Question 1

Which of the following best describes the Sliding Filament Theory of muscle contraction?

Accepted Answer

Muscle contraction occurs when myosin heads bind to actin and pull the thin filaments toward the center of the sarcomere, causing the sarcomere to shorten.

Question 2

A cross-section of skeletal muscle reveals several structures. Which of the following correctly matches the structure to its description?

Accepted Answer

The epimysium surrounds the entire muscle.

Question 3

Which of the following is a correct sequence of events in the transmission of an action potential along a neuron?

Accepted Answer

Resting potential → Depolarization → Repolarization → Hyperpolarization

Question 4

A patient presents with muscle atrophy in the right leg after being immobilized in a cast for 6 weeks. Which of the following best explains the physiological basis for this atrophy?

Accepted Answer

Decreased stimulation leads to reduced protein synthesis and increased protein degradation in muscle fibers.

Question 5

Which of the following best distinguishes between the central nervous system (CNS) and the peripheral nervous system (PNS)?

Accepted Answer

The CNS consists of the brain and spinal cord, while the PNS includes all neural tissue outside the CNS.

Question 6

Which of the following is a characteristic of fast-twitch (Type II) muscle fibers?

Accepted Answer

They contract quickly and generate more force but fatigue rapidly.

Question 7

During muscle contraction, which ion is released from the sarcoplasmic reticulum and is essential for the interaction between actin and myosin?

Accepted Answer

Calcium ($Ca^{2+}$)

Question 8

A muscle is observed to have many mitochondria, a rich blood supply, and contracts slowly but resists fatigue. Which muscle fiber type is this most likely to be?

Accepted Answer

Type I (slow oxidative)

Question 9

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

Accepted Answer

It is the site where a motor neuron communicates with a muscle fiber to initiate contraction.

Question 10

A person is able to flex their elbow by contracting the biceps brachii. Which of the following best describes the role of the biceps brachii in this movement?

Accepted Answer

It acts as the agonist (prime mover).

Question 11

Which of the following best describes the difference between hypertrophy and hyperplasia in muscle tissue?

Accepted Answer

Hypertrophy is an increase in the size of existing muscle fibers, while hyperplasia is an increase in the number of muscle fibers.

Question 12

Which of the following best describes the function of a motor unit?

Accepted Answer

A motor unit consists of a single motor neuron and all the muscle fibers it innervates.

Question 13

Which of the following best explains why muscle strength generally decreases with age?

Accepted Answer

There is a decrease in muscle mass and a reduction in the number and size of muscle fibers.

Question 14

Which of the following best describes the difference between afferent and efferent neurons?

Accepted Answer

Afferent neurons carry sensory information to the CNS, while efferent neurons carry motor commands from the CNS to effectors.

Question 15

A patient has damage to the myelin sheath of their peripheral nerves. Which of the following is the most likely consequence?

Accepted Answer

Decreased speed of nerve impulse conduction due to impaired saltatory conduction.

Question 16

Which of the following equations correctly represents the Nernst equation for calculating the equilibrium potential ($E_{ion}$) for a given ion?

Accepted Answer

$E_{ion} = \frac{RT}{zF} \ln \left( \frac{[ion]_{outside}}{[ion]_{inside}} \right)$

Question 17

Which of the following best describes the role of acetylcholine at the neuromuscular junction?

Accepted Answer

It binds to receptors on the muscle fiber membrane, leading to depolarization and initiation of an action potential.

Question 18

A person is unable to dorsiflex their foot after an injury. Which muscle is most likely affected?

Accepted Answer

Tibialis anterior

Question 19

Which of the following best describes the difference between the somatic and autonomic divisions of the nervous system?

Accepted Answer

The somatic division controls voluntary movements of skeletal muscles, while the autonomic division regulates involuntary functions such as heart rate and digestion.

Question 20

A muscle is described as having its origin on the scapula and its insertion on the radius. Which of the following best describes the movement produced by this muscle?

Accepted Answer

Flexion of the forearm at the elbow

Muscle Anatomy, Physiology, and Nervous System Study Guide

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