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Flashcards in Contraction of the muscle Fiber Deck (47):
1

The 3 structures that are directly controlling the muscle contraction

Muscle
Nerve
Synapse

2

Theory stating that muscle contraction is based on shortening of sarcomeres throughout the skeletal muscle. Because sarcomeres are end to end, all the way down the length of the skeletal muscle cell, the muscle cell shortens too.

Huxley's Sliding Filament Theory

3

Huxley's Sliding Filament Theory predicts that thick and thin filaments must overlap and slide past one another. Greater overlap = shorter or longer muscle?

Shorter Muscle

4

Contractile element that is made of myosin that has hinged tail and 2 heads which are capable of flexing

Thick Filament

5

What two binding sites are on the heads of myosin?

ATP and Actin binding sites

6

Name the 3 components of thin filament

Actin
Tropomyosin
Troponin Complex

7

There is a binding site on the actin molecules for

myosin

8

Two additional things that are necessary for contraction to occur

Calcium Ions
ATP

9

When a muscle is relaxed, is there maximal or minimal filament overlap?

Is there action potential from the nerve?

Minimal

No.

10

"Activated" myosin heads are holding...

ADP and inorganic phosphate after hydrolization from ATP

11

Is the ATP kinetic or potential energy?

Potential

12

Is there Ca in the cytoplasm surrounding microfibrils?

No

13

Where does the Calcium come from?

Terminal cisternae of the sarcolplasmic reticulum

14

What causes the calclium to enter the cytoplasm and surround the myofibrils?

Action potential along the nerve

15

What does Ca bind with in the myofibril?

Troponin

16

What happens to the troponin once Ca binds with it?

It changes shape

17

What is troponin attached to?

Tropomyosin

18

What forms when the myosin (charged) binds to actin (thick and thin filament of myosin head binds to actin)

Cross Bridge Attachment

19

Flexion of myosin head an tail that pulls thin filament along after cross bridge attachment

Power Stroke

20

What happens when the power stroke goes on the entire sarcomere?

Sarcomere Shortening

21

What occurs next, a process that requires ATP binding to the myosin head?

Cross Bridge Detachment

22

Where does ATP come from?

Cytoplasm

23

What cleaves the ATP into ADP and inorganic phosphate?

Myosin ATPase

24

What does cleaving of ATP into ADP by myosin ATPase achieve?

Storage of the potential energy in the myosin head for next cross bridge

25

What if there is no more contraction/action potential to occur?

Returns to relaxed state

26

What happens to Ca and ATP if there is no more contraction to occur

Calcium goes to terminal cysternae
ATP be bound to myosin head

27

Which step of sarcomere shortening actually uses ATP?

Power stroke

28

Structure that tells the muscle what to do and when to do it

Motor nerve

29

Axon of nerve comes from spinal chord and expands into three

terminal boutons

30

Terminal bouton contains these, which are contained within it

Synaptic Vesicles

31

Neurotransmitter which functions as ligand within terminal bouton

Acetylcholine

32

Channels in terminal bouton in addition to typical Na and ATPase channels (maintenance proteins)

Ca channels

33

Muscle side of neuromuscular junction that contains sarcolemma is called

Motor End Plate

34

What formation occurs on the motor end plate to increase surface area?

Junctional Folds

35

Within junctional folds are receptors for acetylcholine

Ach Receptors

36

The space between the nerve and muscle that has glycoproteins to hold structures in place

Synaptic Cleft

37

Action potential causes what to change in the plasma membrane of the terminal bouton

Voltage Change

38

The voltage change causes opening of which voltage gated channels to allow its movement from outside bouton to inside the bouton?

Calcium Voltage Gated Channels

39

What does the calcium cause when its released in the terminal bouton?

Vesicle migration

40

When vesicles reach end of terminal boutons, what occurs?

Exocytosis of acetocholyne

41

Acetylcholine crosses the synapse and binds with what on the motor end plate?

Receptors

42

What does acetycholine migration across the membrane cause?

Graded potential (Na+ flows in)

43

What follows the graded potential?

Action potential along membrane of skeletal muscle

44

How is acetylcholine removed to stop action potentials from recurring?

Acetylcholinesterase

45

Means when you excite the cell a contraction will follow

Excitation-Contraction Coupling

46

What structure of muscle cell is exciteable and brings the action potential to the muscle fibers?

T-tubules

47

What is released after excitation of t-tubules?

Calclium voltage gated channels in terminal cysternae open and Ca diffuses