Skeletal Muscle: Structure, Function, and Innervation

Question 1

What is the specialized region where a motor neuron communicates with a muscle fiber?

Accepted Answer

Neuromuscular junction

Answer

Synapse

Answer

Myotendinous junction

Answer

Endomysium

Question 2

What is the primary role of the sarcoplasmic reticulum in skeletal muscle?

Accepted Answer

Calcium storage and release

Answer

Energy storage

Answer

Protein synthesis

Answer

Mitochondrial respiration

Question 3

What is the primary function of the Golgi tendon organ?

Accepted Answer

Sensing changes in muscle tension

Answer

Initiating muscle contraction

Answer

Controlling blood flow to the muscle

Answer

Transmitting sensory information to the brain

Question 4

Which sequence correctly describes the structural organization of skeletal muscle, starting with the smallest unit?

Accepted Answer

Muscle fibers → Fascicles → Entire muscle

Answer

Fascicles → Muscle fibers → Entire muscle

Answer

Entire muscle → Fascicles → Muscle fibers

Question 5

Identify the junction that transmits nerve impulses to muscle fibers.

Accepted Answer

Neuromuscular junction

Answer

Myotendinous junction

Answer

Synaptic cleft

Answer

Motor end plate

Question 6

Which muscle fiber type exhibits high glycolytic metabolism and fatigability?

Accepted Answer

Type IIb

Answer

Type I

Answer

Type IIa

Answer

Type IIx

Question 7

What is the primary function of the sarcoplasmic reticulum in skeletal muscle contraction?

Accepted Answer

Storage and release of calcium ions

Answer

Synthesis of muscle proteins

Answer

Generation of ATP

Answer

Transmission of nerve impulses

Question 8

Identify the neurotransmitter released at the neuromuscular junction.

Accepted Answer

Acetylcholine

Answer

Dopamine

Answer

Serotonin

Answer

Norepinephrine

Question 9

What is the primary role of satellite cells in skeletal muscle?

Accepted Answer

Muscle fiber regeneration

Answer

Muscle growth

Answer

Energy storage

Answer

Protein synthesis

Question 10

Skeletal muscle is characterized by all of the following EXCEPT:

Accepted Answer

Branched fibers

Answer

Voluntary control

Answer

Striated appearance

Answer

Multinucleated cells

Question 11

The specialized junction that facilitates communication between a motor neuron and a skeletal muscle fiber is known as the:

Accepted Answer

Neuromuscular junction

Answer

Myoneural junction

Answer

Synaptic cleft

Answer

Sarcomere

Question 12

Myosin is the protein component that forms the:

Accepted Answer

Thick filament

Answer

Thin filament

Answer

Z-disc

Answer

M-line

Question 13

Which type of muscle fiber is characterized by high endurance capacity and is suitable for prolonged activities?

Accepted Answer

Type I

Answer

Type IIa

Answer

Type IIb

Answer

Type IIx

Question 14

The process by which calcium ions initiate muscle contraction is known as:

Accepted Answer

Excitation-contraction coupling

Answer

Depolarization

Answer

Repolarization

Answer

Neurotransmission

Question 15

Which of the following is NOT a crucial function of the sarcoplasmic reticulum in muscle contraction?

Accepted Answer

Synthesizing muscle proteins

Answer

Storing calcium ions

Answer

Releasing calcium ions

Answer

Reuptake of calcium ions

Question 16

The cross-bridge that forms between actin and myosin during muscle contraction is referred to as the:

Accepted Answer

Myosin head

Answer

Z-disc

Answer

H-zone

Answer

Tropomyosin

Question 17

What type of muscle fiber has a high oxidative capacity and is suited for endurance activities?

Accepted Answer

Type I

Answer

Type IIa

Answer

Type IIx

Answer

Type IIb

Question 18

Which of the following conditions is characterized by progressive muscle weakness and wasting?

Accepted Answer

Muscular dystrophy

Answer

Myasthenia gravis

Answer

Botulism

Answer

Glaucoma

Question 19

Which type of skeletal muscle fiber is primarily responsible for endurance activities like long-distance running?

Accepted Answer

Slow oxidative fibers

Answer

Fast oxidative-glycolytic fibers

Answer

Intermediate fibers

Answer

Fast glycolytic fibers

Question 20

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

Accepted Answer

Acetylcholine

Answer

Norepinephrine

Answer

Dopamine

Answer

Glutamate

Question 21

Which of the following is NOT a component of a sarcomere?

Accepted Answer

Myelin sheath

Answer

Actin

Answer

Z-line

Answer

Myosin

Question 22

The sliding filament theory explains muscle contraction as the interaction between which two structures?

Accepted Answer

Actin and myosin filaments

Answer

Sarcomeres and myofibrils

Answer

T-tubules and sarcoplasmic reticulum

Question 23

What is the role of calcium ions during muscle contraction?

Accepted Answer

They bind to troponin, exposing the myosin-binding sites on actin.

Answer

They promote the release of acetylcholine from the motor neuron.

Answer

They directly activate the myosin ATPase.

Question 24

What is a TRUE statement about muscle fatigue?

Accepted Answer

Muscle fatigue is caused by a build-up of lactic acid and depletion of ATP.

Answer

Muscle fatigue is a psychological phenomenon with no physiological basis.

Answer

Muscle fatigue is primarily due to the depletion of calcium ions.

Question 25

What specialized structures within a muscle fiber facilitate rapid action potential propagation?

Accepted Answer

T-tubules

Answer

Myofibrils

Answer

Sarcomeres

Question 26

Which characteristic distinguishes skeletal muscle from smooth muscle?

Accepted Answer

Striated appearance

Answer

Involuntary control

Answer

Located in the walls of hollow organs

Answer

Single-unit structure

Question 27

What does a motor unit consist of?

Accepted Answer

A motor neuron and all the muscle fibers it innervates.

Answer

A group of motor neurons and the muscle fibers they innervate.

Answer

All the muscle fibers in a single muscle.