Question 1

Which of the following best describes the role of the sarcoplasmic reticulum (SR) in muscle contraction?

Accepted Answer

It stores and releases calcium ions ($$Ca^{2+}$$), which are essential for initiating muscle contraction.

Question 2

During the sliding filament mechanism, which event directly leads to muscle contraction?

Accepted Answer

Myosin heads bind to actin filaments, forming cross-bridges.

Question 3

What is the correct sequence of events for an action potential in a neuron?

Accepted Answer

Depolarization, repolarization, resting potential reestablishment

Question 4

Which muscle group is primarily responsible for flexing the trunk and allowing movement of abdominal organs?

Accepted Answer

Core Muscles: Abdominals

Question 5

A nerve impulse travels down a motor neuron and reaches the neuromuscular junction. What is the next step in the process of muscle contraction?

Accepted Answer

Release of acetylcholine into the synaptic cleft

Question 6

Which of the following best explains why muscle contraction produces heat in the human body?

Accepted Answer

Muscle contraction is a byproduct of metabolic activity, which releases heat as energy is used to produce movement.

Question 7

Which structure in a muscle cell is responsible for transmitting the electrical impulse deep into the muscle fiber?

Accepted Answer

T Tubules

Question 8

What is the primary function of graded potentials in neurons?

Accepted Answer

They are short-lived changes in membrane potential that can trigger an action potential if the threshold is reached.

Question 9

Which of the following events occurs during the relaxation phase of muscle contraction?

Accepted Answer

Calcium ions are pumped back into the sarcoplasmic reticulum, requiring ATP.

Question 10

Isotonic contractions differ from isometric contractions in which of the following ways?

Accepted Answer

Isotonic contractions involve muscle shortening and movement, while isometric contractions maintain constant muscle length.

Question 11

Which of the following best describes the function of the diaphragm muscle?

Accepted Answer

It separates the thoracic cavity from the abdominal cavity and is essential for breathing.

Question 12

What is the role of ATP in the contraction and relaxation of muscle fibers?

Accepted Answer

ATP is required for both the detachment of myosin heads from actin and for pumping calcium ions back into the sarcoplasmic reticulum.

Question 13

Which event marks the beginning of the contraction phase in the muscle contraction cycle?

Accepted Answer

Myosin heads pull the actin filaments toward the center of the sarcomere.

Question 14

Which of the following is a correct description of the function of intercostal muscles?

Accepted Answer

They assist in expanding and contracting the chest cavity during breathing.

Question 15

A patient is unable to move their toes upward (dorsiflexion). Which muscle group is most likely affected?

Accepted Answer

Lower Body Muscles: Calves

Question 16

Which of the following best explains the importance of the threshold potential in neurons?

Accepted Answer

It is the membrane voltage that must be reached to trigger an action potential.

Question 17

Which process is responsible for restoring the resting membrane potential after an action potential?

Accepted Answer

The sodium-potassium pump ($$Na^+/K^+$$ ATPase) helps return the neuron to its resting potential.

Question 18

Which of the following is a function of the pectoral muscles?

Accepted Answer

They allow for arm rotation and lifting.

Question 19

Which of the following best describes the role of acetylcholine in muscle contraction?

Accepted Answer

It is a neurotransmitter released at the neuromuscular junction, initiating muscle contraction.

Question 20

Which phase of muscle contraction is characterized by the transport of calcium ions back into the sarcoplasmic reticulum?

Accepted Answer

Relaxation Phase

BIOS110 Exam 2 Review Guide

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