Muscle Fiber Contraction: Classwork Flashcards Preview

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Flashcards in Muscle Fiber Contraction: Classwork Deck (22)
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1
Q

whats molecular composition of myofilaments

A

other proteins help form the structure of the myofibril - also maintains alignment of sarcomere

2
Q

what 3 things consist in molecular composition of myofilaments

A

Elastin filament dystrophin nebulin

3
Q

Elastin filament

A

composed of protein titin -holds thick filaments in place; helps recoil after stretch; resists excessive stretching

4
Q

Dystrophin

A

links thin filaments to proteins of sarcolemma

5
Q

Nebulin

A

myomesin, C proteins binf filaments or sarcomeres together

6
Q

Whats the sarcoplasmic reticulum

A

network of smooth endoplasmic recticulum tubules surrounding each myofibril

7
Q

list 4 things about the sarcoplasmic recticulum

A

-most run longitudinally -terminal cisterns form perpedicular cross channels at the A-I band junction -SR functions in regulation of intracellular levels -Stores and releases calcium

8
Q

what are t tubules

A

tube formed by protrusion of sarcolemma deep into cell interior - penetrate cell’s interior at each A-I band junction between terminal cisterns

9
Q

what do t tubules do

A

increase muscle fiber’s surface area greatly lumen continous w/ extracellular space allow electrical nerve transmissions to reach deep into interior of each muscle fiber

10
Q

Triad

A

area formed terminal cistern one sarcomere, T tubule, and terminal cisterns of neighboring sarcomere

11
Q

whats a triad relationship

A

when an electrical impulse passes by, T tubule proteins change shape, causing SR proteins to change shape, causing release of calcium into cytoplasm

12
Q

contraction

A

the activation of cross bridges to generate force

13
Q

shortening

A

occurs when tension generated by cross bridges on thin filaments exceeds forces opposing shortening

14
Q

contraction ends

A

when cross bridges become inactive

15
Q

what happens in the relaxed state

A

thin and thick filaments overlap only slightly at end of A band

16
Q

describe a Sliding filament

A

model of contraction stares that during contraction, thin filaments slide past thick filaments, causing actin and myosin to overlap more

17
Q

in sliding filaments what doesnt change length

A

neither thick nor thin filaments change length, just overlap more

18
Q

what occurs in the nervous system that causes contraction

A

when the nervous system stimulates muscle fiber, myosin heads are allowed to bind to actin, forming cross bridges, which cause sliding (contraction) to begin

19
Q

what happens when cross bridge attatchments form and break several times?

A

each time oulling thin filaments a little closer toward center of sarcome in a ratcheting action -causes shortening of muscle fiber

20
Q

name which bands and lines are pulled together in contraction

A

Z discs are pulled toward M line I bands shorten Z discs become closer H zones disappear A bands move closer to each other

21
Q

just look at the gif

A

just look at it

22
Q

just look at it

A

just look at it