B4: muscle contraction

Question 1

actin-myosin crossbridge cycle

Answer 1

interactions between actin and myosin shorten muscles to move the body

Question 2

motor neurons

Answer 2

propagate signals from the brain

Question 3

motor endplate

Answer 3

where nerve terminal meets the NMJ

Question 4

NMJ

Answer 4

motor neurons interact with muscles through a chemical synapse. acetylcholine is released into synaptic cleft

Question 5

sarcolemma

Answer 5

site of Ach binding on receiving muscle cell, which opens ion channels

Question 6

T-tubules

Answer 6

long invaginations in muscle cell membrane in which APs move

Question 7

sarcoplasmic reticulum

Answer 7

stores and releases Ca2+. Ca2+ released initiates actin-myosin crossbridge.

Question 8

tropomyosin

Answer 8

covers myosin binding sites in actin

Question 9

troponin

Answer 9

binds Ca2+ and causes conformational change of tropomyosin which causes myosin to be exposed to actin binding sites

Question 10

power stroke

Answer 10

powered by ATP cleaved when myosin releases ADP and Pi. allows myosin to pull itself along the actin filament