physiology Flashcards

1
Q

what is the function of skeletal muscles

A
maintain posture
respiration
heat production (shivering)
metabolism
movement
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2
Q

what are the 3 types of muscle

A

cardiac
skeletal
smooth

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3
Q

describe cardiac muscle

A

striated and involuntary

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4
Q

describe smooth muscle

A

non-striated and involuntary

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5
Q

describe skeletal muscle

A

striated and voluntary

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6
Q

what innervates cardiac muscles

A

ANS

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7
Q

what innervates smooth muscles

A

ANS

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8
Q

what innervates skeletal muscle

A

somatic nervous system,

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9
Q

what is the transmitter at the skeletal muscle neuromuscular junction

A

acetylcholine

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10
Q

what initiates skeletal muscle

A

neurogenic mechanism

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11
Q

what initiates cardiac muscle

A

myogenic (pacemaker potenital)

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12
Q

what is a motor neurone

A

a single alpha motor neurone and all the skeletal muscle fibres that it innervates

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13
Q

what does the number of muscle fibres per motor unit depend on

A

the function served by the muscle. if precision is more important than power then there will be fewer fibres and vice versa

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14
Q

how are skeletal muscles organised

A

whole muscle to muscle fibre to myofibrils to sarcomere which are made up of myosin and actin

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15
Q

what is a myofibril

A

a specialised intracellular structure

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16
Q

what is a functional unit

A

the smallest component capable of performing the functions of the organ

17
Q

where is a sarcomere located

A

between two z-lines

18
Q

what is a z-line

A

connects the thin filaments of two adjoining sarcomeres

19
Q

what are the 4 zones of a sarcomere

A

A-band
H-zone
M-line
I-band

20
Q

what is a A-band

A

thick filaments with portions of thin that overlap both ends of the thick

21
Q

what is the H-zone

A

lighter areas within the middle of the A-band where the thin filaments don’t reach

22
Q

what is the M-line

A

extends vertically down the middle of the A-band, within the centre of the H-zone

23
Q

what is the I-band

A

consists of the remains portion of thin filaments that don’t project onto the A-band

24
Q

how is muscle tension produced

A

the sliding of actin on myosin

25
what is ATP needed for in muscle contraction
contraction relaxation to release cross bridges pump Ca2+ back into the SR
26
what is Ca2+ needed for in muscle contraction
switch on cross-bridge formation
27
what is excitation contraction coupling
the process where the surface AP results in activation coupling of the contractile structures of muscle fibres
28
explain muscle contraction
acetylcholine is released by the motor neurone the surface AP spreads down the transverse T-tubles this triggers the release of Ca2+ from the SR Ca2+ binds to troponin which pulls the troponin-tropomysoin complex aside to expose the bind site cross-bridge formation occurs