what happens after muscle action potential?
- down special invaginations of sarcolemma
- reach sacroplasmic reticulum
- release calcium
what type of calcium channel is on the t-tubule sacrolemma?
L-type channel
what receptor is on the sacroplasmic reticulum calcium channel?
ryanodine receptor
what is the connection between calcium channel on t-tubule and Sacroplasmic reticulum?
electromechanical coupling
what is troponin T for?
binds tropomyosin
What is troponin C for?
calcium binding
what is troponin I for?
actin binding
how many heavy chain does myosin have?
1
how many light chain does myosin have?
2
what is on the heavy chain?
- rod
- hinge
- head
what is on the light chain?
- alkaline - stabilising head
- regulatory - regulates ATPase activity
what does desmin do?
scaffolds Z-line
what does titin do?
anchors myosin to Z-line
what does alpha-actinin do?
anchors actin to Z-line
what does myomesin do?
anchors tail of myosin to form m-line
what are the stages of muscle contraction?
- release calcium from SR
- calcium binds to troponin C
- conformational change
- troponin I release from actin
- troponin T moves tropomyosin from myosin
- myosin head free to interact with actin
describe cross bridge cycling
1) atp binds to myosin head
2) myosin dissociates from actin
3) ATP hydrolysed
4) myosin moves to cocked state
5) myosin binds to new place on actin
6) phosphate released
7) power stroke
8) sliding filaments
9) ADP released
