50.5 Nervous Control Of Muscle Tension

Question 1

how does the nervous system produce graded contractions of whole muscles?

Answer 1

1- varying number of muscle fibers that contract

2- varying rate at which muscle fibers are stimulates

Question 2

1 motor unit=

Answer 2

a single motor neuron and all the muscle fibers it controls

-action potential causes ALL to contract in a motor unit

Question 3

varying the number of muscle fibers that contract

Answer 3

-by selecting large vs small motor units to activate

Question 4

recruitment

Answer 4

the force/tension developed by muscle increases the more motor neurons are activated

Question 5

varying the rate of muscle fiber stimulation:

Answer 5

• when one AP comes before the first AP was finished, they add together to increase tension
• tetanus (when signals come so close, the muscle doesn’t relax at all between APs)

Question 6

tetanus

Answer 6

one smooth contraction caused by

• signals fusing
• high enough rate of muscle fiber stimulation that the muscle fiber can’t relax between signals