connective tissues + how muscles contract

Question 1

fascia

Answer 1

separates muscle

Question 2

epimysium

Answer 2

closely surrounds entire muscle

Question 3

perimysium

Answer 3

covers a bundle of muscle fibers

Question 4

endomysium

Answer 4

covers individual muscle fibers

Question 5

actin

Answer 5

thin protein filaments

Question 6

myosine

Answer 6

thick protein filaments

Question 7

sequence of events for a muscle contraction (10 steps)

Answer 7

1. electrical impulse sent down the motor neuron
2. acetylcholine (Ach) released into neuromuscular junction
3. Ca2+ released from T tubules of sarcoplasmic reticulum
4. Ca2+ binds to troponin, leads to shift of tropomyosin
5. exposes binding sites of actin causes myosin heads to bind with actin (cross-bridge formation)
6. myosin ATPase splits ATP to provide energy for movement of cross-bridge (power stroke)
7. ATP binds with myosin to dissociate cross-bridge
8. combining, detaching, and recombining continues as long as nerve impulse and ATP is present
   9 when muscle non longer stimulated, Ca2+ decreases, allows actin and myosin to dissociate