Deck 20: Skeletal Muscle Structure and Function

Question 1

A muscle can serve as an agonist in one action and an antagonist in another action.

Answer 1

True

Question 2

Which region of a sarcomere contains thick filaments overlapping with thin filaments?

A) A band
B) Z line
C) H zone
D) I band
E) M line

Answer 2

A

Question 3

What is the role of tropomyosin in a sarcomere?

A) It is the main protein component of thin myofilaments.
B) It blocks the active sites on actin filaments in relaxed muscle fibers.
C) It is the main component of elastic filaments.
D) It is the main protein component in thick myofilaments.
E) It binds to calcium to initiate muscle contraction.

Answer 3

B

Question 4

Which of the following is NOT true of a myofibril?

A) Thin myofilaments consist of actin, troponin, and tropomyosin.
B) Elastic filaments are composed of titin.
C) Thick myofilaments consist of myosin.
D) Myofibrils are composed of muscle fibers.
E) All of these are true of myofibrils.

Question 5

Which of the following is NOT a method of naming muscles?

A) By the relative size of the muscle
B) By the action of the muscle
C) By the number of origins that the muscle has
D) By the shape of the muscle
E) All of these are methods of naming muscles.

Question 6

A skeletal muscle is considered to be an organ of the muscular system.

Question 7

Which of the following does NOT occur as a sarcomere shortens during muscle contraction?

A) The thin and thick myofilaments shorten in length.
B) The I bands shorten.
C) The Z lines (discs) move closer together.
D) The H zone shortens.
E) All of these occur as a sarcomere shortens.

Question 8

The synaptic knob of a neuromuscular junction is the portion of the muscle fiber that contains receptor sites for neurotransmitters.

Question 9

What is a fascicle of a skeletal muscle?

A) A layer of connective tissue surrounding an entire skeletal muscle
B) A contractile unit of a myofibril
C) An inward extension of the sarcolemma through the muscle fiber
D) A bundle of skeletal muscle fibers
E) A motor neuron and all of the muscle fibers that it innervates

Question 10

Whenever an object is lifted, all motor units in the appropriate muscle(s) are stimulated, regardless of the weight of the object.

Question 11

Which of the following organelles stores calcium in skeletal muscle fibers for contraction?

A) Mitochondria
B) Transverse tubules
C) Sarcolemma
D) Sarcoplasm
E) Sarcoplasmic reticulum

Question 12

The origin of a skeletal muscle is the attachment site at the less moveable/more stationary end.

Question 13

A muscle fiber is identical to a muscle cell.

Question 14

A sheet of connective tissue, which connects muscles (or parts of muscles) to other muscles (or their parts), is called a(n)

A) tendon.
B) aponeurosis.
C) fascia.
D) fascicle.
E) sarcolemma.

Question 15

A muscle that contracts to assist the main muscle in performing a particular action is called a(n)

A) prime mover.
B) fixator.
C) antagonist.
D) agonist.
E) synergist.

Question 16

In a motor unit, each neuron innervates (controls) a single muscle fiber.

Question 17

What does "striated" mean, as it applies to skeletal muscle?

A) It means that skeletal muscle action can be willed to occur.
B) It means that skeletal muscle appears striped, due to alternating Z and M lines in each sarcomere.
C) It means that the tissue appears striped, due to the pattern formed by multinucleated cells.
D) It means that skeletal muscle tissue consists of motor units.
E) It means that the tissue appears striped, due to the repeating pattern of the A bands and I bands in the sarcomeres.

Question 18

The boundary between adjacent sarcomeres is the

A) A band
B) H zone
C) Z line (disc)
D) I band
E) M line

Question 19

A particular muscle causes flexion of the lower limb at the knee. It is located on the posterior side of the thigh. Where would you expect to find its antagonist?

A) On the medial side of the thigh
B) On the anterior side of the thigh
C) On the lateral side of the thigh
D) On the posterior side of the thigh too
E) On any side of the thigh

Question 20

The connective tissue layer that surrounds each bundle of muscle fibers is called the

A) endomysium.
B) fascicle.
C) perimysium.
D) fascia.
E) epimysium.