Question 1

Which muscle is primarily responsible for hip extension during activities such as climbing stairs?

Accepted Answer

Gluteus maximus

Question 2

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

Accepted Answer

Tibialis anterior

Question 3

During a soccer kick, which muscle group is primarily responsible for knee extension?

Accepted Answer

Quadriceps

Question 4

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

Accepted Answer

It stores and releases calcium ions ($$Ca^{2+}) $$necessary for contraction.

Question 5

The neuromuscular junction is the site where:

Accepted Answer

A motor neuron communicates with a muscle fiber.

Question 6

Which of the following correctly matches a muscle with its primary action at the hip joint?

Accepted Answer

Iliopsoas: flexion

Question 7

A runner experiences difficulty with plantarflexion after an Achilles tendon injury. Which muscle is most likely affected?

Accepted Answer

Gastrocnemius

Question 8

Which of the following statements about muscle contraction is correct?

Accepted Answer

Muscle fibers contract (shorten) when activated.

Question 9

Which structure transmits the action potential from the sarcolemma into the interior of the muscle fiber?

Accepted Answer

Transverse (T) tubules

Question 10

A patient presents with weakness in hip abduction. Which muscle is most likely involved?

Accepted Answer

Gluteus medius

Question 11

Which of the following best describes the function of the sodium-potassium pump in muscle cells?

Accepted Answer

It maintains the resting membrane potential by moving $$3\ Na^+$$ out and $$2\ K^+ in.$$

Question 12

Which of the following is the correct sequence of events during skeletal muscle contraction?

Accepted Answer

Action potential → $$Ca^{2+}$$ release → Cross-bridge formation → Power stroke

Question 13

Which muscle group is primarily responsible for knee flexion?

Accepted Answer

Hamstrings

Question 14

Which of the following best describes the sliding-filament mechanism?

Accepted Answer

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

Question 15

A patient is unable to adduct their thigh. Which muscle group is most likely affected?

Accepted Answer

Adductor group

Question 16

Which of the following is true regarding the difference between skeletal, cardiac, and smooth muscle?

Accepted Answer

Skeletal muscle is under voluntary control, while cardiac and smooth muscle are involuntary.

Question 17

Which of the following best describes the function of ligand-gated channels at the neuromuscular junction?

Accepted Answer

They open in response to acetylcholine binding, allowing $$Na^+ to $$enter the muscle cell.

Question 18

A person is unable to stand on their toes. Which muscle is most likely weak or damaged?

Accepted Answer

Soleus

Question 19

Which of the following structures is composed of repeating units called sarcomeres?

Accepted Answer

Myofibril

Question 20

A patient with a genetic defect in their actin protein would most likely have problems with which aspect of muscle function?

Accepted Answer

Forming thin filaments necessary for contraction

Muscle Groups, Actions, and Muscle Tissue Physiology: Study Notes for Anatomy & Physiology

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