Bits and Pieces Flashcards

1
Q

What is the difference between a generalised and a localised system, give an example of each.

A

Generalised - distrib through body i.e. cardiovascular

Localised - in one area only i.e. reproductive

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2
Q

What is the difference between the carotid artery and the jugular vein

A

Carotid: heart to head
Jugular: head to heat

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3
Q

Give examples of amorphous extracell. and fibrous extracell. material

A

Amorphous: jelly like - blood, lymph or solid - cartilage and bone
Fibrous: collagen, reticular, elastic

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4
Q

What can be found on the apical, lateral and basal surfaces of epith. cells

A

apical: cilia, microvilli, stereocilia
lateral: interdigitation or junctional complexes
basal: striations, basement membrane, hemidesmosomes

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5
Q

What are the embryonic origin layers for skin, gut and cavities?

A

Skin: ectoderm
Gut: endoderm
Cavities: mesoderm

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6
Q

What is the difference between flexion, extension and hyperextension in terms of body movement (feet/hands)

A

flexion; folded up like when asleep

extension: straight line from ante brachium/crus
hyperextension: dorsal flexion/plantigrade stance

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7
Q

The pectoral limb: scchurc’mp

probs of no help but to me :)

A

scapula, clavicle, coracoid, humerus, ulna, radius, carpal bones, metacarpals, phalanges

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8
Q

The pelvic limp: iiapfpft’mp

probs of no help but to me :)

A

ilium, ischium, acetabular bone, pubis, femur, patella, fibula, tibia, tarsal bones, metatarsal, phalanges

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9
Q

What solutes are high intracellularly?

A

K+, Mg2+, phosphates, proteins,

maintained by active transport

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10
Q

What solutes are high extracellularly?

A

Na+, Cl-, Ca2+, HCO3-

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11
Q

Where are discontinuous capillaries found?

A

bone marrow, liver and spleen - permeable to large molecules

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12
Q

What three things make up ficks law

A

SA, conc. difference, thickness of diffusion pathway

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13
Q

List the 4 functions of the lymphatic system

A

1) control blood vol and extract vol (return oncotic protein to blood)
2) absorption of fat
3) immune surveillance
4) metabolism and turnover of extracell matrix constit

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14
Q

Where is there no lymphatic tissue?

A

CNS, eye and bone

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15
Q

What is lymphodema? How does it occur?

A

obstruct of lymph drainage = build up of lymph fluid can be from lack of sufficient lymph vessels, radiotherapy destroyed or surgery

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16
Q

Where do platelets come from?

A

fragments of megakaryocytes from one marrow

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17
Q

What is a Heamopoietic stem cell and how is it controlled?

A

multipotent precursor of amyloid, lymphoid or erythroid cells.
regulated by stream fibroblast, osteoblast, endoth, cell and extracell matrix - receptor binding needed

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18
Q

What are the three roles of EPO

A

shortens cell cycle
increases rate of maturation
increases rate of release from bone marrow

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19
Q

Why and where is EPO released from?

A

from kidney

why: fall of RBC’s, tissue hypoxia

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20
Q

How do platelets form? What stimulates this?

A

megakaryocytes increase DNA and cytoplasmic volume –> platelets bud off
stimulated by thrombopoietin (TPO)

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21
Q

Where are monocytes stored

A

they are not stored - released into blood after production

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22
Q

List the four things the immune system requires to be functional

A

1) inactivity to itself
2) specificity - be able to recognise non-self
3) recognition of microbes and proteins - antigens, PAMPS
4) be able to destroy foreign/abnormal material - phagocytosis

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23
Q

Where are B cells derived from?

A

bone marrow, peyers patches in ruminants and bursa of Fabricius in birds

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24
Q

How does mast cell action vary between GI tract, Airways and Blood vessels?

A

GI tract: increase fluid secretion and peristalsis
Airways: decrease diameter, increase mucus
Blood vessels: increase blood flow, increase permeability = higher lymph flow

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25
Q

What are some common autacoids?

A
  • histamine
  • bradykinin and substance P –> vasodilation, itch and pain
  • cytokines
  • Eicosanoids - PGs, thromboxanes and leukotrienes
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26
Q

How can leukocytes migrate into tissue to cause inflam?

A

toxins and proinflam cytokines activate endothelium = expression of cell adhesion molecules = leukocytes stick and slowed down –> emigration into tissue where they release enzymes and ROS = clear dead tissue and microbes (init good)

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27
Q

What are the differences between serous, catarrhal, fibrinous and suppurative inflam?

A
  • serous - minimal increase in permeabil. forms serous exudate
  • catarrhal - exudate formed on mucosal surface. serous fluid with mucus, inflam cells and cell debris
  • fibrinous - greater permeabil fibrinogen out = fibrin –> yellow gel like bread and butter
  • suppurative = pus, thick and creamy with neutrophils
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28
Q

What is a phlegmon?

A

diffuse suppurative inflammation in loos connective tissue (cellulitis)

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29
Q

What is an empyema?

A

assume of pus in body cavity

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30
Q

What cell population change happens in chronic vs acute inflam?

A

neutrophils –> macroph. (3 days) to lymphocytes and plasma cells (7-10 days)

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31
Q

What does granulation tissue look like - is it the same as granulomatous inflammation? When does it occur?

A

Not the same as granulomatous inflammation = macrophage rich
It is pink, soft, moist and bumpy, well vascularised (angiogenesis occurs) but no nerves = no pain. It occurs in the repair of inflammation - fibroblasts eventually migrate through = fibrin scaffold and collagen.

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32
Q

What is the difference between primary and secondary intention healing?

A

primary - if directly opposing wound edges
secondary - extensive tissue loss need greater volume of granulation tissue, more extensive scar contraction - may restrict movement

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33
Q

What is proud flesh?

A

excessive proliferation of granulation tissue, tumour like masses

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34
Q

What is keloid?

A

unsightly proliferation of scar tissue - very dense collage

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35
Q

How can a low energy balance cause hydraulic degeneration?

A

Na+/K+ ATPase is the main regulator for electrolyte balance that then drives water uptake/exit. With low energy this ATPase doesn’t function

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36
Q

What happens to fatty acids that enter the liver?

A
  • oxidised in mitochondria
  • used for cholesterol and phospholipids
  • oxidised to ketone bodies
  • esterified to make VLDL to go into circulation
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37
Q

How is VLDL made and what problem occurs if a step is compromised?

A

fatty acid –> esterified to triacylglyceride –> bound with apoprotein —> packed into VLDL –> circulation
if this is compromised (apoprotein synthesis or packaging into VLDL) = fatty change

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38
Q

What does a corticosteroid do?

A

induces transcription of glycogen synthetase = excessive storage of glycogen = steroid hepatopathy

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39
Q

What are hyaline droplets and what do they stain as?

A

they are accumulations of proteins within cytoplasm. Eosinophilic staining.

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40
Q

What do glyoproteinoses, sphingolipidoses, glycogenoses and ceroid-lipofuscinoses have in common?

A

All inherited lysosomal storage disorders where substrate cannot be broken down (enzyme disfunction/absence or absence of activator protein) - accumulate in lysosome

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41
Q

Can lysosomal storage disorders be acquired?

A

Yes - exogenous toxins such as swainsonin/alkaloid inhibiting lysosomal alpha mannosidase

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42
Q

How can you identify amyloidosis?

A

It is an amorphous, eosinophilic extracell. material. Stains red with Congo red stain.

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43
Q

What are the two main forms of necrosis?

A

a) oncotic = death by swelling, membrane breakdown = leak. More common and pathological, involves immune response.
b) apoptosis = cell suicide, death by shrinkage - chromatin, fragmentation –> phagocytosis.

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44
Q

What is the pathogenesis of Apoptosis?

A

Suicide - uses cells own caspase enzymes –> cleaves cytoskeletal proteins, activates endonuclease, cleaves nuclear proteins. Flipping of phospholipid membrane = abnormal –> phagocytosis

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45
Q

What is the pathogenesis of oncotic necrosis?

A

cell membrane injury = influx of calcium into cell = intracellular messenger and enzyme activator.
- phospholipases active = membrane destruction
- Atlases accelerate ATP depletion
- proteases - destruct membrane and cytoskeleton
- endonucleases - degrade nuclear chromatin
Cell death = release of cellular contents - stimulate immune response. Degradation by own lysosomal enzymes (autolysis) or recruited leukocytes (heterolysis)

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46
Q

List the three different appearances of the nucleus

A

pyknosis: shrunken, dark staining
karyorrhexis: rupture of nuclear envelope
karyolysis: fading nucleus (RNA/DNAases)

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47
Q

How can you grossly see oncotic necrosis?

A
Sharply demarcated from viable tissue as active inflamm reaction. 
red border (hyper perfusion), internal white border (leukocytes with lysosomal enzymes)
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48
Q

What are the two types of gangrenous necrosis, what do both stem from?

A

Both from coag necrosis.

1) dry - mummified by dehydration
2) wet/gas - necrosis then colonisation by bacteria –> liquefaction and putrefaction

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49
Q

What are differences between liquefactive and caseous necrosis?

A

liquefactive - from rapid degradation of cells and accumulation of neutrophils = pus
Caseous - dry debris +/- mineralisation often with rim of inflammation or fibrous tissue capsule

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50
Q

What are some causes of fat necrosis?

A
  • lipolytic enzymes from necrotic exocrine pancreas
  • trauma
  • ROS damage as deficient in Vit. E and selenium
  • hypoxia
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51
Q

What is dystrophic mineralisation?

A

Accumulation of calcium salts in tissues with oncotic necrosis = gritty, hard, chalky foci

intracel - accum of Ca2+ in mitochondria of dead cells
extracell = ca2+ to membrane phosphates of disintegrating cells = mycrocrystal formation

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52
Q

Give an example of an environmental signal

A

light = change in rhodopsin (photoreceptive protein) -> activates transducin -> cGMP lowered

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53
Q

What is the function of a tropic hormone?

A

to regulate hormone production of another cell

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54
Q

Where is the pituitary gland located and how is it divided?

A

it is in the sella truck, connected to the hypothalamus by the sella turcica. Divided into anterior and posterior pituitary.

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55
Q

which pituitary portion receives portal venous inflow? What does this breach?

A

Only the anterior pituitary - breaches BBB

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56
Q

Where does the hypophyseal artery enter?

A

In the primary capillary plexus - in lower hypothalamus, takes up inhabit or releasing hormones –> portal system to secondary capillary plexus

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57
Q

What are the factors influencing release of Growth Hormone?

A

Growth hormone releasing hormone
Somatostatin (inhibits)
Ghrelin (peptide hormone from stomach, stimulates)
stress, exercise, nutrition, sleep, GH itself

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58
Q

What is ACTH and what does it do once in the bloodstream?

A

Adrenocorticotrophic hormone
To adrenal cortex = glucocorticoid release (cortisol, adrenal androgens)
Influenced by stress, circadian rhythms, feedback

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59
Q

What is the half life of a peptide hormone like?

A

short as unbound to plasma protein

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60
Q

What to thyroid hormones and catecholamines have in common? How are they different?

A

Both amino derived
Thyroid - lipid soluble = intracel. target
Catecholamins - hydrophilic - alpha and beta surface receptors

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61
Q

What inhibits prolactin release?

A

Dopamine from hypothalamus - if stalk cut = no dopamine, so prolactin levels rise.

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62
Q

What does low affinity mean in terms of the number or receptors to ligands?

A

High conc. of receptors to ligands

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63
Q

What is meant by a molecular switch?

A

It means activation/inactivation by binding of molecules

  • activation by phosphorilation
  • guanine nucleotide to G protein
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64
Q

What are the 6 steps to signal transduction?

A

1) recognition of signal
2) transduction (extracell. message to intracell)
3) transmission of second messengers
4) modulation of an effector (altering enzyme activity)
5) appropriate response
6) termination of response

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65
Q

Explain the activation of a G protein coupled pathway acting via adenylate cyclase (Gi/Gs)

A

ligand binds = conformational change of receptor. The Ga subunit binds to G protein and releases GDP, binds GTP. Gy and Gb components dissociate. G protein active until GTP is hydrolysed.
Active G protein activates adenylate cyclase allowing ATP –> cAMP
cAMP = secondary messenger: activates PKA to activate other certain enzymes

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66
Q

How to adrenaline and prostaglandin act antagonistically in terms of G proteins?

A

Both act on adenylate cyclase
adrenaline activates it
prostaglandin inhibits it
They bind to two different G proteins (Gi and Gs) but have the same second messenger.

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67
Q

How does cholera toxin act with G proteins?

A

The bacterium secretes a toxin that can form a very similar activator to adenylate cyclase as G protein. Decays much slower so pathway not turned off.
In gut adrenaline to G protein receptor - adenylate cyclase activation = H2O and chloride secretion (with cholera this continues) = diarrhoea and dehydration

Give adrenaline antagonist

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68
Q

What type of G proteins act via phospholipase C? What are the second messengers?

A

Gq proteins
Activation of phospholipase C = activation of IP3 and DAG
IP3 = intracell Ca2+ release
Ca2+ + DAG = protein kinase C activatiom

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69
Q

How are calmodulin and protein kinase C linked?

A

Protein kinase C subunit = calmodulin

if binds with Ca2+ = more catalytic efficiency/accelerating protein

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70
Q

Can the Gyb subunit have a role?

A

Yes - while parasymp. ACh at the heart causes Gi protein activation, Gyb goes on to open K+ channels aiding in depolarisation - slowing of heart

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71
Q

Explain the role of G proteins and NO signalling to increase blood flow

A

ACh/bradykinin/adenine nucleotides –> Gq at vascular endothelial cell –> IP3 –> Ca2+ and calmodulin
Ca2+ and calmodulin activate NO synthase = NO production
NO out od endothelial cell –> adjacent smooth muscle and activates guanylyl ciclase –> cGMP = phosporylation of muscle proteins = relaxation = vasodilation and increased blood flow

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72
Q

What is the difference between a receptor tyrosine kinase and a tyrosine kinase linked receptor?

A
  • receptor tyrosine kinase: receptors themselves are protein kinases - cross-phosporilate with dimerisation then phosphorylate tyrosine residues on intracell. enzymes/proteins
  • tyrosine kinase linked receptor: don’t have intrinsic enzyme activ bind/dimerise first then bind cytoplasmic tyrosine kinase -> phosphorylate target proteins
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73
Q

What is meant by the term desensitisation?

A

if a particular signal persists, the threshold to elicit transduction increases - down regulate receptors, alter receptor (lower affinity) or make it unable to initiate changes in cellular function

74
Q

How does skeletal muscle move bone?

A

Through muscle tendon complex

muscle contraction = pulling on tendon = pulling on bone

75
Q

What do muscle spindles allow perception of?

A

Stretch = sensory nerve stimulation = perception of position, velocity and acceleration of contraction

76
Q

what is the role of the fascia adherens?

A

To anchor actin to nearest sarcomere (cardiac muscle)

77
Q

What determines the size of the cell body of a neuron?

A

the level of activity and length of processes it has to support

78
Q

Why would we want to reduce astrocyte activity with spinal chord injury?

A

They are the scar forming cells = block reinervation

79
Q

What is a satellite cell?

A

Glial cell covering ganglion cells, thought to have similar role to astrocytes in CNS

80
Q

Why will the resting membrane potential not decrease to equilibrium potential of potassium?
How is this RMP maintained?

A

Even though more permeable to K+ (dif. out of cell), sodium will diffuse into the cell down conc. gradient
these gradients are maintained by Na+/K+ ATPase (2K+ in, 3Na+ out)

81
Q

What is the absolute refractory period?

A

Period after action potential where Na+ permeability changes

82
Q

What determines the velocity of an action potential?

A

diameter of axon and myelination of neuron

83
Q

Why is the location of the synapse also of importance for the outcome (action potential or not)

A

The postsynaptic cell body has resting membrane potential much closer to threshold
spacial summation can also occur

84
Q

What does binding of ACh at nicotinic receptor on skeletal muscle do?

A

Sodium channel opening = depolarisation

85
Q

How is the number of fibres in a motor unit related to fine control of muscle?

A

If less fibres controlled by motor unit = finer control

86
Q

What is the release of ACh from neuron dependent on?

A

Action potential –> calcium influx presynaptically allowing fusion of vesicles

87
Q

What is the role of calcium in skeletal muscle contraction?

A

It is released from the sarcoplasmic reticulum by depolarisation (Na+ influx) - then bins to troponin = shift of tropomyosin = actin myosin binding.
Need Ca2+ removal back into sarcoplasmic reticulum to stop contraction (Ca2+ ATPase)

88
Q

What has to happen for muscle to relax?

A

Ca2+ must be moved out of cytoplasm and action potential has to be stopped (ACh degradation)

89
Q

What are the three roles of ATP

A

1) energy for power stroke
2) breaking of cross bridge (binds to myosin)
3) drives Ca2+ ATPase pump

90
Q

When are more motor units recruited?

A

In increased intensity of stimulation - recruit more motor units until all activated

91
Q

What are the three cells found in heart muscle?

A

myocardial cells, pacemaker and parking fibres

92
Q

Does smooth muscle have t-tubules and a sarcoplasmic reticulum?

A

No they have calveoli (membrane invaginations) - sarcoplasmic reticulum only if rudimentary, have very low stores of intracell. Ca2+

93
Q

Where is multiunit smooth muscle found?

A

large airways of lungs, ciliary muscle of eye

94
Q

What role does calcium play in smooth muscle contraction?

A

Mostly extracell calcium, in through ligand gated ion channel. Binds to calmodulin in cytoplasm
Ca-clamodulin -> myosin light chain kinase active –> phosphorylation of myosin cross bridges = binding with actin filaments

95
Q

What is the difference between Golgi tendon organs and muscle spindles?

A

Golgi: in tendons, reports tension and force of muscle contraction
Muscle spindles: in muscle, report stretch

96
Q

What does the muscle spindle detect?

A

rates of change in stretching of muscle and changes in length of muscle - constant feedback and minute adjustments

97
Q

What are motor neurons are intrafusal and extrafusal fibres supplies by?

A

Intrafusal: gamma motor neuron
Extrafusal: alpha motor neuron
normally coactivation of both

98
Q

Describe the stretch reflex and reciprocal innervation

A

muscle spindle detects stretch –> synapses with alpha motor neurone in spinal chord –> contraction of muscle that was stretched

reciprocal innervation: in spinal chord synapses with inhibitory interneuron –> relaxation of antagonistic muscle

99
Q

In stretch reflex and Golgi tendon response - is the brain made aware of what has happened?

A

yes but often after response has occurred, from spinal chord - signal to brain for appraisal of change

100
Q

Describe the tendon reflex

A

contraction of muscle –> synapses with inhibitory interneuron –> motor nerve to relax contracted muscle

reciprocal innervation: excitatory interneuron at spinal chord –> motor nerve –> contraction of antagonistic muscle

101
Q

What is the EC50 a measure off?

A

the potency of a drug, how much to give

102
Q

What is Vd?

A

Volume of distribution = X/C, where X is drug administered and C is concentration measured after administration.
shows us extent of distribution but not location. To determine initial dose.

103
Q

What is Clearance?

A

The irreversible removal of drugs by excretion or metabolism

104
Q

What can t1/2 be used for?

A

To determine dosing interval

105
Q

What neurotransmitter is found in the ganglia of the autonomous nervous system?

A

ACh binding to nicotinic receptors

106
Q

What neurotransmitter is used at the target for parasympathetic postganglionic neurons? and what receptor?

A

ACh to Muscarinic receptor

107
Q

What kind of muscarinic receptors are there and where are they found?

A

M2: cardiac, Gi = inhibitory by opening K+ channels, decrease heart rate
M3: smooth muscle/glandular, Gq = stimulatory, IP3 = increase in Ca2+ increase contraction of GIT and secretion

108
Q

What type of receptor do sweat glands have? Are they parasympathetic or sympathetic? What is the postganglionic neurotrans?

A

Muscarinic, Sympathetic, bound by ACh

109
Q

What are the different types of adrenoceptors?

A

a1 - smooth muscle contraction
a2 - inhibitory, pre junctional, contraction of smooth muscle
b1 - heart, increase in contractility
b2 - airways, dilation of muscle/blood flow
b3 - fat - lipolysis

110
Q

How is Adrenaline synthesised

A

From tyrosine
tyrosine –> (into cell) L-Dopa –> Dopamine –> (into synaptic vesicle) NA –> Adr (into blood - stimulation of release by sympathetic NS)

111
Q

What do the adrenal glands secrete

A

Adr, NA, Aldosterone

112
Q

Is NA found in the blood?

A

No - mainly neurotransmitter at postganglionic parasymp. nerves

113
Q

How can NA action be increased?

A

Decreasing reuptake of presynaptic neutron with drugs
- cocaine
- desipramine
By stimulating non exocytotic release (not calcium dependent) with sympathomimetics
- amphetamine
- Epinephrine

114
Q

Name a selective agonist and antagonist of alpha 1 and their effects. (a1pp)

A

Agonists: phenylephrine –> constriction of blood vessels.
Increases BP, decongests, reflex bradycardia = decreased heart rate

Antagonists: Prazosin –> dilation of blood vessels
Decreases BP

115
Q

Name a selective agonist and antagonist of alpha 2 and their effects. (a2cy)

A

Agonist: clonidine –> decrease peripheral vascular resistance = decrease BP

Antagonist: yohimbine –> at low doses causes increase in BP

116
Q

Name a selective agonist and antagonist of beta 1 and their effects. (b1da)

A

Agonist: Dobutamine –> (treat heart failure) - increases contractility and cardiac output

Antagonist: Atenolol –> decreases heart rate and workload (treat hypertension)

117
Q

Name a selective agonist and antagonist of beta 2 and their effects.

A

Agonist: Salbutamol –> relaxation of smooth muscle

118
Q

How is ACh synthesised?

A

Choline –> (into cell) binds with acetyl (from acetyl CoA) –> ACh –> into vesicle

119
Q

What are the actions of muscarinic receptors?

A

SLUD, sweating, slowing of heart, bronchoconstriction, vasodilation

120
Q

Name agonists of muscurinic receptors

A

pilocarpine
carbachol (in GIT and bladder paralysis)
bethanecol (obstruction)

121
Q

What are methods to increase ACh action?

A

Anticholinesterases (drugs)

  • physiostigmine
  • neostigmine (more active at NMJ) - use for myasthenia gravis (more ACh for decreased number of receptors) and can reverse blockage by tubocurarine)
122
Q

How can release of ACh be modulated?

A
  • need calcium for exocytosis

- drug: Botulinum toxin used to cleave snare proteins = cannot bind vesicles

123
Q

Name to muscarinic antagonists and when you would use them

A

Atropine: antiSLUD: can increase heart rate - but if very fit and parasymp. NS dominates heart muscle tone - will cause tachycardia. Reduces secretions.

Hyoscine: motion sickness

124
Q

What does physostigmine do?

A

is an anti cholinesterase - increases ACh action

125
Q

What does neostigmine do? Where does it act?

A

is an anti cholinesterase - more active at NMJ

126
Q

What is a H1 receptor antagonist known as? What are they used for?

A

Antihistamines

For hayfever, anaphylaxis, atopic dermatitis

127
Q

How can peptic ulcers be treated?

A

H2 receptor antagonist (cimetidine, ramitidine)

Block receptor on parietal cell for Histamine = decrease acid production

128
Q

What is Bradykinin? What does it do?

A

local peptide released with plasma exudation

Action: increases vascular permeability = inflam. and stimulates sensory nerve endings = pain

129
Q

What are prostanoids?

A

All from arachidonic acid and COX pathway

prostglandins and prostacyclins

130
Q

Are eicosanoids stored?

A

No produced on demand

131
Q

What do leukotrienes cause?

A
  • chemoattractant

- constriction of bronchi

132
Q

What are the actions of PG’s?

A

vasodilation and pain (PGI), mast cell degranulation (PGD), platelet aggregation (TXA), fever and pain (PGE)

133
Q

How is blocking the COX pathway beneficial? What blocks this?

A
  • NSAIDs block - no PGE2 = no pain, no fever = enhanced clinical benefits - but also decreased mucous production
  • Glucocorticoids (also at many other levels)
134
Q

What are the four decisions an embryogenic cell must make

A

1) division to increase in number
2) differentiate
3) cell morphology change
4) apoptosis

135
Q

What are the three broad periods of gestation?

A

ovum
embryo
foetus

136
Q

What is a morula? What does this turn into?

A

Morula = ball of cells

–> Blastomere = beginning of differentiation, loose spherical shape

137
Q

What is gastrolation broadly?

A

Formation of three germ layers

- ectoderm, mesoderm and endoderm

138
Q

What is cleavage?

A

Division of cells without increasing in volume (hyperplasia)

139
Q

What is a blastocyst?

A

3 layers:
embryonic disc: inner cell mass
trophoblast cells: absorb nutrient (and enzymes that degraded the zone pellucida)
cavity: blastocoele

140
Q

What is the chorion?

A

extra-embryonic membrane
trophoectoderm and mesoderm derived
attach to uterus, sac around everything

141
Q

How does gastrulation progress?

A

thickening of the embryonic disk and delamination –> two layers. Trophoblast, amnionic cavity and bilaminar embryonic dic. with inner epiblast and outer hypoblast.

Formation of primitive streak - head and tail/axis. epiblast and hypoblast separate. Epiblast through streak –> endoderm and mesoderm. Hypoblast week replaced by endoderm.

Mesoderm splits into two layers: coelum
somatic mesoderm - attached to ectoderm
splanchnic mesoderm - attached to endoderm

142
Q

What is the yolk sac?

A

extra-embryonic membrane
primitive endoderm derived,
regresses with time

143
Q

What is the allantois?

A

extra-embryonic membrane
primitive gut derived
collects waste from embryo and fuses with chorion –> foetal contribution to placenta

144
Q

What is the allantois?

A

extra-embryonic membrane
primitive gut derived
collects waste from embryo and fuses with chorion –> foetal contribution to placenta

145
Q

What is the notochord?

A

A rod shaped aggregation of cells cranial to primitive streak in mesoderm.
Marks location for future spinal chord.
Directs procesesses (head formation)

146
Q

What is neurolation?

A

Initial development of gut, heart and formation of NS

147
Q

How is the neural tube formed?

A

Thickening of ectoderm over notochord forming neural plate. Elevation = neural folds converge at midline.

148
Q

What are neural crest cells?

A

Cells at the lateral margins of the neural tube - go on to form other structures

149
Q

What are somites? And what are the tissues called moving laterally?

A

Balls of mesoderm tissue that form spine and limb buds. Can be used for waging.

tissue closest to neural tube/paraxial mesoderme = somite –> intermediate mesoderm (urinary and reproductive system) –> lateral mesoderm (somatic and splanchnic - forming cavities)

150
Q

What occurs following gastrulation?

A

The embryo becomes C shaped

  • surface ectoderm invaginate = pharyngeal clefts
  • internal endoderm evaginates = pharyngeal pouches
  • cardiac bulge
  • limb buds
151
Q

What is the difference between aplasia and hypoplasia

A

None really can be used interchangeable

= failure to grow

152
Q

Why would a cell change in structure and function?

A

To adapt to physiological stress or adverse stimuli - to find a new steady state and survive

153
Q

What are some causes of atrophy?

A
decreased workload
loss of innervation
decreased blood supply
loss of endocrine stimulation
obstruction of secretory ducts
inadequate nutrition 
ageing
154
Q

What is serous atrophy of fat?

A

In emaciated animals - rapid mobilisation of fat stores = gelatinous, pale pink transformation
If very advanced - serous atrophy of bone marrow

155
Q

What is serous atrophy of fat?

A

In emaciated animals - rapid mobilisation of fat stores = gelatinous, pale pink transformation
If very advanced - serous atrophy of bone marrow

156
Q

How can small intestinal villous atrophy occur? What clinical signs might you see?

A
  • loss of enterocytes from villi
  • necrosis/imparied mitosis of crypt stem cells
  • dysregulation of crypt stem cell proliferation and enterocyte maturation

Clinical signs: diarrhoea (decreases SA, osmotic drag)

157
Q

What is abiotrophy?

A

Genetically programmed premature or accelerated degeneration of mature cells

158
Q

What is meant by replicative senescence? What enzyme can prevent this and where is it present?

A

Cells have a fixed number of divisions determined by the length of their telomeres.

Telomerase can extend these, found in tumour cells

159
Q

What are senile cataract and how are they related to ageing?

A

Accumulation of abnormally folded protein causing blindness

Protease function declines with age = persistence of these proteins.

160
Q

Is it grossly possible to distinguish between hypertrophy and hyperplasia?

A

No - need a microscope

161
Q

In what tissues can hyperplasia occur?

A

Only in those capable to mitotically divide

162
Q

How is hyperplasia different to neoplasia

A
  • responds to stimuli

- excess cells will be deleted by apoptosis

163
Q

What is metaplasia? Why would this occur?

A

It is the transformation (better: replacement) of a fully mature cell type into another mature cell type - through mitotic division.
Often occurs in order to form more resistant cell type in exchange for specialised function

164
Q

Where can metaplasia be seen?

A
  • with chronic irritation of epithelium/mucosa i.e. urinary tract with uroliths: epithelium may become stratified squamous
  • with chronic irritation - can get mucus secreting cells in fundic mucosa (decrease HCL secretion = decrease digestion)
165
Q

What is cellular pleomorphism?

A

Lack of uniformity - variation in cell and nuclear size, shape and appearance.
Seen with dysplasia

166
Q

What is Stroma?

Is it neoplastic?

A

The connective tissue supporting neoplastic cells.

Not neoplastic, will not grow without neoplastic cells.

167
Q

What are the four means to distinguish between benign and malignant neoplasia?

A

1) invasion into adjacent tissue
2) metastasis
3) degree of differentiation
4) growth rate

168
Q

What are the three pathways of metastasis?

A

1) haematogenous (favoured by sarcoma)
2) lymphatic (favoured by carcinoma)
3) implantation

169
Q

What would you call a benign epithelial neoplasm:

  • that is glandular
  • that is non-glandular
A

glandular: –adenoma

non-glandular: –papilloma

170
Q

What would you call a malignant epithelial neoplasm:

  • that is glandular
  • that is non-glandular
A

glandular: –adenocarcinoma

non-glandular: carcinoma

171
Q

What is the difference in naming: –oma vs. –sarcoma?

A

Both mesenchymal neoplasms.

  • -oma: benign
  • -sarcoma: malignant
172
Q

What is a teratoma?

A

Neoplasm with cells of more than one germ layer (multipotent cells, testes and ovaries) - have well differentiated tissue - bone, teeth

173
Q

What is a choristoma?

A

Malformation, normal cells at abnormal location. Not neoplastic

174
Q

What is meant by paraneoplastic syndrome? Give examples

A

Diseases seen with neoplasm but not directly caused by neoplasm

  • pyrexia (pro-inflam. cytokine in response to neoplasm)
  • autoimmune response (antigen expressed in tumour cells, can cause cross reactive antibodies with host as v similar morphology –> immune mediated haemolytic anaemia)
  • hormone secretion (parathyroid related hormone stimulating bone resorption to increase blood Ca2+)
175
Q

What are the 4 normal regulatory genes of growth/division?

A

1) proto-oncogenes
2) tumour supressor genes
3) genes involved in DNA repair
4) genes regulating apoptosis

176
Q

What are the 8 Hallmarks of Neoplasia?

A

1) No need for growth signals/produce own
2) No response to growth inhib signals
3) No apoptosis
4) Have telomerase = immortality
5) Angiogenesis - can vascularise themselves
6) can survive with glycolysis always
7) Avoid immune response
8) Can invade and metastasise

177
Q

What are the three categories of chemical carcinogens?

A

1) initiators - direct DNA damage
2) promoters - increase proliferation of mutated cells, increase chance of survival;
3) complete - initiate and promote (ionizing radiation)

178
Q

How do viruses cause cancer? Give some examples.

A
  • altering expression of normal regulatory genes
  • introducing virally encoded homologues of proto-oncogenes
  • inducing chronic inflam = oxidative DNA damage

e.g. retroviridae = feline leukaemia virus

179
Q

What bacterium is neoplasia causing?

A

H. pylori –> gastric adenocarcinoma and lymphoma

180
Q

What is tubocurarine?

A

Nicotinic recpetor antagonists = skeletal muscle relaxant. Can still get contraction with direct stimulation. Reversible.

181
Q

What is tetrodotoxin?

A

Voltage operated Na+ channel blocker

182
Q

What is Suxamethonium and what happens if ACh is increased in the synapse? Or if directly stimulated?

A

Nicotinic receptor agonist - constant depolarisation = unable to contract,
even if increase in ACh (neostigmine) as sodium channels are open = constant depolarisation.
Direct stimulation would not cause contraction either.