exam

Question 1

What is a motor unit?

Answer 1

A motor unit consist of a neuron and the muscle fibers it innervates

Question 2

Subthreshold

Answer 2

Not strong enough to cause an action potential or in a muscle contraction

Question 3

Threshold

Answer 3

is strong enough to produce an action potential/muscle contraction in a single motor unit

Question 4

Submaximal

Answer 4

Strong enough to produce action potential in 4 motor units

Question 5

Maximal

Answer 5

strong enough to produce action potential in ALL motor units of a particular muscle

Question 6

what are muscle spindles and what do they do?

Answer 6

• Are primarily in the muscle belly between the fibers and sensitive to stretch and rate of stretch
• when a rapid muscle stretch occurs, the muscles spindles detect and sends signals to the CNS, CNS activates motor neurons of the muscle and causes it to contract and to activate causing it to stretch

Question 7

What is G T O & what do they do?

Answer 7

• found in tendon close to the muscle tendon junction, sensitive to both muscle tension & active contraction and less sensitive to stretch that requires a greater stretch to be activated
• tension in tendons and G T O increases as the muscle contracts, which activates G T O, G T O stretch is reached where it is sent to the CNS that causes the muscle to relax, G T O protects us from excessive contraction by causing its muscle to relax

Question 8

Sliding Filament Theory

Answer 8

sacromere contracts, active filaments at each end will slide inward on myosin filaments, pulling the Z-lines toward the center of the sacromere & shortening the muscle fiber