Explain the process of muscle contraction. Explain what happens at he motor endp
ID: 3483505 • Letter: E
Question
Explain the process of muscle contraction. Explain what happens at he motor endplate both on the nerve side and muscle side. How does the electrical impulse spread across the muscle and stimulate the contraction including the sliding filament model (where does it go, what is released, etc)?Thank you so very much :) Explain the process of muscle contraction. Explain what happens at he motor endplate both on the nerve side and muscle side. How does the electrical impulse spread across the muscle and stimulate the contraction including the sliding filament model (where does it go, what is released, etc)?
Thank you so very much :)
Thank you so very much :)
Explanation / Answer
1. When an electrical impulse come to axon terminal the voltage gated calcium channel opens.
2. From the calcium channels calcium ions diffuse from synaptic cleft to the axon terminal
3. Calcium causes fusion of synaptic vesicles and release of acetyl choline.
4. Acetyl choline is released to synaptic cleft by exocytosis
5. Once released it combines with nicotinic receptor on post synaptic membrane.
6. Acetylcholine receptor complex opens ligand gated sodium channels.
7. Due to sodium influx the resting membrane potential develops a minor change in potential called as end plate potential.
8. Once end plate potential reaches threshold level, an action potential is developed.
9. This action potential reaches the deep inside muscle through T tubules.
10. When an impulse reaches tip of T tubules, an voltage gated calcium channel is opened which is present on longitudinal sarcoplasmic tubules.
11. Calcium present in terminal cisterns is released to cytoplasm.
12. Thus calcium combines with troponin C and causes conformational change in actin filament.
13. This causes formation of actin and myosin cross Bridges.
14. An ATP Binds to myosin head and release energy.
15. Myosin head is energized and moves from 45 degree to 90 degree and attaches with actin and slides the actin filament.
16. In sarcomere unit actin filaments come closer and slides resulting in contraction of muscle.
17. So calcium is the link between excitation and contraction of muscle.
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