Muscle Physiology (Continued) (Exam 3)

Front 1

how does muscle contraction work?

Back 1

motor neuron AP --> ACh released --> synaptic transmission --> large EPSP --> muscle AP

Front 2

conduct APs deep into the muscle fiber

Back 2

T-tubules

Front 3

these receptors function as voltage sensors, activated by muscle AP

Back 3

DHP receptors

Front 4

stores Ca2+ and releases it to myofilaments

Back 4

sarcoplasmic reticulum

Front 5

these receptors function as Ca2+ channels

Back 5

ryanodine receptors

Front 6

-this is released through RyR channels activates muscle contraction

Back 6

Ca2+

Front 7

these pumps actively transport Ca2+ back into the SR

Back 7

Ca2+ pumps

Front 8

explain the sequence of events in excitation-contraction coupling

Back 8

1. muscle AP travels down the T-tubules
2. DHP receptors on the T-tubule are activated, interact with RyR on the SR
3. RyR Ca2+ channels open
4. Ca2+ diffuses out of the SR into the cytosol and to the thin filaments
5. Ca2+ binds to troponin, which pulls tropomyosin off the myosin binding site
6. myosin binds to actin --> sarcomere contracts
-when APs stop, Ca2+ is pumped back into SR --> sarcomere relaxes

Front 9

three types under whole muscle contraction

Back 9

1. twitch
2. summation
3. tetanus

Front 10

single rapid muscle contraction

Back 10

twitch