MUSCLES

Question 1

Which one is around a myofibril?

Answer 1

Endomysium

Question 2

When cardiac muscles start to contract?

Answer 2

Influx of the Ca2+ from the outside

Question 3

______________ from vagus nerve (CN 10) acts on the heart by lowering heart rate

Answer 3

Parasympathetic nerves

Question 4

Regulation of the contraction in smooth muscles?

Answer 4

Calmodulin

Question 5

Smooth muscle has __________ instead of troponin. All muscles has tropomyosin

Answer 5

calmodulin

Question 6

Ca+ binds to calmodulin, which activates ?

Answer 6

myosin light chain kinase

Question 7

ATPase activity for smooth muscle occurs by?

Answer 7

Myosin

Question 8

No T-tubules, poor SR, no troponin so ?

Answer 8

myosin is always ready to react & can hold long contractions

Question 9

What modulates smooth muscle action potential?

Answer 9

Acetylcholine

Question 10

What does Ach cause the erector pili to do?

Answer 10

increase Ca+ entering the cell to erects the muscle

Question 11

increase in intracellular Ca leads to what?

Answer 11

greater activation of contractile proteins

Question 12

Skeletal has__________ while smooth/cardiac = 1 nuclei

Answer 12

multinucleated cells

Question 13

Direct source of energy for skeletal muscle?

Answer 13

ATP –> ADP + phosphate

Question 14

How does ATP get transported out of the mitochondrial membrane?

Answer 14

ATP-ADP translocase

Question 15

Sarcolemma/ sarcomere is only in?

Answer 15

in straited muscle (skeletal & cardiac)

Question 16

Isotonic muscle contraction?

Answer 16

H & I band get shorter

Question 17

Increasing the load of muscles does what to velocity?

Answer 17

Slow down

Question 18

_______________________ is for stretch receptors (spindles), regulate stretch/muscle length & tone

Answer 18

Gamma efferent motor fibers

Question 19

Inorganic phosphate is released from ADP in myosin when?

Answer 19

For a powerstroke

Question 20

What is responsible for dissociation of phosphate group during muscle contraction?

Answer 20

Cocking action

Question 21

Myosin has ATPase action that turns ATP

Answer 21

ADP + Phospate, release of the phosphate groups causes the myosin powerstroke