$$\mathrm{ATP} + \mathrm{H_2O} \rightarrow \mathrm{ADP} + \mathrm{P_i} + \text{energy}$$

Question 1

Which of the following best describes the role of calcium ions ($$\mathrm{Ca$$^{2+}$$}) in $$skeletal muscle contraction?

Accepted Answer

Calcium ions bind to troponin, causing tropomyosin to move and expose active sites on actin.

Question 2

A patient presents with muscle weakness and limp, floppy muscles. Which condition is most likely responsible?

Accepted Answer

Flaccid paralysis

Question 3

Which muscle type is responsible for the rhythmic contractions that propel blood through the circulatory system?

Accepted Answer

Cardiac muscle

Question 4

During the sliding filament model of muscle contraction, what happens after myosin heads bind to actin?

Accepted Answer

Myosin heads bend, pulling thin filaments toward the center of the sarcomere.

Question 5

Which equation best represents the ATP hydrolysis that provides energy for muscle contraction?

Accepted Answer

$$\mathrm{ATP} + \mathrm{H_2O} ightarrow \mathrm{ADP} + \mathrm{P_i} + 	ext{energy}$$

Question 6

Which structure in the muscle fiber is responsible for storing and releasing calcium ions during contraction?

Accepted Answer

Sarcoplasmic reticulum

Question 7

A marathon runner's muscles produce heat as a byproduct of contraction. What physiological principle does this illustrate?

Accepted Answer

Negative feedback for body temperature regulation

Question 8

Which of the following is NOT a characteristic shared by all muscle tissue types?

Accepted Answer

Ability to generate nerve impulses

Question 9

What is the primary neurotransmitter released at the neuromuscular junction to initiate muscle contraction?

Accepted Answer

Acetylcholine (ACh)

Question 10

Which type of muscle contraction occurs when muscle tension increases but muscle length remains unchanged?

Accepted Answer

Isometric contraction

Question 11

A person is unable to maintain upright posture due to reduced muscle tone. Which term best describes this condition?

Accepted Answer

Flaccidity

Question 12

Which protein forms the bulk of the thick filaments in a sarcomere?

Accepted Answer

Myosin

Question 13

What is the smallest contractile unit of a skeletal muscle fiber?

Accepted Answer

Sarcomere

Question 14

Which muscle type is under voluntary control and is responsible for movement of the skeleton?

Accepted Answer

Skeletal muscle

Question 15

During muscle contraction, which event directly follows the release of calcium ions from the sarcoplasmic reticulum?

Accepted Answer

Calcium binds to troponin, causing tropomyosin to shift and expose actin sites.

Question 16

Which of the following best explains why cardiac muscle cannot produce tetanus?

Accepted Answer

Cardiac muscle has a long refractory period preventing rapid repeated contractions.

Question 17

Which equation represents the relationship between force ($$F$$), mass ($$m$$), and acceleration ($$a) $$relevant to muscle movement?

Accepted Answer

$$F = m 	imes a$$

Question 18

A patient with spastic paralysis would most likely exhibit which of the following symptoms?

Accepted Answer

Muscles that are rigid and have increased tone

Question 19

Which of the following is NOT a function of muscle tissue?

Accepted Answer

Storage of genetic information

Question 20

Which process is responsible for the continual, partial contraction of muscles that helps maintain posture?

Accepted Answer

Muscle tone

Muscle Tissue: Structure, Function, and Contraction Mechanisms

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