Exercise 12

Question 1

when a single muscle fiber contracts as. a result of a single stimulus (stimulus must be above threshold)

Answer 1

a twitch

Question 2

three components to a muscle fiber twitch

Answer 2

the latent period or lag phase, the contraction phase, and the relaxation phase

Question 3

latent period

Answer 3

time. btwn stimulation fo the muscle fiber and the development of force

Question 4

contraction phase

Answer 4

the time during which the muscle. fiber is developing force

Question 5

relaxation phase

Answer 5

the time. during which muscle fiber returns to its relaxed state

Question 6

skeletal muscles are innervated by

Answer 6

somatic motor neurons and the only response possible at a skeletal muscle NMJ is excitation

Question 7

A single somatic motor neuron can innervate ___

Answer 7

several muscle fibers

Question 8

each muscle fiber is innervated by

Answer 8

only one somatic motor neuron

Question 9

somatic motor unit

Answer 9

the somatic motor neuron and all the muscle fibers it innervates

Question 10

the number of muscle fibers innervated by a single somatic motor neuron determines

Answer 10

the size of the motor unit

Question 11

motor unit recruitment

Answer 11

occurs when the brain increases the number of motor units activated for a muscle contraction

Question 12

muscle fatigue

Answer 12

inability maintain maximal force; caused by depletion of ATP and accumulation of. muscle metabolic waste; a decrease in muscle force to 50% of the maximal force initially developed by. the muscle

Question 13

electromyography

Answer 13

measures the changes in skin voltage as a result of the electrical activity of. the skeletal muscles

Question 14

Skeletal muscles convert

Answer 14

chemical energy,, ATP, into mechanical energy