to calmodulin, which activates myosin light chain kinase

Question 7

A drug that blocks gap junctions in smooth muscle would most likely impair which of the following?

Accepted Answer

The spread of depolarization between adjacent smooth muscle cells

Question 8

Which of the following equations best represents the relationship between force (F), cross-sectional area (A), and muscle tension (T) in skeletal muscle?

Accepted Answer

$$F = T 	imes A$$

Question 9

Which of the following is true regarding the organization of smooth muscle in the walls of hollow organs?

Accepted Answer

It is arranged in two layers: longitudinal and circular, oriented at right angles to each other

Question 10

Which of the following best explains why smooth muscle can function over a wide range of lengths?

Accepted Answer

The stress-relaxation response allows smooth muscle to adapt to stretch and maintain contractility

Question 11

Which of the following is a characteristic of multiunit smooth muscle but NOT single-unit (unitary) smooth muscle?

Accepted Answer

Each muscle fiber is innervated and contracts independently

Question 12

A patient with a disorder affecting myosin light chain kinase (MLCK) would most likely experience which of the following symptoms?

Accepted Answer

Impaired smooth muscle contraction

Question 13

Which of the following best describes the role of calmodulin in smooth muscle contraction?

Accepted Answer

It binds calcium and activates myosin light chain kinase

Question 14

Which of the following is a key difference between the sources of calcium for contraction in smooth muscle versus skeletal muscle?

Accepted Answer

Smooth muscle relies more on extracellular calcium influx

Question 15

Which of the following best explains why smooth muscle contraction is slower to initiate but can be sustained longer than skeletal muscle contraction?

Accepted Answer

Smooth muscle uses a latch-bridge mechanism and slower ATPase activity

Question 16

Which of the following best describes the effect of neurotransmitters on smooth muscle contraction?

Accepted Answer

The effect depends on the type of neurotransmitter and receptor present

Question 17

A patient is given a drug that inhibits myosin phosphatase in smooth muscle. What is the most likely effect?

Accepted Answer

Prolonged contraction due to delayed relaxation

Question 18

Which of the following best describes the arrangement of contractile filaments in smooth muscle?

Accepted Answer

Filaments are arranged diagonally, causing a corkscrew contraction

Question 19

Which of the following best explains why smooth muscle can contract even when stretched to twice its resting length?

Accepted Answer

The stress-relaxation response allows adaptation to stretch

Question 20

Which of the following is a characteristic of single-unit (unitary) smooth muscle?

Accepted Answer

Cells are electrically coupled by gap junctions and contract as a unit

Muscle Physiology: Exercise, Health, and Smooth Muscle Structure

Guida di studio - Domande di pratica

Study guide - Flashcard