Lesson 5.2

Question 1

acetycholine

Answer 1

a neurotransmitter chemical that stimulates muscle.

Question 2

action potential

Answer 2

the electric charge produced in nerve or muscle fiber by stimulation.

Question 3

all-or-none law

Answer 3

the rule stating that the fibers in a given motor unit always develop maximum tension when stimulated.

Question 4

axon

Answer 4

a long, thin fiber connected to the motor neuron cell body.

Question 5

axon terminals

Answer 5

offshoots of the axon that branch out to connect with individual muscle fibers.

Question 6

cross bridges

Answer 6

connections between the heads of myosin filaments and receptor sites on the actin filaments.

Question 7

fast-twitch

Answer 7

type of muscle that contracts quickly.

Question 8

motor neuron

Answer 8

a nerve that stimulates skeletal muscle tissue.

Question 9

motor unit

Answer 9

a single motor neuron and all of the muscle fibers that it stimulates.

Question 10

neuromuscular junction

Answer 10

the link between an axon terminal and a muscle fiber.

Question 11

parallel

Answer 11

a type of muscle fiber arrangement in which fiber attaches obliquely to the central tendon.

Question 12

sarcomeres

Answer 12

units composed of actin that contract slowly and is fatigue resistant.

Question 13

slow-twitch

Answer 13

type of muscle that contracts slowly and is fatigue resistant.