The Muscular System: Key Terms

Question 1

actin

Answer 1

one of the two contractile proteins in muscle cells; the other is myosin

Question 2

agonist

Answer 2

the muscle that carries out a given movement; prime mover

Question 3

antagonist

Answer 3

the muscle that opposes an agonist; it must relax when the agonist contracts

Question 4

cardiac muscle

Answer 4

involuntary muscle that makes up the heart wall

Question 5

fascia

Answer 5

the fibrous sheath of connective tissue that covers a muscle; called deep fascia to differentiate it from the superficial fascia that underlies the skin

Question 6

fascicle

Answer 6

a small bundle, as of muscle or nerve fibers

Question 7

insertion

Answer 7

in a given movement, the point where a muscle attaches to a moving part of the skeleton

Question 8

muscle

Answer 8

and organ that produces movement by contracting; also the tissue that composes such organs

Question 9

myosin

Answer 9

one of the two contractile proteins in muscle cells; the other is actin

Question 10

neuromuscular junction (NMJ)

Answer 10

the point of contact, or synapse, between a branch of a motor neuron and a muscle cell

Question 11

origin

Answer 11

in a given movement, the point where a muscle is attached to a stable part of the skeleton

Question 12

skeletal muscle

Answer 12

voluntary muscle that moves the skeleton and maintains posture

Question 13

smooth muscle

Answer 13

involuntary muscle that makes of the wall of hollow organs, vessels, and ducts; visceral muscle

Question 14

synergist

Answer 14

a muscle that assists an agonist to produce a given movement

Question 15

tendon

Answer 15

a fibrous band of connective tissue that attaches a muscle to a bone

Question 16

tonus

Answer 16

a state of steady, partial muscle contraction that maintains firmness; muscle tone

Question 17

acetylcholine (ACh)

Answer 17

a neurotransmitter that stimulates contraction of skeletal muscles