Muscle Contraction and Relaxation: Learn the Mechanisms of Muscle Movement

Question 1

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

Accepted Answer

Acetylcholine

Answer

Dopamine

Answer

Epinephrine

Answer

Serotonin

Question 2

What is the primary energy source for muscle cells during contraction?

Accepted Answer

ATP

Answer

ADP

Answer

Glucose

Answer

Creatine phosphate

Question 3

During the relaxation phase of muscle contraction, what event occurs?

Accepted Answer

Calcium ions are released from the sarcoplasmic reticulum.

Answer

Calcium ions bind to troponin.

Answer

Tropomyosin moves to expose myosin-binding sites.

Answer

Myosin heads bind to actin.

Question 4

Which type of muscle contraction occurs when the muscle shortens while generating force?

Accepted Answer

Concentric contraction

Answer

Eccentric contraction

Answer

Isometric contraction

Answer

Isokinetic contraction

Question 5

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

Accepted Answer

To store and release calcium ions

Answer

To produce ATP

Answer

To regulate muscle relaxation

Answer

To transmit action potentials

Question 6

Which component is NOT involved in the sliding filament theory of muscle contraction?

Accepted Answer

Mitochondria

Answer

Thick filaments

Answer

Thin filaments

Answer

Motor proteins

Question 7

What is the main function of ATP hydrolysis during muscle contraction?

Accepted Answer

To provide energy for the power stroke

Answer

To release calcium ions from the sarcoplasmic reticulum

Answer

To bind myosin heads to actin

Answer

To initiate the relaxation phase

Question 8

What process marks the initial stage of muscle tissue repair after an injury?

Accepted Answer

Phagocytosis

Answer

Neovascularization

Answer

Myoblast fusion

Question 9

Which muscle fiber type is most suitable for endurance activities, such as long-distance running?

Accepted Answer

Type I

Answer

Type IIa

Answer

Type IIx

Question 10

Which neurotransmitter initiates muscle contraction by binding to receptors on the muscle membrane?

Accepted Answer

Acetylcholine

Answer

Dopamine

Answer

Serotonin

Answer

Norepinephrine

Question 11

Which of the following is NOT a role of ATP in muscle contraction?

Accepted Answer

Releases calcium ions from the sarcoplasmic reticulum

Answer

Provides energy for myosin head movement

Answer

Hydrolyses to ADP and inorganic phosphate

Answer

Binds to tropomyosin to initiate contraction

Question 12

Describe the sliding filament theory of muscle contraction.

Accepted Answer

During contraction, myosin and actin filaments slide past each other to shorten the muscle.

Answer

During contraction, myosin and actin filaments expand to lengthen the muscle.

Answer

During contraction, calcium ions slide along microtubules to trigger muscle shortening.

Answer

During contraction, neurotransmitters stimulate actin filaments to slide past myosin filaments.

Question 13

What is the refractory period of a muscle fibre?

Accepted Answer

The period during which a muscle fibre is incapable of responding to a stimulus

Answer

The period during which a muscle fibre is most sensitive to a stimulus

Answer

The period during which a muscle fibre is contracting

Answer

The period during which a muscle fibre is relaxing

Question 14

In muscle contraction, how do calcium ions trigger the sliding of myofilaments?

Accepted Answer

Calcium ions bind to troponin, causing a shape change that reveals myosin binding sites on actin.

Answer

Calcium ions bind to actin, causing it to slide towards the center of the sarcomere.

Answer

Calcium ions bind to myosin, causing a shape change that exposes its binding sites for actin.

Question 15

Which neurotransmitter stimulates muscle fibres to contract?

Accepted Answer

Acetylcholine

Answer

Dopamine

Answer

Epinephrine

Answer

Serotonin

Question 16

Which of these is not a type of muscle contraction?

Accepted Answer

Anisotonic

Answer

Isotonic

Answer

Isometric

Answer

Plyometric

Question 17

What is the role of the sliding filament theory in muscle contraction?

Accepted Answer

Explains the movement of actin and myosin filaments past each other

Answer

Describes how calcium ions trigger muscle contraction

Answer

Demonstrates the role of ATP in muscle relaxation

Answer

Explains the function of the sarcoplasmic reticulum

Question 18

Which of these muscles primarily flexes the elbow joint?

Accepted Answer

Biceps brachii

Answer

Triceps brachii

Answer

Deltoid

Answer

Lattisimus dorsi

Question 19

What type of muscle fibre has high oxidative capacity and slow contraction speed?

Accepted Answer

Type I

Answer

Type IIa

Answer

Type IIx

Answer

Type IIc

Question 20

Which neurotransmitter is released at the neuromuscular junction, triggering muscle contraction?

Accepted Answer

Acetylcholine

Answer

Dopamine

Answer

Serotonin

Answer

Norepinephrine

Question 21

What is the primary energy source for muscle contraction?

Accepted Answer

ATP

Answer

UDP

Answer

ADP

Answer

GTP

Question 22

Who proposed the sliding filament theory of muscle contraction?

Accepted Answer

Hugh Huxley and Andrew Huxley

Answer

George Palade and Albert Claude

Answer

Francis Crick and James Watson

Answer

Jonas Salk and Albert Sabin

Question 23

Which ion causes the depolarization phase of a muscle action potential?

Accepted Answer

Sodium

Answer

Calcium

Answer

Chloride

Answer

Potassium

Question 24

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

Accepted Answer

Stores and releases calcium ions

Answer

Contains the myofilaments

Answer

Produces ATP

Answer

Conducts electrical impulses

Question 25

What process restores a muscle to its resting state after contraction?

Accepted Answer

Repolarization

Answer

Hyperpolarization

Answer

Polarization

Answer

Depolarization

Question 26

Which of the following contributes to muscle fatigue?

Accepted Answer

Depletion of ATP and glycogen

Answer

Increased oxygen supply

Answer

Increased blood flow

Answer

Enhanced ion channel activity

Question 27

What is the role of proprioceptors in muscle control?

Accepted Answer

Provide feedback on muscle length and tension

Answer

Conduct electrical impulses

Answer

Store calcium ions

Answer

Initiate muscle action potentials