Q: Which equation represents the direct phosphorylation of ADP by creatine phosphate during muscle contraction?

$$\text{Creatine phosphate} + \text{ADP} \rightarrow \text{Creatine} + \text{ATP}$$

Question 1

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

Accepted Answer

NMJ events → muscle fiber excitation → excitation-contraction coupling → cross bridge cycling

Question 2

During muscle contraction, which structural change occurs within the sarcomere?

Accepted Answer

The Z discs move closer together, and the H zone disappears.

Question 3

A patient presents with muscle weakness and frequent falls. Genetic testing reveals a mutation in the gene encoding dystrophin. Which of the following best explains the pathophysiology?

Accepted Answer

Defective dystrophin leads to excessive calcium influx, damaging contractile fibers and causing muscle degeneration.

Question 4

Which muscle is the prime mover for arm abduction at the shoulder joint?

Accepted Answer

Deltoid

Question 5

Which of the following muscles is responsible for initiating abduction of the arm and stabilizing the shoulder joint?

Accepted Answer

Supraspinatus

Question 6

A muscle fiber is unable to detach its myosin heads from actin after death due to lack of ATP. What is the resulting condition called?

Accepted Answer

Rigor mortis

Question 7

Which equation represents the direct phosphorylation of ADP by creatine phosphate during muscle contraction?

Accepted Answer

$$	ext{Creatine phosphate} + 	ext{ADP} ightarrow 	ext{Creatine} + 	ext{ATP}$$

Question 8

Which muscle group is the prime mover for extension of the thigh at the hip and flexion of the leg at the knee?

Accepted Answer

Hamstrings

Question 9

A patient is unable to dorsiflex their foot, resulting in 'foot drop.' Which muscle is most likely paralyzed?

Accepted Answer

Tibialis anterior

Question 10

Which of the following muscles is a synergist in elbow flexion and is best activated when the forearm is semipronated?

Accepted Answer

Brachioradialis

Question 11

Which muscle is the prime mover for plantar flexion of the foot when the leg is extended?

Accepted Answer

Gastrocnemius

Question 12

Which muscle is responsible for compressing the cheek and keeping food between teeth during chewing?

Accepted Answer

Buccinator

Question 13

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

Accepted Answer

Thin filaments slide past thick filaments, increasing overlap without changing filament length.

Question 14

Which muscle is the only quadriceps femoris member that crosses both the hip and knee joints, allowing it to flex the thigh and extend the leg?

Accepted Answer

Rectus femoris

Question 15

Which muscle is the prime mover for finger extension and also abducts (flares) the fingers?

Accepted Answer

Extensor digitorum

Question 16

A muscle contracts but does not shorten, and tension increases without movement. What type of contraction is this?

Accepted Answer

Isometric

Question 17

Which muscle is the prime mover for medial rotation of the arm at the shoulder joint?

Accepted Answer

Subscapularis

Question 18

Which muscle group is responsible for stabilizing the scapula during arm movements such as pushing or punching?

Accepted Answer

Serratus anterior

Question 19

Which muscle is the prime mover for dorsiflexion of the foot and also supports the medial arch?

Accepted Answer

Tibialis anterior

Question 20

Which muscle is responsible for flexing, abducting, and laterally rotating the thigh, and is the longest muscle in the body?

Accepted Answer

Sartorius

Muscular System: Structure, Function, and Major Muscles

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