12. Muscle Form And Function

Question 1

What are the steps of muscle contraction?

Answer 1

1. Binding of myosin head to actin filament
2. Myosin head pivots and pulls actin towards M line, ADP and phosphate released
3. New ATP attaches to myosin head as it detaches
4. ATP split to ADP and Pi, myosin head cocked

Question 2

What ion is required for the contraction of muscles?

Answer 2

Ca2+, binds to troponin on actin filaments, changes shape and removes blocking action of tropomyosin. Actin active sites are exposed for myosin to bind

Question 3

What is isometric contraction?

Answer 3

Contraction in which no movement is produced. Ie standing, sitting, posture

Question 4

What is isotonic contraction?

Answer 4

Contraction which produces movement. Ie walking, moving any part of body
Concentric: muscle shorted as it contracts
Eccentric: muscle lengthens as it contracts (ie lowering dumbbell in bicep curl)

Question 5

What are isokinetic contractions?

Answer 5

Produce movement at a constant speed