Muscle

Question 1

Contractile components of smooth muscle

Answer 1

actin and myosin, no troponin

Question 2

Contractile components of skeletal muscle

Answer 2

actin and myosin, troponin

Question 3

Role of Ca++ in smooth muscle contraction

Answer 3

enters cell via ECM, binds to calmodulin, activates MLCK

When Ca++ decreases, MLCK is downregulated and you get relaxation

Question 4

Function of MLCK

Answer 4

phosphorylates myosin, which activates myosin ATPase which allows binding of actin and myosin

Question 5

Difference between power stroke of smooth and skeletal muscle

Answer 5

in smooth the power stroke continues as long as myosin is phosphorylated

Question 6

Role of Ca++ in skeletal muscle contraction

Answer 6

binds TnC, which moves tropomyosin, exposing active site on actin for myosin binding

Question 7

Function of ATP in skeletal muslce contraction

Answer 7

binds head of myosin, converts to ADP +Pi, causing myosin head to pivot to line up with new actin monomer. Pi released, trigger power stroke

Question 8

How does Ca__ affect electrical events

Answer 8

Ca++ influx causes depolarization