Cross-bridge Cycling / Sacromere Shortening

Question 1

In resting skeletal muscle, ______ is attached to myosin binding site therefore _______ and tropomyosin inhibit ________ interaction

Answer 1

Troponin I; troponin I; myosin-actin

Question 2

The process of depolarization of muscle fiber initiates ______

Answer 2

Contraction

Question 3

In excitation-contraction coupling, AP is transmitted to T-tubules and the ______ of T-tubules causes conformational change in _____ receptor then leading to conformational change in _____ receptor, opening channels triggering ______ release from terminal cisternae of ______

Answer 3

Depolarization; Dihyropridine receptor (DHPR), Ryanodine receptor (RyR); Ca++, L-tubules

Question 4

Released Ca++ binds to ____ which facilitate the movement of associated tropomyosin. The tropomyosin moves away exposing ___ binding site which triggers ________

Answer 4

Troponin C; myosin binding site, cross bridge cycling

Question 5

Active pumping of ____ back into _____ bring to relaxation

Answer 5

Ca++, SR

Question 6

In troponin-tropomyosin interaction, Ca++ from ____ binds to Troponin C which induce conformational change which result in shifting of troponin __ that allow tropomyosin to move exposing binding site

Answer 6

SR; Troponin I

Question 7

Change in position of _______ drags tropomyosin away and the ______ interact with actin engaging ________

Answer 7

Troponin T; myosin head, cross-bridge cycling

Question 8

Increase in ____ concentration in cytoplasm triggers the _____

Answer 8

Ca++, contractile process

Question 9

______ in Ca++ concentration in cytoplasm** detaches Ca++** from _____ turning off cross-bridge cycling

Answer 9

Decrease, troponin