$$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{ADP} + \mathrm{P}_i + \text{energy}$$

Question 1

Which connective tissue sheath surrounds an individual muscle fiber (cell) in skeletal muscle?

Accepted Answer

Endomysium

Question 2

During muscle contraction, which event directly triggers the exposure of myosin binding sites on actin?

Accepted Answer

Binding of calcium ions to troponin

Question 3

Which of the following best describes the role of T tubules in skeletal muscle contraction?

Accepted Answer

They conduct action potentials deep into the muscle fiber

Question 4

A patient is unable to relax their muscles after contraction. Which process is most likely impaired?

Accepted Answer

Reuptake of calcium ions into the sarcoplasmic reticulum

Question 5

Which of the following is TRUE regarding the sliding filament model of muscle contraction?

Accepted Answer

Thin filaments slide past thick filaments, increasing overlap

Question 6

Which phase of a muscle twitch corresponds to the time when excitation-contraction coupling is occurring, but no tension is yet measurable?

Accepted Answer

Latent period

Question 7

A muscle is stimulated repeatedly with increasing voltage. At a certain point, no further increase in tension is observed. This point is known as:

Accepted Answer

Maximal stimulus

Question 8

Which of the following best explains why lactic acid accumulates in muscle during intense exercise?

Accepted Answer

Oxygen delivery is impaired, leading to anaerobic glycolysis

Question 9

Which of the following equations correctly represents the hydrolysis of ATP during muscle contraction?

Accepted Answer

$$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} ightarrow \mathrm{ADP} + \mathrm{P}_i + 	ext{energy}$$

Question 10

Which of the following is a characteristic unique to cardiac muscle tissue?

Accepted Answer

It is found only in the heart and contracts at a steady rate set by a pacemaker

Question 11

Which of the following best describes the function of acetylcholinesterase at the neuromuscular junction?

Accepted Answer

It breaks down acetylcholine, terminating the signal

Question 12

Which of the following is TRUE regarding isometric muscle contractions?

Accepted Answer

Tension increases but the muscle does not change length

Question 13

Which protein directly binds calcium ions to initiate skeletal muscle contraction?

Accepted Answer

Troponin

Question 14

A patient with muscular dystrophy experiences muscle weakness due to:

Accepted Answer

Muscle fibers being replaced by fat and connective tissue

Question 15

Which of the following best explains the 'staircase effect' (treppe) observed in muscle contraction?

Accepted Answer

Contractions increase due to increased Ca2+ availability and enzyme efficiency

Question 16

Which of the following is a function of smooth muscle but NOT skeletal muscle?

Accepted Answer

Propelling substances through internal body channels

Question 17

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

Accepted Answer

It stores and releases calcium ions

Question 18

Which of the following is TRUE regarding the arrangement of myofilaments in a sarcomere?

Accepted Answer

Thin filaments are anchored to the Z disc

Question 19

Which of the following best explains why muscles generate heat during activity?

Accepted Answer

Only 40% of energy from ATP is used for work; the rest is released as heat

Question 20

Which of the following is a correct sequence of events in excitation-contraction coupling in skeletal muscle?

Accepted Answer

Action potential travels along sarcolemma → Ca2+ released from SR → Ca2+ binds to troponin → Tropomyosin moves → Myosin binds actin

Muscles and Muscle Tissue: Structure and Function

Study Guide - Practice Questions