physiology

Question 1

functions of skeletal muscle

Answer 1

• posture
• movement
• respiratory movement
• heat production
• whole body metabolism

Question 2

is smooth muscle striated

Answer 2

no

Question 3

is skeletal muscle neurogenic or myogenic

Answer 3

neurogenic

Question 4

is there a neuromuscular junction in skeletal or cardiac muscle

Answer 4

skeletal

Question 5

what is the transmitter at a neuromuscular junction

Answer 5

acetylcholine

Question 6

what is a motor unit

Answer 6

it encompasses all the muscle fibres innervated by a single alpha motor neuron

Question 7

what is the sarcomere

Answer 7

the functional unit of skeletal muscle

Question 8

what are the four zones in sarcomere

Answer 8

A band
H zone
M line
I band

Question 9

is actin thin or thick

Answer 9

thin

Question 10

is myocin thin or thick

Answer 10

thick

Question 11

in sliding filament theory, what is force generation dependant on

Answer 11

ATP-dependant interaction between myosin and actin

Question 12

what is excitation contraction coupling

Answer 12

the process whereby the surface action potential results in activation of the contractile structures of the muscle fibre

Question 13

why is there no cross bridge binding when the muscle fibre is relaxed

Answer 13

because the cross-bridge binding on the actin is physically covered by the troponin-tropomyosin complex

Question 14

what happens when muscle fibre is excited

Answer 14

calcium binds with troponin pulling troponin-tropomyosin complex aside to expose cross bridge binding site - cross bridge binding occurs

Question 15

where is Ca++ derived from

Answer 15

sarcoplasmic reticulum in skeletal muscle

Question 16

what is ATP needed for during relaxation

Answer 16

to release cross bridges and to pump calcium back into the sarcoplasmic reticulum

Question 17

is a single twitch useful

Answer 17

no need a double twitch

Question 18

when is maximal tetanic contraction achieved

Answer 18

when the muscle is at its optimal length before the onset of contraction

Question 19

isotonic muscle contraction

Answer 19

muscle tension remains constant as the muscle length changes

Question 20

isometric muscle contraction

Answer 20

muscle tension develops at constant muscle length

Question 21

what are some metabolic pathways that supply ATP in muscle fibre

Answer 21

• transfer of high energy phosphate from creatine phosphate to ADP
• oxidative phosphorylation
• glycolysis

Question 22

what are slow oxidative type 1 fibres used for

Answer 22

prolonged relatively low work aerobic activities

Question 23

three types of joints

Answer 23

synovial
fibrous
cartilaginous

Question 24

fibrous joint

Answer 24

• bones united by fibrous tissue

- doesnt allow any movement

Question 25

cartilaginous joint

Answer 25

allow limited movement | -intervertebral discs

Question 26

synovial joints

Answer 26

- separated by a cavity and united by a fibrous capsule | - knee

Question 27

what are simple and compound synovial joints

Answer 27

simple - one pair of articular surfaces | compound - more than one pair of articular surface

Question 28

what is joint lubrication provided by

Answer 28

- cartilage interstitial fluid - synovium - synovium-derived lubrcin

Question 29

functions of synovial fluid

Answer 29

- lubricates joint - facilitates joint movements - helps minimise wear and tear of joints - aids in nutrition of articular cartilage - supplies chondrocytes with O2 and nutrients and removes CO2 and waste products

Question 30

does synovial fluid have high or low viscosity

Answer 30

high

Question 31

what is rapid joint movement associated with in terms of viscosity and elasticity

Answer 31

decreased viscosity and increased elasticity

Question 32

viscosity of inflammatory synovial fluid, high or low

Answer 32

low

Question 33

functions of articular cartilage

Answer 33

- low friction lubrication | - distributes contact pressure to subchodral bone

Question 34

4 zones of cartilage

Answer 34

- superficial zone - middle zone - deep zone - calcified bone

Question 35

what are the mechanical properties of the cartilage

Answer 35

water collagen proteoglycan

Question 36

what is the extracellular matrix of the articular cartilage synthesised, organised, degraded and maintained by

Answer 36

chondrocytes

Question 37

what can happen if the rate of ECM degradation exceeds the rate of its synthesis

Answer 37

joint disease

Question 38

what are the catabolic factors of cartilage matrix turnover and what do they do

Answer 38

tumour necrosis factor (TNFalpha) IL-1 they stimulate proteolytic enzymes and inhibit proteoglycan synthesis

Question 39

what are the anabolic factors of cartilage matrix turnover and what do they do

Answer 39

Stimulate proteoglycan synthesis and counteract effects of IL-1 Tumour growth factor (TGF)-β Insulin-like growth factor (IGF)-1

Question 40

definition of pain

Answer 40

An unpleasant sensory and emotional experience, associated with actual tissue damage or described in terms of such damage

Question 41

what are the four processes in the physiology of pain

Answer 41

- transduction - transmission - modulation - perception

Question 42

what is tranduction

Answer 42

translation of noxious stimulus into electrical activity at the peripheral nociceptor

Question 43

what is transmission

Answer 43

propagation of pain signal as nerve impulses through the nervous system

Question 44

what is modulation

Answer 44

modification/hindering of pain transmission in the nervous system e.g. by inhibitory neurotransmitters like endogenous opioids

Question 45

what is perception

Answer 45

Conscious experience of pain. Causes physiological and behavioural responses

Question 46

what does pain begin with

Answer 46

the activation of nociceptors

Question 47

what are nociceptors

Answer 47

they are specific primary sensory afferent neurones normally activated by intense noxious stimuli Nociceptors are first order neurones that relay information to second order neurones in the CNS by chemical synaptic transmission

Question 48

what do the second order neurons do

Answer 48

ascent the spinal cord in the anterolateral system (terminate in the thalamus)

Question 49

what does the anterolateral system compose of

Answer 49

- the spinothalamic tract | - the spinoreticular tract

Question 50

what is the STT involved in

Answer 50

pain perception

Question 51

what is the SRT involved in

Answer 51

autonomic responses to pain, arousal, emotional responses, fear of pain

Question 52

where is the sensory information relayed to from the thalamus

Answer 52

via third order neurons to the primary sensory cortex

Question 53

what are the different types of fibres in nociceptors

Answer 53

Adelta fibres | C fibres

Question 54

what are A delta fibres

Answer 54

are mechanical/thermal nociceptors that are thinly myelinated (conduction velocity of 6.0-30.0 ms-1 ) - respond to noxious mechanical and thermal stimuli. Mediate ‘first’, or fast, pain

Question 55

what are C fibres

Answer 55

are nociceptors that are unmyelinated (conduction velocity of 0.5-2.0 ms-1) – collectively they respond to all noxious stimuli (e.g. they are polymodal). Mediate ‘second’, or slow, pain

Question 56

what are the 4 ways to classify pain

Answer 56

- mechanisms - time course - severity - source of origin

Question 57

what is nociceptive pain usually in response to

Answer 57

injury of stimulus by noxious stimuli | only provoked by intense stimulation of nociceptors

Question 58

what is neuropathic pain caused by

Answer 58

damage to neural tissue

Question 59

examples of dysfunctional pain

Answer 59

IBS, tension headache, interstitial cystitis

Question 60

what is referred pain caused by

Answer 60

caused by convergence of nociceptive visceral and skin afferents upon the same spinothalamic neurons at the same spinal level