Muscle Contraction

Question 1

mechanism of muscle contraction structure of skeletal muscles

Answer 1

✓ muscle
✓ muscle fascicle
✓ muscle fiber
✓ myofibrils

Question 2

myofibrils contractile elements, what element?

Answer 2

actin and myosin

Question 3

Muscle fiber

Answer 3

1. Sarcolemma
2. Sarcoplasm
3. Myofibrils

Question 4

Actin Filaments

Answer 4

a. F actin strands
b. tropomyosin
c. troponin (T, I, C)

Question 5

during contraction

Answer 5

✓ I- band disappear
✓ H- band disappear
✓ M- band disappear
✓ the length of sarcomere decreases

Question 6

Mechanism of Muscle Contraction (Steps)

Answer 6

✓ Step 1. nerve impulses travel toward the synaptic knob
✓ Step 2. Ca ++ ion from the ECF inter into the synaptic knob through the calcium channel
✓ Step 3. As Ca ++ enters the synaptic knob, acetylcholine vesicles rupture and is released out into the synaptic cleft by exocytosis
✓ Step 4. Ach diffuses across the neuromuscular junctions and binds to the receptor sites on the postsynaptic membrane.
✓ Step 5. Stimulating the receptor causes a conformational change in the postsynaptic membrane and generates an action potential.
✓ Step 6. this action potential travels through along the length of muscle fiber, and the penetrates deep into the muscle through the T-tubular system
✓ Step 7. The electric impulse stimulates the sarcoplasmic reticulum to release calcium
✓ Step 8. Calcium bind with troponin- C and activates myosin ATPase