Steps in Muscle Contraction

Question 1

1st Step in Muscle Contraction

Answer 1

Nerve sends action impulse and reaches axon terminals

Question 2

2nd Step in Muscle Contraction

Answer 2

Acetylcholine diffuses across neuromuscular junction to receptors on sarcolemma

Question 3

3rd step in Muscle Contraction

Answer 3

sarcoplasmic reticulum releases calcium ions

Question 4

4th step in Muscle Contraction

Answer 4

calcium binds to troponin on actin filament triggering tropomyosin to expose binding sites

Question 5

5th step in Muscle Contraction

Answer 5

-If ADP and P are available, cross bridges form between actin and myosin
-actin fibrils in A band slide toward the H zone in the center
-this is a contraction

Question 6

6th step in Muscle Contraction

Answer 6

ATP attached to myosin head causes cross bridge break
-muscle fiber relaxes

Question 7

7th step in Muscle Contraction

Answer 7

calcium ions are reabsorbed in sarcoplasmic reticulum