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physiology Flashcards

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1
Q

functions of skeletal muscle

A

maintain posture, proposeful movement, resp movement, heat production, contribution to metabolism

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2
Q

describe skeletal muscle

A

straited and voluntary (innervated by somatic nervous system), no gp junctions, neurogenic initiation

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3
Q

where does the calcium from skeletal muscle come from

A

SR

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4
Q

what is the neurotransmitter in skeletal muscle

A

acetyl choline

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5
Q

what is straited and involuntary

A

cardiac muscle

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6
Q

what is unstraited and involunatry

A

smooth muscle

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7
Q

what is a motor unit

A

a single alpha motor neuron and all the skeltal muscle fibres in it innervates

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8
Q

what muscles have fewer motor fibres per motor unit

A

muscles for fine movements

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9
Q

how many fibres do muscles in the fingers and eyes have per motor unit

A

about 10

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10
Q

how many fibres do muscles for powerful movements have (the thigh)

A

100-1000 per motor unit

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11
Q

what does myocin look like

A

thick and dark

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12
Q

what does actin look like

A

thin and light

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13
Q

what does skeletal muscle consist of

A

parallel muscle fibres bundled by connective tissue - fibres usually extend the entire length of the muscle

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14
Q

what is myocin +actin

A

sacromere

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15
Q

what are sacromeres

A

functional units of muscle

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16
Q

what happens in sacromeres

A

actin slides over myocin which is ATP dependent

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17
Q

where is sacromere found

A

between two Z lines

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18
Q

what are the 4 zones of sacromeres

A

Abane, H zone, M line and I band

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19
Q

what happens in skeletal muscle fibres

A

Ca2+ is released from the lateral sacs of the SR when the surface action potential spreads down the transverse tubules

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20
Q

when is ATP needed

A

during muscle contraction (to power cross bridges) and during relaxation (to release cross bridges + to pump Ca2+ back into SR

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21
Q

what is a sign of death

A

rigor mortis

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22
Q

what is rigor mortis

A

when Ca2+ is pumped back into the SR

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23
Q

what does skeletal muscle tension depend on

A

the number of muscle fibres contracting and the tension developed by each contracting muscle fibre

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24
Q

in skeletal muscle what is shorterthe action potential or the resulting twitch

A

the action potential

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25
how can a stronger contraction be achieved in skeletal muscle
by summating twitches through repitive fast stimulation of skeletal muslce
26
what is tetanus
muscle fibre stimulated so rapidly it has no opportunity to relax
27
example of tetanus
lock jaw
28
why cant cardiac muscle be tetanus
due to long refractory period
29
what does increased frequency of stimulation of skeletal muscle do
lead to stronger contraction
30
how can maximum contraction be achieved
when the muscle is at its optimum length before the onset of contraction
31
what is isotonic contraction used for
used for body movements and moving objects
32
what happens in isotonic contraction
tension remains constant as the muscle strength changes
33
what happens in isometric contraction
used for supporting objects in fixed positions and maintain body posture
34
when does muscle tension develop in isometric contraction
at constant muscle length
35
Type 1 muscle contraction
slow oxidative
36
what is slow oxidative
slow contraction, high resistance to fatigue, low aerobic eg walking
37
straited muscles
skeletal and cardiac
38
cardiac muscle initiation of contraction is
myogenic
39
skeletal muscle initiation of contraction is
neurogenic
40
is the continuity of cytoplasm between nerve and skeletal muscle cells
no
41
what is a motor unit
a single alpha moor neurone and all the skeletal muscle fibres it innervates
42
levels of organisation of muscles
muscle, neuron, fibre, myofibril, sarcomere
43
what do Z lines do
connect the thin filaments of two adjoining sarcomeres
44
what is a t TUBULE
extensions of the membrane than dip into muscle fibre
45
what do motor units allow
simultaneous contraction of a number of muscle fibres
46
what helps to prevent muscle fatigue
asynchronous motor unit recruitment during sub maximal contractions
47
can cardiac muscle be tetanised
no
48
what is type IIa fibre
fast oxidative
49
what is type Iix fibre
last glycolytic
50
what are type 2 fires used for
aerobic and anaerobic metabolism and are useful in prolonged relatively moderate work activities
51
what is fast glycolytic fibres used for
anaerobic metabolism and are mainly used for short-term high intensity activities e.g. jumping
52
what is a reflex
a stereotypes response to a specific stimulus - they are the form of coordinated movement
53
what is a stretch reflex
a negative feedback that resists passive change in muscle length to maintain optimal resting length of muscle
54
what is a muscle spindle
sensory receptor in muscle stretch
55
what causes impaired skeletal muscle function
intrinsic disease of muscle, disease of NMJ, disease of lower motor neurons which supply the muscle, disruption of input into motor nerves
56
genetic causes of muscle disease
congenital myophathies, chronic degeneration, abnormalities in membrane ion channels
57
acquired causes in intrinsic msucle disease
inflammatory myopathies, non inflammatory, endocrine, toxic
58
symptoms of muscle disease
muscle weakness/tiredness, delayed relaxation after voluntary contraction, muscle pain, muscle stiffness
59
investigations of nueromuscular disease
emg, nerve conduction studies, muscle enzymes, inflammatory markers, muscle biopsy
60
what is a synovial joint seperated by
a cavity containing synovial fluid
61
what is a synovial joint united by
a fibrous capsule
62
what is the inner capsule of a synovial joint lined by
synovial membrane
63
what is the articular surafces of the bones invilved in a synovial joint covered by
carterlage
64
how much synovial fluid is in an adult knee
<3.5 ml
65
what does the synovial fluid do
lubricates, facilitates ovements, minimises wear and tear, aids in nutrition of articular cartilage, supplies chondrocytes with O2 and nutrients
66
rapid movement means what for viscosity and elasticity
decreased viscosity and increased elasticity
67
what colour is synovial fluid
clear
68
what is articular cartiage usually
hyaline
69
descrbe hyaline cartilage
elastic sponge liek
70
what does articular cartilage have
special extracellualr matrix
71
what is the extracellular matrix of articular joints made of
water, collagen, proteroglycans
72
what is the extra cellular matrix madeand degraded by
chondrocytes
73
markers of cartilage degradation
serum and synovial keratin sulphate
74
what type of arthtritis is this - wear and tear, carrtilage and synovial composition and synocial composition and function deteriorate with age
osteoarthritis
75
what type of arthritis is this synovial cell proliferation and inflammation
rheumatoid
76
what type of arthritis is this- deposition of salt crystals
gouty arthtritis
77
what is the diagnosis of this - injury and inflammation to periaticular structures
soft tissue rheumatism
78
3 types of joints
synovial, fibrous, cartilaginous
79
what is synovial fluid made from
it is derived from hyaluronic acid
80
what type of collagen decreases with age
type 2
81
what is transduction of pain
translation of noxious stimulus into electrical activity at the peripheral receptor
82
what is transmission of pain
the propagation of pain signal as nerve impulses through the nervous system
83
what is the modulation of pain
modification/hindering of pain transmission in the nervous system
84
what is the perception of pain
conscious experience if pain
85
what are nociceptors
primary sensory afferent neurones normally activated by intense noxious stimuli
86
what type of neurones are nociceptors
first order neurones
87
where do second order neurones ascend from
the spinal cod in the anterolateral system
88
where do second order neurones terminate
in the thalamus
89
what are the major nociceptors
sensory afferent neurons atvated by intense noxious stimuli
90
myelination of a fibres
thin
91
myelinaton of c fibres
unmyelintated
92
where do alpha neurons recieve input from
upper motor neurons of the brain, sensory inputs from muscle spindles spinal interneurones
93
what are alpha nuerones directly responsible for
generation of force by muscle
94
what makes a motor unit
alpha motor neurone + muscle
95
where does the alpha motor unit communicate with muscle fibre
at the NMJ
96
what is the mechanism by which cells communicate electrically with one another across the synaptic celft
synaptic transmission
97
two forms of synaptic transmission
electrical or chemical
98
what does a gap junction consist of
two hemichannels
99
what do gap junctions permit the passage or
small molecules (<1KdA)
100
how does orthodromic synaptic transmission proceed
with limited delay

MSK (19 decks)

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