Q: Which equation best represents the action of the sodium-potassium pump in muscle fibers?

$$\text{3 Na}^+ \text{(out)} + 2 K^+ \text{(in)} + \text{ATP} \rightarrow \text{ADP} + \text{P}$$

Q: Which equation represents the net ATP yield from glycolytic (anaerobic) catabolism of one glucose molecule?

$$\text{Glucose} \rightarrow 2 \text{Pyruvate} + 2 \text{ATP}$$

Question 1

Which property of muscle cells allows them to return to their original length after being stretched?

Accepted Answer

Elasticity

Question 2

A patient with Duchenne Muscular Dystrophy (DMD) is experiencing progressive muscle weakness. Which protein is defective in this disease, and what is its primary function?

Accepted Answer

Dystrophin; anchors the sarcolemma to the endomysium and myofibrils

Question 3

During the sliding-filament mechanism of contraction, which of the following statements is TRUE?

Accepted Answer

Thin filaments slide toward the M line, causing the sarcomere to shorten

Question 4

Which equation best represents the action of the sodium-potassium pump in muscle fibers?

Accepted Answer

$$	ext{3 Na}^+ 	ext{(out)} + 2 K^+ 	ext{(in)} + 	ext{ATP} ightarrow 	ext{ADP} + 	ext{P}$$

Question 5

A muscle fiber is stimulated repeatedly at a frequency of 90 times per second. Which type of contraction is most likely to occur?

Accepted Answer

Fused (complete) tetanus

Question 6

Which of the following best describes the role of acetylcholinesterase (AChE) at the neuromuscular junction?

Accepted Answer

It degrades acetylcholine, terminating the signal for muscle contraction

Question 7

Which process provides the most ATP for sustained muscle activity lasting several minutes?

Accepted Answer

Oxidative (aerobic) catabolism

Question 8

A muscle fiber is at its optimal length before contraction. What is the expected outcome regarding tension production?

Accepted Answer

Maximum tension due to optimal overlap of thick and thin filaments

Question 9

Which of the following is TRUE regarding the crossbridge cycle in skeletal muscle contraction?

Accepted Answer

ATP hydrolysis 'cocks' the myosin head into its high-energy position

Question 10

Which type of muscle tissue is found lining hollow organs and is responsible for peristalsis?

Accepted Answer

Smooth muscle

Question 11

A patient receives an injection of botulinum toxin (Botox®) for cosmetic purposes. What is the mechanism by which this toxin affects muscle contraction?

Accepted Answer

It blocks the release of acetylcholine from motor neurons

Question 12

Which equation represents the net ATP yield from glycolytic (anaerobic) catabolism of one glucose molecule?

Accepted Answer

$$	ext{Glucose} ightarrow 2 	ext{Pyruvate} + 2 	ext{ATP}$$

Question 13

Which of the following is a real-world example of an isotonic eccentric contraction?

Accepted Answer

Slowly lowering a weight to the ground

Question 14

Which protein is responsible for the elasticity of muscle fibers, allowing them to 'spring' back after being stretched?

Accepted Answer

Titin

Question 15

Which of the following best describes the function of myoglobin in muscle fibers?

Accepted Answer

Binds oxygen for oxidative catabolism

Question 16

A muscle fiber is unable to relax and remains in a spasm. Which of the following could be a cause?

Accepted Answer

Dehydration and electrolyte imbalances

Question 17

Which type of muscle fiber is best suited for endurance activities such as distance running?

Accepted Answer

Type I (Slow Oxidative) fibers

Question 18

Which of the following is TRUE regarding the refractory period in a muscle twitch?

Accepted Answer

It is the interval when the muscle fiber cannot respond to another stimulus

Question 19

Which of the following best explains why rigor mortis occurs after death?

Accepted Answer

ATP is depleted, preventing myosin heads from detaching from actin

Question 20

Which of the following is a function of muscle tone in the body?

Accepted Answer

Maintains posture and stabilizes joints

Muscle Tissue and Physiology: Structured Study Notes for Anatomy & Physiology

Study Guide - Practice Questions

Study Guide - Flashcards