week 3: 10.4 excitation contraction coupling

Question 1

1. neural control

Answer 1

skeletal muscle fiber contacts when stimulated by a motor neuron at NMJ
stimulus arrives in form of action potential at axon terminal

Question 2

2. excitation

Answer 2

action potential causes the release of ACh into synpatic cleft, leads to excitation- production of action potential in sarcolemma

Question 3

3. release of calcium ions

Answer 3

action potential travels along sarcolemma and down T tubules to the triads
triggers the release of calcium ions from terminal cisternae of sarcoplasmic reticulum

Question 4

4. contraction cycle begins

Answer 4

contraction cycle begins when calcium ions bind to troponin resulting in exposure of active sights on thin filaments,
allows cross-bridge formation and will continue as long as ATP is available

Question 5

5. sarcomere shortening

Answer 5

as the thick and thin filaments interact, sarcomeres shorten, pulling the ends of the muscle fiber closer together

Question 6

6. generation of muscle tension

Answer 6

during contraction, entire skeletal muscle shortens and produces a pull/ tension on the tendons at either end