Excitation-Coupling

Question 1

Sac-like bulges around the T-Tubule are called ____________

Answer 1

Terminal Cisternae

Question 2

Action potential travels across the entire ___________ and is rapidly conducted into the interior of the muscle fiber by structures called ___________

Answer 2

Sarcolemma, T-Tubules.

Question 3

Calcium is released from the sarcoplasmic reticulum into the ____________

Answer 3

Sarcoplasm

Question 4

The process of excitation-contraction coupling is used for

Answer 4

Converting action potential in a muscle fiber to a contraction.

Question 5

First stage of the four step process -

Answer 5

Cross bridge formation. Energized myosin head attaches to the actin myofilament.

Question 6

Second stage of the four step process -

Answer 6

The power stroke - ADP and Pi are released, head pivots and pulls actin filament toward midline.

Question 7

Third stage of the four step process -

Answer 7

Cross bridge detachment - After ATP attaches to the myosin head, link between myosin and actin weakens, and the formed cross bridge detaches.

Question 8

Fourth stage of the four step process -

Answer 8

Cocking of the myosin head - As ATP is hydrolyzed to ADP and Pi, the myosin head returns to it’s pre-stroke high energy or “cocked” position.