Question 1

Which of the following best describes the role of calcium ions ($$\mathrm{Ca$$^{2+}$$}) in $$skeletal muscle contraction?

Accepted Answer

Calcium ions bind to troponin, causing tropomyosin to move and expose myosin-binding sites on actin.

Question 2

During the excitation-contraction coupling process, which event directly follows the release of acetylcholine at the neuromuscular junction?

Accepted Answer

An action potential is generated along the sarcolemma.

Question 3

A patient is experiencing muscle weakness due to a defect in the acetylcholine receptor at the neuromuscular junction. Which process is most directly impaired?

Accepted Answer

Generation of an action potential in the muscle fiber

Question 4

Which equation correctly represents the hydrolysis of ATP during muscle contraction?

Accepted Answer

$$\mathrm{ATP + H_2O \rightarrow ADP + P_i + Energy}$$

Question 5

Which of the following best explains the difference between isotonic and isometric muscle contractions?

Accepted Answer

Isotonic contractions involve a change in muscle length while tension remains constant; isometric contractions involve tension without a change in muscle length.

Question 6

Which of the following muscle fiber types is most resistant to fatigue and best suited for endurance activities?

Accepted Answer

Slow oxidative fibers

Question 7

A sprinter relies primarily on which muscle fiber type during a 100-meter dash?

Accepted Answer

Fast glycolytic fibers

Question 8

Which of the following best describes the 'sliding filament model' of muscle contraction?

Accepted Answer

Actin and myosin filaments slide past each other, shortening the sarcomere and producing contraction.

Question 9

Which of the following events occurs first during the process of muscle contraction?

Accepted Answer

Binding of acetylcholine to receptors on the motor end plate

Question 10

A muscle twitch consists of which three phases, in order?

Accepted Answer

Latent period, contraction phase, relaxation phase

Question 11

Which of the following best explains temporal summation in muscle physiology?

Accepted Answer

Increasing the frequency of stimulation so that contractions build upon each other

Question 12

Which of the following is the correct sequence of events for excitation-contraction coupling in skeletal muscle?

Accepted Answer

Action potential travels along sarcolemma → calcium released from sarcoplasmic reticulum → troponin binds calcium → tropomyosin moves → myosin binds actin

Question 13

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

Accepted Answer

It transmits the action potential from the motor neuron to the muscle fiber.

Question 14

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

Accepted Answer

Acetylcholine

Question 15

Which of the following is a direct result of ATP binding to the myosin head during muscle contraction?

Accepted Answer

The myosin head detaches from actin.

Question 16

A muscle fiber adapts to increased exercise by which of the following mechanisms?

Accepted Answer

Increasing the number of myofibrils and mitochondria

Question 17

Which of the following best explains why fast glycolytic fibers fatigue more quickly than slow oxidative fibers?

Accepted Answer

Fast glycolytic fibers have fewer mitochondria and rely on anaerobic metabolism.

Question 18

Which of the following is true regarding the propagation of an action potential along the sarcolemma?

Accepted Answer

It involves the influx of sodium ions ($$\mathrm{Na^+}) $$through voltage-gated channels.

Question 19

Which of the following best describes the structure of a sarcomere?

Accepted Answer

It is the region between two Z discs and contains overlapping actin and myosin filaments.

Muscle Tissue Structure and Function: Study Notes for Anatomy & Physiology

Guida di studio - Domande di pratica

Study guide - Flashcard