steps of contraction

1

Ach is released by neuron

2

Ach crosses synaptic cleft and binds to Na+ channels on the sarcolemma

3

Na+ (sodium) channels open up voltage changes create action potential

4

Electric impulses (action potential) travels across membrane and down T-tubles into cell

5

sarcoplasmic reticulum near T-tubles releases Ca2+

6

Calcium binds to protein troponin and changes shape to open binding site from myosin -trafomyosin get out!

7

Myosin cross bridges (beads) attach to action

8

Power stroke: myosin head pivot to pull actin using Atp and cause sarcomere to shorten

9

Myosin contnues to pivot with addition and use of ATP

10

Signals end, calcium levels drop again because calcium is absorbed by sarcoplasmic reticulum

11

Myosin releases actin and muscle relaxes