Lecture 10: Muscular Tissue Part 3

Question 1

muscle contraction requires both?

Answer 1

calcium and atp

Question 2

when myosin pulls on the thin filaments, z discs come together, the sarcomere shortens: the h zone? and the I band?

Answer 2

h zone disappears and i band narrows

Question 3

how do individual sarcomeres move bones?

Answer 3

sarcomeres shorten which pulls connective tissue which pulls tendons which moves bone

Question 4

what happens if the thick and thin filaments completely overlap?

Answer 4

no contraction

Question 5

what happens when the thick and thin filaments barely overlap?

Answer 5

myosin cant generate much tension due to lack of cross bridges

Question 6

signals from – stimulate action potential?

Answer 6

somatic motor neurons

Question 7

what is the name of the joint where neurons and muscles meet

Answer 7

neuromuscular junction

Question 8

somatic motor neurons release signals called?

Answer 8

neurotransmitters aka acetylcholine which bind protein receptors on muscle cells

Question 9

the na k bump keeps the inside of cells … positive or negative

Answer 9

negative on the inside because na moves out of cell and k moves into cell

Question 10

every cell maintains a…

Answer 10

negative resting membrane potential

Question 11

during an action potential the membrane potential becomes?

Answer 11

positive and this is called depolarization

Question 12

restoration of negative membrane potential is called?

Answer 12

repolarization

Question 13

what causes changes in membrane potential during action potentials?

Answer 13

plasma membrane transports

Question 14

voltage gated sodium channels allow ?

Answer 14

na to enter the cell: causes depolarization

Question 15

repolarization is the product of what?

Answer 15

voltage gated potassium channels : k flows out of the cell

Question 16

first step of how action potentials stimulate muscle contraction

Answer 16

1) the action potential travels along sarcolemma to VGCCs at t tubules
2) action potential opens the VGCCs and releases the calcium
3) calcium binds troponin and troponin moves tropmyosin off the myosin binding sites on thin filaments