Muscle Contraction physiology Flashcards Preview

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Flashcards in Muscle Contraction physiology Deck (13)
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1
Q

The interaction of myofibrils during contraction is known as:

A

Sliding filament theory of contraction

2
Q

What is the first step to muscle contraction?

A

Motor neuron releases its neurotransmitter (usually acetylcholine)

3
Q

Once the motorneuron is released

A

Acetylcholine diffuses across the synapse and touches the sarcolemma

4
Q

What two things happen once the neurotransmitter has touch the sarcolemma?

A

1) Sodium channels along sarcolemma open and sodium ions rush in
2) acetylcholine is broken down by acetylcholinesterase

5
Q

Once sodium ions have entered the interior of the muscle cell:

A

Transverse-tubules allow the sodium to travel throughout

6
Q

T-tubule

A

Structures that act as passageways for material in the sarcoplasm

7
Q

The presence of Sodium ions in the sarcoplasm causes:

A

Calcium ions to be released by sarcoplasmic reticulum

8
Q

What do calcium ions do?

A

Flood the sarcomere and bind to troponin

Troponin fall away from tropomyosin

9
Q

Once troponin falls away:

A

Tropmyosin slides off actin’s binding sites and cross-bridges form between actin and myosin

10
Q

Once cross-bridges have formed

A

Myosin heads pivot and pull actin to shorten sarcomere

11
Q

Once the sarcomere has shortened slightly

A

ATP is used to break present crossbridges and new ones form until desired contraction has occured

12
Q

After desired contraction has occured:

A

Calcium ions are pumped back into the sarcoplasmic reticulum

13
Q

Once calcium has returned to the sarcoplasmic reticulum

A

Troponin and tropomyosin return to their original position and block unwanted actin-binding sites