Muscle Physiology Flashcards Preview

Medicine, Year 1 Block 5 (Musculoskeletal & Nervous System) > Muscle Physiology > Flashcards

Flashcards in Muscle Physiology Deck (19)
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1
Q

From largest to smallest, what is the levels of organisation of skeletal muscle?

A
Skeletal muscle
Muscle fascicle
Muscle fiber
Myofibril
Sarcomere
2
Q

What is the skeletal muscle surrounded by?

A

Epimysium

3
Q

What is the muscle fascicle surrounded by?

A

Perimysium

4
Q

What is the muscle fibre surrounded by?

A

Endomysium

5
Q

What is the myofibril surrounded by?

A

Sarcoplasmic reticulum

6
Q

The sarcomere is comprised of two filaments - what are they called?

A

Thick filaments: Myosin

Thin filaments: Actin

7
Q

A sarcomere is defined by what boundary?

A

Z line to Z line

8
Q

The centre of a sarcomere possesses which band and which line?

A

H band

M line

9
Q

Which large band surrounds the border of the H band?

A

The A band

10
Q

Which band surrounds the Z line?

A

I band

11
Q

What is the Myosin II molecule made up of?

A

Two heavy chains and a few light chains (head region) which binds to Actin and has ATPase activity

12
Q

What does the Actin filament comprise of?

A

Double stranded helical filamentous polymer of globular actin, with Tropomyosin reinforcing the structure. Attached to Tropomyosin is the Troponin complex (TnT, TnC, TnI). Also has a Ca2+ binding site

13
Q

Where does the Troponin usually attach to on the Actin filament?

A

On tropomyosin

14
Q

Describe what happens in Cross bridge cycling

A

The myosin heads attaches to the actin, and ATP binds to the myosin head. This causes dissociation of the actin-myosin complex. ATP is hydrolysed causing the myosin head to cock back and rest. A cross bridge forms the myosin head binds 12 nm along the actin. P from ATP is released, and the myosin head changes conformation resulting in the power stroke. ADP is then released and it returns to the attached state

15
Q

What is the neurotransmitter at the NMJ?

A

Acetylcholine

16
Q

What is the equivalent of a postsynaptic potential in the NMJ?

A

End plate potential

17
Q

What is the mechanism of tubocurare?

A

Nicotinic acetylcholine receptor antagonist

18
Q

What are the three phases of the Muscle Twitch?

A

Lag phase
Contraction phase
Relaxation phase

19
Q

Which bacteria causes Tetany?

A

Clostridium tetani