TSM 1.12

Question 1

what happens after muscle action potential?

Answer 1

• down special invaginations of sarcolemma
• reach sacroplasmic reticulum
• release calcium

Question 2

what type of calcium channel is on the t-tubule sacrolemma?

Answer 2

L-type channel

Question 3

what receptor is on the sacroplasmic reticulum calcium channel?

Answer 3

ryanodine receptor

Question 4

what is the connection between calcium channel on t-tubule and Sacroplasmic reticulum?

Answer 4

electromechanical coupling

Question 5

what is troponin T for?

Answer 5

binds tropomyosin

Question 6

What is troponin C for?

Answer 6

calcium binding

Question 7

what is troponin I for?

Answer 7

actin binding

Question 8

how many heavy chain does myosin have?

Answer 8

1

Question 9

how many light chain does myosin have?

Answer 9

2

Question 10

what is on the heavy chain?

Answer 10

• rod
• hinge
• head

Question 11

what is on the light chain?

Answer 11

• alkaline - stabilising head

- regulatory - regulates ATPase activity

Question 12

what does desmin do?

Answer 12

scaffolds Z-line

Question 13

what does titin do?

Answer 13

anchors myosin to Z-line

Question 14

what does alpha-actinin do?

Answer 14

anchors actin to Z-line

Question 15

what does myomesin do?

Answer 15

anchors tail of myosin to form m-line

Question 16

what are the stages of muscle contraction?

Answer 16

• release calcium from SR
• calcium binds to troponin C
• conformational change
• troponin I release from actin
• troponin T moves tropomyosin from myosin
• myosin head free to interact with actin

Question 17

describe cross bridge cycling

Answer 17

1) atp binds to myosin head
2) myosin dissociates from actin
3) ATP hydrolysed
4) myosin moves to cocked state
5) myosin binds to new place on actin
6) phosphate released
7) power stroke
8) sliding filaments
9) ADP released