ch 10 pt 4 anatomy

Question 1

What happens when calcium enters at the synaptic knob?

Answer 1

Diffuses into synaptic knob and binds to proteins on surface of synaptic vesicles

Question 2

Nerve signal travels down axon and does what?

Answer 2

Opens voltage-gated Ca2+ channels

Question 3

What occurs when ACh is released from synaptic knob?

Answer 3

Vesicles merge with cell membrane at synaptic knob: exocytosis

Question 4

What is end-plate potential (EPP)

Answer 4

Na+ diffuses into the cell through the channels; leads to the opening of VGC in sarcolemma

Question 5

What is excitation-contraction coupling?

Answer 5

Stimulation of the fiber is coupled with the sliding of filaments; when there’s AP and can contract

Question 6

An action potential is what?

Answer 6

A rapid rise (depolarization) and fall (repolarization) in the charge of the membrane

Question 7

Na+ diffuses into what?

Answer 7

The cell through voltage-gated channels

Question 8

Cell repolarizes

Answer 8

Returns to -90mV

Question 9

Explain how AP travels down

Answer 9

AP goes to T-tubules to open Ca2+ channels, then Ca2+ to cytosol, then to troponin, then conformational change on tropomyosin and reveals actins active site

Question 10

What triggers crossbridge cycling?

Answer 10

When Ca2+ binds to troponin

Question 11

What breaks down crossbridge formation?

Answer 11

ATP binds to myosin

Question 12

What is crossbridge formation?

Answer 12

Myosin binds to actin active site