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Acem Primary > Pathology and Physiology > Flashcards

Pathology and Physiology Flashcards

1
Q

In the bladder, the first urge to void is felt at, and a marked sense of fullness is at ?

A

150mls and 400mls

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2
Q

What is permeable in the thin descending portion of the loop of Henle?

A

Highly permeable to H2O and only slightly permeable to NACL
Due to the presence of aquaporin-1 in both the apical and basolateral membrane

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3
Q

What is permeable in the thin ascending portion of the loop of Henle

A

Not permeable to H2O
Highly permeable to NaCl

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4
Q

What is permeable in the thick ascending portion of the loop of Henle

A

Not permeable to H2O
Only slightly permeable to NaCl

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5
Q

What is permeable in the collecting tubules of the kidneys?

A

highly permeable to water in the presence of vasopressin

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6
Q

How is sodium transported in the renal tubule

A

Actively transported out of all parts of the renal tubule except the thin portions of the loop of Henle

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7
Q

Filtration fraction of Kidney is?

A

0.16-0.20

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8
Q

Explain the control of the external urethral sphincter

A

Controlled by the pudendal nerves which are somatic
Contraction of the perineal muscles and external sphincter can be contracted voluntarily, preventing urine from passing down the urethra or interrupting flow once urination has begun

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9
Q

What happens to the kidneys during a fall in systemic blood pressure?

A

Renal plasma flow decreases more than eGFR
Filtration fraction increases
Both afferent and efferent arterioles are constricted, efferents to a greater degree
Sodium retention is marked
Nitrogenous products of metabolism are retained in the blood giving rise to azotaemia and uraemia
Prolonged can cause renal tubular damage and acute renal failure

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10
Q

Osmolality of the pyramidal papilla

A

1200mosm/kg

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11
Q

What is the best substance to measure eGFR?

A

Eg, Inulin
a substance that is freely filtered, niether reabsorbed nor secreted, is nontoxic and not metabolised by the body

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12
Q

Proximal convoluted tubule reabsorbs how much filtered sodium ?

A

60%

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13
Q

How does sodium move through the nephron?

A

PCT reabsorbs 60% of filtered sodium
It is pumped back into the interstitium by the Na/K/ATPase
It does share a common carrier with glucose
30% is absorbed via the Na/2Cl/K cotransporter in the thick ascending limb of the loop of Henle
7% via the NaCL contransporter in the DCT
3% via the ENaC channels in the collecting duct

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14
Q

In osmotic diuresis what causes increased urine flow?

A

Decreased water reabsorption in the PCTs and loop of Henle

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15
Q

Renal acid secretion is altered by?

A

Changes in the intracellular pCO2
Potassium concentration
Carbonic anhydrase level
adrenocorticol hormone concentration including aldosterone

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16
Q

Describe glucose absorption in the kidneys?

A

Glucose reabsorption is an active process
Closely associated with sodium
Occurs predominantly in the proximal convoluted tubule
Sodium Glucose Linked Transporters actively reabsorb glucose (SGLT)
excreted in urine if renal threshold is exceeded

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17
Q

Urea in the kidneys

A

Passively crosses biological membranes, permeability is low because of its low solubility in lipid bilayer
Urea transporters (4) move urea by facilitated diffusion out of the proximal tubule.
Urea plays a role in the establishment of an osmotic gradient in the medullary pyramids.
Increases the ability of the kidney to concentrate urine in the collecting ducts .

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18
Q

Where in the kidney is the tubular fluid isotonic?

A

Proximal convoluted tubule
In the PCT water moves passively out of the tubule along the osmotic gradient.

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19
Q

Conditions that increase renin secretion

A

Sodium depletion, diuretics, hypotension, haemorrhage, upright posture, dehydration, cardiac failure, cirrhosis, constriction of renal artery or aorta

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20
Q

Factors that inhibit renin secretion

A

Increased Na and Cl reabsorption across macula densa
Increased afferent arteriolar pressure
Angiotensin II
Vasopressin

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21
Q

Describe the cells that make up the proximal convoluted tubule?

A

Made up of a single layer of cells that interdigitate with one another and are united by apical tight junctions
Luminal edges of the cells had a striate brush border due to microvilli

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22
Q

Describe the renal handling of potassium?

A

Potassium (K) is actively reabsorbed in the proximal convoluted tubule
K is secreted in the distal tubular cells
In the collecting ducts K is secreted
The rate of K secretion is proportionate to the rate of flow of the tubular fluid through the distal portions of the nephron, because with rapid flow there is less opportunity for the tubular K concentration to rise to a value that stops further secretion

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23
Q

Describe Vasopressin

A

AKA Antidiuretic Hormone
Increases the permeability of the collecting ducts so that water enters the hypertonic interstitium of the renal pyramids.
urine becomes concentrated and volume decreases.
standing increases vasopression secretion
There are 3 vasopressin receptos V1a, V1b, V2

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24
Q

Describe the Proximal Convoluted Tubule

A

15mm long
55um in diameter
wall is made up of single cell layer, united by tight apical junctions.
Luminal edges have a brush border due to microvilli
Found in the cortex of the kidney

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25
Q

Action of aldosterone on the kidneys

A

Promotes sodium reabsorption and potassium secretion

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26
Q

6 ways aldosterone promotes Na and water retention and lowers K conc

A
  1. Acting on the distal tubule and collecting duct of the kidney nephron, it activates the basolateral Na/K pumps, which pumps three sodium ions out of the cell and two potassium ions into the cell.
  2. Aldosterone upregulates epithelial sodium channels increasing apical membrane permeability for Na+.
  3. Chloride is reabsorbed in conjunction with sodium cations to maintain the system’s electrochemical balance.
  4. Aldosterone stimulates the secretion of K+ into the tubular lumen
  5. Aldosterone stimulates Na+ and water reabsorption from the gut, salivary and sweat glands in exchange for K+.
  6. Aldosterone stimulates secretion of H+ in exchange for Na+ in the intercalated cells of the cortical collecting tubules regulating plasma bicarbonate levels and acid/base balance
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27
Q

Neurological pathways involved in normal micturition

A

Sacral spinal reflex mediated by S2 S3 and S4 nerve roots
First urge to void at 150mls, marked fullness at 400mls
Micturition reflex
Sympathetic nerves to the bladder play no role in micturition

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28
Q

What is the micturition reflex?

A

Stretch receptor in the bladder wall
Afferent limb in pelvic nerves
parasympathetic efferent fibres, via same pelvic nerves, mediate contraction of detrusor muscle.
Pudendal nerve S2 S3 S4 permits voluntary contraction of perineal muscles/external urethral sphincter to slow or halt flow

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29
Q

Describe the muscles involved in micturition

A

Bladder; smooth muscle arranged in spiral, longitudinal and circular bundles
Circular bundle is called the detrusor muscle, contraction is responsible for involuntary emptying
External urethral sphincter; skeletal muscle, relaxes during micturition, voluntary controlled
Perineal muscles, relax during micturition, voluntarily controlled.
Contraction of abdomen aids expulsion of urine.

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30
Q

Factors that stimulate micturition

A

Stretch/pressure
Higher centre input
Parasympathetics
sympathetic inhibiting drugs

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31
Q

Inhibitors of micturition

A

Parasympathetic inhibitors
Higher centres
Sympathomimetics

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32
Q

Consequences of glycosuria

A

Osmotic diuresis
dehydration
electrolyte loss

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33
Q

Where does sodium reabsorption occur in the nephron?

A

Filtered by the glomerulus, 99% reabsorbed overall
60% reabsorbed in the PCT by the Na/H exchange and a range of cotransportes with gluose
30% thick ascending limb of the loop of henle
7% DCT via NaCl cotransporter
3% via ENaC channels in the collecting ducts

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34
Q

With high Na intake, what mechanisms enhance Na excretions

A

Stretch receptors in pulmonary veins inhibit sympathetic outflow of the kidneys and decreased Na absorption
Small increase in arterial pressure can cause pressure natiuresis
Suppression of ATII formation, reducing aldosterone activity
Stimulation of ANP

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35
Q

How does the kidney reduce na secretion

A

Reducing eGFR to reduce the amount filtered
Increasing tubular reabsorption via increase in adrenocorticol hormones such as aldosterone

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36
Q

How does aldosterone influence sodium handling?

A

Aldosterone acts on principal cells in collecting ducts to increase the number of active epithelial sodium channls
Upregulates and activated basolateral Na/K ATPase
Increased tubular reabsorption of Na and Cl follows
Secretion of K into lumen via exchange with Na
Latent period of 10-30 minutes before the effect

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37
Q

Microscopic changes in Malignant Hypertension

A

Intimal thickening caused by concentric proliferation of smooth muscle cells and collagen which accumulates in a layered configuration (together with accumulation of proteoglycans and plasma proteins).
This gives an onion skinning appearance.
This lesion is also called hyperplastic arteriolitis and correlates with renal failure in malignant hypertension

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38
Q

Describe post infections glomerulonephritis

A

Acute glomerulonephritis occurs most frequently in children aged 6-10yrs, 1-4 weeks after a streptococcal infection of the pharynx or skin (impetigo). It is due to a group A beta haemolytic streptococcus

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39
Q

Manifestations of nephrotic syndrome

A

massive proteinuria, hypoalbuminaemia, generalised oedema (increased interstitial fluid), hyperlipidaemia and lipiduria

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40
Q

Causes of nephrotoxic acute tubular necrosis

A

Gentamicin
Radiographic contrast agents
Heavy metal poisoning
Organic solvents

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41
Q

Most common cause of acute renal failure

A

Acute tubular necrosis in 50%

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42
Q

Describe ischaemic acute tubular necrosis (ATN)

A

Associated with focal tubular epithelial necrosis.
There is rupture of the basement membrane and occlusion of tubular lumen by casts.
Lesions occur in a skip like pattern along the nephron.
The straight portion of the proximal tubule (PST) and the ascending thick limb in the renal medulla are especially vulnerable.

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43
Q

What are the extra renal congenital abnormalities in polycystic kidney disease

A

40% have polycystic liver disease. Intracranial berry aneurysms arise in the circle of Willis and Sub-arachnoid Haemorrhage (SAH) account for 4-10% of individuals.
Mitral valve prolapse and other cardiac valvular anomalies occur in 20-25%. Ultimately about 40% of adult patients die of coronary or hypertensive heart disease, 25% of infection, 15% of ruptured berry aneurysms or hypertensive intracerebral bleed.

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44
Q

What is the most common cause of chronic pyelonephritis?

A

Chronic vesicoureteral reflux

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45
Q

How does the kidney deal with potassium

A

Freely filtered at the glomerulus 600mmol/day
Actively reabsorbed in the PCT over 90%
Also reabsorbed in the Na/K/2Cl co transporter
Secreted in the DCT - rate proportional to flow
Secreted in the CD in response to aldosterone

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46
Q

Where in the renal tubules does the intratubular and interstitial osmolality hold the same values?

A

Thin descending loop of Henle

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46
Q

Where does acidification of the urine occur

A

Proximal and distal tubules and collecting ducts

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47
Q

How is H+ secreted in the PCT and the DCT/CD?

A

PCT: Na/H exchange transporter, this pathway also involves the action of carbonic anhydrase which allows the recycling of H+ and absorption of 1Na and 1HCO3 for every H+ secreted
DCT/CD: secretion of H+ is independent of Na. ATP driven pump, also H/K/ATPase pump and anion exchanger

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48
Q

What is the limiting pH and where does it occur

A

pH is 4.5
Occurs in the collecting duct

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49
Q

In metabolic acidosis describe the buffer systems

A

Bicarbonate - HCO3 forms CO2 and H2O
Phosphate - HPO4 forms H2PO4
Ammonia - NH3 to NH4

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50
Q

What happens to glutamine synthesis in chronic metabolic acidosis

A

Glutamine synthesis increased in the liver
Provide the kidneys with enough ammonia to form a buffer

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51
Q

How do the kidneys deal with potassium ?

A

Freely filtered at the glomerulus 600mmol/day
Actively reabsorbed in the PCT
Reabsorbed in the NaK2Cl co transporter
Secreted in the DCT
Secreted in the CD in response to aldosterone

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52
Q

Explain potassium transport in the collecting duct

A

The H-K ATPase in the cells of the collecting ducts reabsorbs K in exchange for H

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53
Q

What is the role of urea in the countercurrent mechanism

A

Contributes to the osmotic gradient in the medullary pyramids
Enhances the ability of the kidney to concentrate urine

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54
Q

How does the kidney handle urea?

A

Facilitated diffusion out of the late PCT
Secreted in the loop of henle
Reabsorbed in the collecting ducts
40% of filtered urea can be found in urine
The amount of urea depends on the amount filtered which is influenced by dietary protein

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55
Q

How does urea reach the interstitium ?

A

Facilitated diffusion
Transported via 4 different urea transporters

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56
Q

What is normal renal blood flow?

A

1.2-1.3L per minute or 25% of cardiac output

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57
Q

What factors determine renal blood flow?

A

Precision pressure (systemic MAP)
Renal artery effects - local constriction from Na, Ang II, dilation from ACh, PGs, dopamine, renal nerves, auto regulation, regional differences between cortex and medulla

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58
Q

How can renal blood flow be measured

A
  1. Fick principle - amount of a substance taken up per unit time divided by arterio-venous concentration difference
  2. Para-amino hippuric acid (PAH) - excreted 90% cleared
    ERPF = clearance of PAH = UV/P = 630ml/min
    U = urine concentration
    V = volume of urine collected in minutes
    P = plasma concentration
  3. Acute renal plasma flow = ERPF/0.9 = 700ml/min
  4. Renal blood flow (including RBC) so it’s
    Acute renal plasma flow / 1-HCT = 1250ml/min
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59
Q

How do blood flow and oxygen extraction vary in different parts of the kidney?

A

Cortical flow is high and oxygen extraction is low
Medullary blood flow is low and oxygen extraction is high because there is a lot of metabolic work done
Medulla is more vulnerable to hypoxia damage

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60
Q

What is a normal GFR

A

125ml/minute or 180L in 24 hours

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61
Q

How does thirst restore fluid status?

A

As plasma oncotic pressure rises it is sensed by the osmoreceptors in the anterior hypothalamus
Triggers a release of vasopressin from the posterior pituitary
Vasopressin acts on the V2 receptor to trigger insertion of aquaporin channels into the luminal membrane of the renal collecting tubules. Aquaporins are usually stored in the cytoplasm of principal cells. Insertion of these allows more water to return to the body

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62
Q

How does hypotension activate the RAAS system

A

Hypotension leads to reduced perfusion pressure of the afferent glomerular arteriole
Stimulating release of renin by the juxtaglomerular cells
Renin converts angiotensinogen to angiotensin I
Angiotensin converting enzyme converts angiotensin I to II
Angiotensin II acts on the adrenal cortex’s zona glomerulosa cells to release aldosterone
This acts on the renal distal tubules to retain Na+ and water thus increase intravascular volume
Angiotensin II is also a potent arteriolar constrictor

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63
Q

Physiological factors are involved in regulating renin secretion

A

Intrarenal baroreceptors - an increase in afferent arteriolar pressure in JG cells causing a decrease in renin secretion
Increased resorption of Na and Cl in the distal tubules in the macula densa causes a decrease in renin secretion
Increase in sympathetic nervous system stimulates renin
Vasopressin can decrease renin
Angiotensin II provides inhibitory feedback to JG cells

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64
Q

What is the main inhibitory neurotransmitter of the spinal cord?

A

Glycine
It is also the responsible for direct inhibition in the brainstem

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65
Q

What is the main inhibitory neurotransmitter in the brain?

A

GABA

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66
Q

Describe the vestibulocochlear nerve?

A

CNVII
special senses for hearing, equilibrium and motion
originate in the grooves of the pons and medulla
run through the internal acoustic meatus
vestibular nucleus arises in the pons

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67
Q

Where is visual acuity the greatest?

A

Fovea centralis

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68
Q

Principal hypothalamic regulatory mechanisms?

A

Temperature regulation
Neuroendocrine control
‘Appetite’ behaviour - thirst hunger sexual
Defensive reactions - fear, rage
Control body rhythms

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69
Q

What is the kappa receptor responsible for?

A

analgesia, diuresis, sedation, miosis, slow GIT transit, dysphori, psychotomimetic effects

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70
Q

What are the Mu receptors responsible for?

A

analgesia, respiratory depression, constipation, euphoria, sedation, miosis and modulation of hormone and neurotransmitter release

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71
Q

What are Delta receptors responsible for?

A

analgesia and modulation of hormone and neurotransmitter release

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72
Q

Which most easily penetrates CSF - CO2, H2O, N2O or O2?

A

CO2 - linked with strict ventilation control
water Co2 and O2 penetrate the brain with ease

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73
Q

Describe the Fovea Centralis

A

The pit in the macular part of the retina which allows for maximum acuity of vision.
It is a thin portion of the retina free of rods.
It has densely packed cones.
Provides a direct pathway to the brain.
Few overlying cells and no blood vessels.

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74
Q

What is the main excitatory transmitter in the brain and spinal cord?

A

Glutamate.

Aspartate is also excitatory

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75
Q

The sensation for cold is transmitted by?

A

the lateral spinothalamic tracts
is a crossed sensorimodality
mediated by typa A delta fibres
relayed by the thalamus

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76
Q

what doe the lateral spinothalamic tracts transmit?

A

pain and temperature

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77
Q

what do the anterior/ventral spinothalamic tracts transmit?

A

crude touch and pressure

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78
Q

What do the dorsal columns transmit?

A

fine touch, two point discrimination, proprioception, vibration sense

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79
Q

Roles of alpha 1 receptors

A

Eyes - mydriasis
Skin & splanchnic vessels – constriction
Skeletal muscle - constriction / dilation
Bronchial glands - increase secretion
GIT motility & tone - decreased - contraction of GIT sphincters
Contraction of urinary sphincter
Contraction of pregnant uterus
Ejaculation in male
Skin pilomotor muscles - contraction
Liver - glycogenolysis - pancreas acini - decrease secretion
Salivary glands - thick, viscous secretion

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80
Q

What will happen with a dissection of the lateral spinal cord?

A

Will damage the lateral corticospinal tract, which decussates in the pyramids, resulting in loss of cortical control of motor function on the ipsilateral side, causing ipsilateral hyperreflexia

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81
Q

What does monamine oxidase breakdown?

A

MOA - A breaks down;
serotonin
melatonin
noraderenaline
adrenaline
dopamine

MOA - B breaks down;
Phenethylamine
benzylamine

Both;
dopamine
tyramine
trypatmine

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82
Q

Formation of adrenaline

A

Phenylalanine is converted to Tyrosine
Tyrosine to L-Dopa by tyrosine hydroxylase
L-Dopa to Dopamine by DOPA decarboxylase
Dopamine to noradrenaline by dopamine Beta hydroxylase
Noradrenaline to adrenaline by PNMT.

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83
Q

Formation of serotonin

A

Tryptophan to 5-HTP by tryptophan hydroxylase
5-HTP to sertonin by Dopa decarboxylase
Serotonin broken down by MAO to 5-HIAA

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84
Q

Describe acetylchoinesterase?

A

Breaksdown acetylcholine by hydrolysis to ACh to choline and acetate in the synaptic cleft.

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85
Q

Inhibitory neurotransmitters increase the post synaptic conductance of which of the following; Chloride, sodium, calcium, magnesium?

A

Chloride
Chloride conductance is important to both GABA and glycine functioning as inhibitory neurotransmitters

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86
Q

Describe CSF?

A

CSF is 150mls, production of 550ml/day
CSF turnover is 3.7 times a day.
50-70% of CSF is formed in the choroid plexuses.
Absorbed through the arachnoid villi into veins, mainly the cerebral venous sinus.
Has the same composition as cerebral extracellular fluid.
Has higher concentration of Mg than plasma.
Has lower concentration of Ca than plasma.
Osmolility is the same as plasma.

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87
Q

Describe Excitatory Postsynaptic Potentials (EPSP)?

A

Produced by depolarization of the postsynaptic cell membrane immediately under the presynaptic ending.
Excitatory transmitter opens Na and Ca channels in the post synaptic membrane.
The area of current flow is so small and does not drain enough positive charge to depolarize the whole membrane.
An EPSP is created in one synaptic knob.
Activity in more than one synaptic knob creates spatial summation.
Repeated afferent stimuli causes new EPSPs before old ones decay.
Response of EPSPs is proportionate in size to strength of the afferent stimuli.

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88
Q

What cells create myelin in the CNS and what cells in the PNS?

A

Oligodendrocytes in CNS
Schwann cells in the PNS

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89
Q

Local anaesthetics work most strongly on which fibres?

A

Type C (then type B, then type A)

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90
Q

Describe Polio

A

Polio invades the CNS and replicates in the motor neurons of the spinal cord and brainstem.
Commonly the anterior horn motor neurons.
The posterior horns of the spinal cord and the cranial motor nuclei are sometimes involved.
Does not involve the dorsal root ganglion.

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91
Q

What is the order of the structures conveying visual sensation?

A

Optive nerve
Optic Chiasm
Optic tract
Lateral geniculate body
Occipital cortex

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92
Q

Describe the ciliary muscle

A

smooth muscle responsible for lens accomodation
contained within the ciliary body
contraction of the ciliary muscle enables the lens to focus light onto the retina by changing its shape

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93
Q

what lesion causes loss of peripheral vision or macular sparing

A

occipital lesion

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94
Q

Describe meningiomas

A

Meningiomas are predominantly benign tumours of adults, usually attached to the dura, that arise from the meningothelial cell of the arachnoid.
They are slow growing lesions.
They are uncommon in children and generally show a female predominance (3:2).
Meningiomas often express progesterone receptors and may grow more rapidly during pregnancy

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95
Q

Describe MS

A

MS is an autoimmune demyelinating disorder characterised by distinct episodes of neurological deficits, separated in time, attributable to white matter lesions that are separated in space.
It is the most common of the demyelinating disorders.
Women are affected twice as often as men.
Onset in children or after the age of 50yr is rare.
The frequency of relapses tend to decrease during the course of time, but there are steady neurologic deterioration in most affected individuals.
CSF has a mildly elevated protein level and in one third of cases there is moderate pleocytosis.
IgG levels are increased and oligoclonal bands are usually observed on immunoelectrophoresis

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96
Q

Describe Rabies

A

Rabies is a severe encephalitis transmitted to humans by the bite of a rabid animal-usually a dog or various wild animals. Exposure to certain species of bats, even without a known bite, can also lead to rabies.
Negri bodies, the pathognomonic microscopic finding, are cytoplasmic, round to oval, eosinophilic inclusions that can be found in pyramidal neurons of the hippocampus and Purkinje cells of the cerebellum, sites usually devoid of inflammation.
Since the virus enters the CNS by ascending along the peripheral nerves from the wound site, the incubation period (1-3months) depends on the distance between the wound and the brain.
The disease begins with non specific symptoms of malaise, headache, and fever, but the conjunction of these symptoms with local paraesthesia around the wound is diagnostic.

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97
Q

Describe atraumatic intracerebral haemorrhage?

A

Occurs in middle to late adult life, peak incidence 60yrs.
The 2 main aetiologies are hypertension and cerebral amyloid angiopathy (CAA).
Other local or systemic factors may cause or contribute: coagulation disorders, neoplasms, vaculitis, aneurysms and vascular malformations.
Hypertension accounts of >50% of clinically significant haemorrhages and for 15% of deaths in patients with chronic hypertension.
These haemorrhages occur in the putamen (50-60%), thalamus, pons and cerebellar hemispheres.
CAA bleeds are often restricted to the leptomenigeal and cerebral cortical arterioles and capillaries

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98
Q

Describe retinoblastomas?

A

Retinoblastoma is the most common primary intraocular malignancy of children.
Cell of origin is neuronal.
Approximately 40% of cases occur in patients who inherit a germline mutation of one RB allele.
Chemotherapy is often the first of treatment to attempt to reduce the tumour followed by laser treatment or cryopexy.
Spread is to the brain and bone marrow and seldom to the lungs.
Prognosis is poor if there is extra ocular extension and invasion along the optic nerve, and by choroidal invasion

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99
Q

What metabolite accumulates in stroke propagating cellular damaging?

A

Glutamate
Ischaemia leads to ATP depletion in stroke by multiple mechanisms, one which releases glutamate. This causes cell damage via calcium influx through NMDA-type glutamate receptors

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100
Q

What is the most important ion for cardiac resting membrane potential?

A

Potassium

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101
Q

What is calmodulin?

A

Calmodulin is involved in smooth muscle contraction, synaptic function, protein synthesis, activating calcium channels and t cells, and activating phosphorylase.

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102
Q

What does calmodulin do to smooth muscle?

A

Ca binds to calmodulin, and the resulting complex activates calmodulin-dependent myosin light chain kinase.
This enzyme catalyses the phosphorylation of the myosin light chain in serine at position 19, increasing its ATPase activity,
leading to smooth muscle contraction.

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103
Q

Describe resting nerve membrane potential

A

usually -70mV in the cell
Na is actively transported out of neurons
K is actively transported in
K channels maintain the resting membrane potential

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104
Q

For excitable tissue, changes in external potassium will affect?

A

the resting membrane potential.
hyperkalaemia decreases resting membrane potential

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105
Q

For excitable tissue changes in external Na affects?

A

the strength of the action potential

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106
Q

What is bradykinin?

A

Bradykinin is a potent endothelium-dependent vasodilator which leads to hypotension, causes contraction of non-vascular smooth muscle, increases vascular permeability and also is involved in the mechanism of pain.
Bradykinin also causes natriuresis, contributing to an even more drop in blood pressure. There is an acceleration of the heart rate

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107
Q

initiation of smooth muscle contraction is due to ?

A

Calcium influx
via voltage gated and ligand gated Ca channels

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108
Q

with fibre type A, what is the function of alpha?

A

proprioception, motor (somatic)

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109
Q

with fibre type A, what is the function of beta?

A

touch (long hairs), pressure

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110
Q

with fibre type A, what function is gamma?

A

motor (muscle spindles)

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111
Q

with fibre type A, what function is delta?

A

pain, cold, tough (small hairs)

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112
Q

what function is fibre type B?

A

preganglionic autonomic

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113
Q

with regards to fibre type C, what function is dorsal root?

A

Pain, temperature, mechanoreceptor, reflex responses

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114
Q

with regards to fibre type C, what is the function of the sympathetic type?

A

postganglionic synatpic

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115
Q

Which nerve fibres are most susceptible to hypoxia?

A

Fibre type B ( then A then C)

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116
Q

Which nerve fibres are most susceptible to pressure?

A

Type A (then B then C)

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117
Q

Morphology of Cardiac muscle cells

A

Cardiac muscle striations are similar to skeletal muscle
Z lines are present
Muscle fibres branch and interdigitate
Intercalated discs - strong unions between fibres, extensive series of folds at the Z line
Gap junctions - along the side of the muscle fibres next to the disks, provide low resistance bridges for the spread of excitation

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118
Q

Contractile mechanism in skeletal muscle depends on what 4 proteins?

A

Myosin II
Actin
Tropomysin
Toponin (T, I, C )

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119
Q

In skeletal muscle what are the thick filaments?

A

made of myosin II
have two heads and a long tail
Heads form cross links to actin
contain an actin biding site and a catalytic site that hydrolyses ATP

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120
Q

In skeletal muscle what are thin filaments?

A

Two chains of Actin that form a double helix
Tropomyosin forms long filaments located in the groove between the two chains
Troponin are small globular units located in intervals

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121
Q

What do the three types of Troponin do in skeletal muscle?

A

Troponin T - binds the other troponin components to tropomyosin
Troponin I - inhibits the interactions of myosin with actin
Troponin C - contains the binding sites for the Ca that initiates contraction

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122
Q

In a sarcomere what is the I band?

A

The pale band containing the z disk plus the areas actin actin filaments not overlapping with myosin filaments
Becomes shorter during contraction as overlap increases

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123
Q

In a sarcomere what is the A band?

A

the dark band which extends the length of the myosin filament
never changes length

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124
Q

In a sarcomere what is the H zone?

A

the area of myosin filaments not overlapping with actin filaments
becomes shorter during contraction as overlap increases

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125
Q

In a sarcomere what is the M line?

A

dark staining line where myosin filaments are anchored to one another in the centre of the sarcomere

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126
Q

what does Na/K/ATPase do to Na and K?

A

3Na out from the cell
2K into the cell

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127
Q

visceral smooth muscle is characterised by?

A

Instability of its membrane potential
continuous irregular contractions = maintained partial contraction = tonus

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128
Q

what is the resting potential of cardiac muscle cell (non pacemaker)

A

-90mV

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129
Q

what happens to visceral smooth muscle when it is stretched?

A

it contracts

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130
Q

Describe type II muscle fibres

A

Type II muscle fibres- Fast; glycolytic; white.
Myosin isoenzyme ATPase rate= fast
Calcium pumping capacity of sarcoplasmic reticulum=High
Diameter= large
Glycolytic capacity= high
Oxidative capacity= Low

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131
Q

Describe cAMP

A

cAMP is an important secondary mechanism.
It is also known as 3’,5’-monophosphate.
It is formed from ATP by the action of adenylyl cyclase enzyme.
cAMP is then converted to the physiological inactive 5’AMP by phosphodiesterase.
cAMP activates protein kinase A that catalyses the phosphorylation of proteins

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131
Q

where is B12 absorbed

A

in the ileum

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132
Q

In the intracellular fluid what is the most prevelant cation and anion

A

cation is K+
anion is Protein -

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133
Q

Describe protein digestion

A

begins in the stomach
absorption takes place rapidly in the duodenum and jejunum
at least 7 different transport systems are required for absorption
Pepsinogen I is found only in the acid secreting regions of the stomach. Pepsinogen II is also found in the pyloric region.

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134
Q

Describe fat absorption

A

Most fat digestion begins in the duodenum
pancreatic lipase being one of the most important enzymes

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135
Q

Describe iron absorption

A

Regulated by recent dietary intake, iron stores and level of erythropoeisis in bone marrow
Almost all is absorbed in the duodenum
Is increased by Vitamin C

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136
Q

28-year-old woman is found to have megaloblastic anaemia. She reports tingling of her hands bilaterally. She is likely deficient in a vitamin absorbed in which part of the gastrointestinal tract?

A

Ileum
B12 deficency

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137
Q

Where are Baroreceptors located?

A

Carotid sinus, aortic arch, walls of right and left atria, entrance of superior and inferior vena cava, pulmonary veins and circulation

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138
Q

What does gastrin do?

A

Gastrin stimulates gastric acid secretion, increases gastric motility, and increases pancreatic and biliary secretions.

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139
Q

What is the Poiseuille-Hagen Formula?

A

Q = (P1-P2) x [pie x r4] x 1/8nl or
Flow = [(Pressure difference) x pie x r^4/ [viscosity x 8 x L]
P = pressure difference between two ends of the tube
n = viscosity
r = radius
L = length of tube
Q = flow

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140
Q

What is flow?

A

proportionate to pressure difference at 2 ends of a tube

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141
Q

what is endothelium derived relaxing factor?

A

also known as NO

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142
Q

How does radius alter resistance?

A

change in radius alters resistance to the 4th power
therefore a 2 fold increase in radius decreases resistance by a factor of 16

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143
Q

what contributes to venous blood flow?

A

the pumping of the heart
skeletal muscle contraction
intrathoracic pressure variations

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144
Q

the ‘c’ wave of the jugular pulse is due to ?

A

transmitted pressure due to tricuspid bulging in isovolumetric contraction

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145
Q

the a wave of the jugular pulse is due to ?

A

due to atrial systole, rise in venous pressure

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146
Q

the v wave of the jugular pulse is due to ?

A

the v wave mirrors the rise in atrial pressure before the tricuspid wave opns during diastole

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147
Q

what stimulates endothelin 1?

A

angiotensin II
catecholamines
GF
hypoxia
insulin
oxidised LDL
HDL
shear stress
thrombin

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148
Q

what inhibits Endothelin 1?

A

NO, ANP, PGE2, prostacyclin

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149
Q

Constriction of arterioles?

A

Local factors: Decreased local temperature, autoregulation
Endothelial products: Endothelin 1, locally released platelet serotonin
Circulating hormones: Epinephrine- EXCEPT in skeletal muscle and liver, noradrenaline, AVP, angiotensin II, Circulating Na-K ATPase and neuropeptide Y
Neural factors: Increased discharge of sympathetic nerves

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149
Q

Dilation of arterioles?

A

Local factors: Increased CO2, K, adenosine, lactate and local temperature. Decreased O2 and local pH.
Endothelial products: NO, kinins and prostacyclin.
Circulating hormones: Epinephrine in skeletal muscle and liver, CGRP alpha, substance P, histamine, ANP and VIP.
Neural factors: Decreased discharge of sympathetic nerves and activation of sympathetic cholinergic vasodilator nerves to skeletal muscle.

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150
Q

Phases of the valsalva manouvre

A

Phase 1: Onset of straining and the beginning of an increase in intrathoracic pressure.
Phase 2: The persistent straining and maintenance of the increased intrathoracic pressure.
Phase 3: Release of breath-holding and glottic pressure with a sudden drop in the intrathoracic pressure.
Phase 4: shortly after release of straining, Sudden increase in cardiac output and aortic pressure which stimulates the baroreceptors causing a bradycardia

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151
Q

Describe peripheral chemoreceptors

A

they are in the carotid and aortic bodies
primarily activated by reduction in paO2 and pH
respond to increase in paCO2
they are responsible for all the increase of ventilation

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152
Q

What is the variation of the pressure in the capillaries?

A

in nail bed is 32mmHg at the arteriolar end
15mmHg at the venous end
but also ?5mmHg at arterolar end and 0 at venous end

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153
Q

Describe the blood in the capillaries

A

blood moves slowly
transit time from arteriolar end to venous is 1-2 seconds
5% of circulating blood is in capillaries
the only part where O2 and nutrients can enter the interstitial fluid and CO2 removed

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154
Q

Where are chemoreceptors located

A

in the carotid body at the bifurcation of the common carotid artery and the aortic body

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155
Q

Mechanisms of heat loss at 21 degrees celsius

A

70%: radiation and conduction
27%: vaporization of sweat
2%: respiration
1%: urination and defecation

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156
Q

what % of ATP is used for different processes?

A

27% is used for protein synthesis,
24% for Na/K/ATPase to help set membrane potential
9% by gluconeogenesis
6% by Ca2+ ATPase to maintain a low cytosolic Ca2+ concentration
5% by myosin ATPase
3% by ureagenesis.

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157
Q

to diagnose SIADH what plasma and urine values do you need?

A

Euvolaemic hyponatraemia <135mmol/L
Plasma osmolality <280mOsm/L
Urine osmolality >100mOsm/L
Urine sodium >20mmol
Urine osmolality>serum osmolality

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158
Q

Causes of SIADH

A

malignancy, CNS, lung infections and granulomatous disease
psychoactive drugs-MAOI, SSRI, TCI, NSAIDS, chlorpromazine and chemotherapeutic drugs

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159
Q

Regarding blood buffers, what is the HCO3:H2CO3 ratio at a PH of 7.4?

A

pH = pka + log HCO3/H2CO3
7.4 = 6.1 + log HCO3/H2CO3
1.3 = log HCO3/H2CO3
which somehow = log 20 =1.3?

pH7.4=20
pH6.0=0.9
pH7.1=10
pH7.3=16

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159
Q

Regarding fluid composition what % of body weight is ICF

A

40%

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160
Q

How do you calculate the anion gap?

A

(Na+ + K+) – (Cl- + HCO3-) = Anion Gap

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161
Q

What can cause an anion gap metabolic acidosis?

A

Methanol, metformin, uraemia, renal failure, ketoacids, lactic acids, ethanol, salicylates, ethylene glycol, paraldehyde, toluene, iron and cyanide.

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162
Q

What is the principe interstitial buffer ?

A

carbonic acid-bicarbonate system (CA-B). The CA-B system will function without the carbonic anhydrase enzyme

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163
Q

In chronic acidosis, the major adaptive buffering system in the urine is

A

Ammonium NH4

(ammonia) NH3 + H = NH4

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164
Q

What is the major buffer in interstitial fluid?

A

Bicarbonate

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164
Q

What is the major buffer in intracellular fluid?

A

Phosphate

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165
Q

Describe Vitamin D metabolism

A

Vitamin D3 is produced in the skin from 7-dehydrocholesterol by action of sunlight.
Metabolised by p450
25-hydroxilation occurs in the liver, converting vitamin D3 into 25-hydroxycholecalciferol
in the kidney this is converted to 1,25 dihydroxycholecalciferol and less active 24,25 duhydroxycholecacliferol

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166
Q

where is platelet activating factor produced?

A

by neutrophils, basophils, platelets and endothelial cells

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167
Q

Define hypertrophy

A

increase size of cells and so increase size of the organ. No new cells
The phenotype of an individual cell me be altered in hypertrophy

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168
Q

What is dystrophic calcification

A

In area of necrosis of any type
Inevitable in atheromas of advanced atherosclerosis

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169
Q

Define apoptosis

A

a pathway of cell death when cells activate enzymes that degrade the cells own nuclear DNA and proteins.
Fragments break off that are targets for phagocytes.
does not illicit an inflammatory response

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169
Q

Define metaplasia

A

a reversible change when cell type is replaced by another
eg squamous to columnar in Barrots

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170
Q

what are the two main process of necrosis

A
  1. Denaturation of intracellular proteins, coagulative necrosis (with initial maintenance of basic cell structure)
  2. Enzyme digestion of organelles, liquefactive necrosis
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171
Q

morphological features of necrosis

A

Eosinophilic (pink) cells due to loss of RNA mediated basophilia
Myelin figures - phospholipid masses that can replace cells when they necrose
Fragmented membranes
Nuclear changes
Autolysis - intrinsic cell digestion
Heterolysis - digestion by lysosomal enzymes of immigrant leukocytes

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172
Q

2 main characteristics of apoptosis

A

Chromatic condensation and DNA fragmentation

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173
Q

what happens when ATP is depleted 5-10%

A
  • NaKATPase fails, raise in intracellular Na, loss of K = cell swelling
  • Increased AMP stimulate anaerobic metabolism
  • Ca Mg ATPas fails, increasing intracellular Ca
  • Detachment of ribosomes causing reduced protein synthesis
  • Misfolding of proteins due to deprivation of O2and glucose - unfolded protein response
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174
Q

What happens to a cell with loss of calcium homeostasis

A

Increase Ca activates phospholipidases, proteases, ATPases and endonucleases

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175
Q

How are oxygen derived free radicals initiated ?

A

Radiation
exogenous chemicals
reduction-oxidation reactions in metabolism
transition metal reactions
NO

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176
Q

What effect do free radicals have on a cell

A

Phospholipid membrane breakdown through lipid preoxidation
Oxidative modification of proteins result in fragment proteins
DNA lesions as free radicals react with nucleobase thymine, produce single stranded breaks in DNA

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177
Q

Cellular mechanisms to remove free radicals

A
  • Antioxidants
  • Metal storage proteins
  • enzymes that act as free radical scavenging systems
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178
Q

Describe ATP depletion causing anaerobic glycolysis

A

glycogen is quickly depleted
lactate and inorganic phosphate produced
drops intracellular pH

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179
Q

what is the sentinel event for irreversible injury of a cell

A

damage to membranes

180
Q

Types of necrosis

A

Coagulation
Liquefaction
Caseous
Fat

181
Q

what is coagulation necrosis

A

most common
usually occurs after irreversible ischaemic cellular damage
denaturation of cytoplasmic proteins with preservation of framework of the coagulated cell

182
Q

What is liquefaction necrosis

A

when autolysis and heterolysis prevail over protein denaturation
necrotic area that is soft and filled with fluid

183
Q

What is caseous necrosis

A

soft friable cheesy material
amorphous eosinophilic material with cell debris
eg tuberculous lesion

184
Q

what is fat necrosis

A

necrosis in adipose tissue
chalky white area - fat saponification

185
Q

morphological features of apoptosis

A

Cell shrinkage
Chromatin condensation and fragmentation
Cellular blebbing and fragmentation of apoptopic bodies
Phagocytosis
Lack of inflammation

186
Q

Biochemical features of apoptosis

A

Protein cleavage by caspases
Protein cross linking by transglutaminase
Cleavage of DNA
Plasma membrane alterations - recognition of dead cells by macrophages

187
Q

what is the extrinsic pathway in Apoptosis

A

Death receptor initiated
TNF and Fas receptors on cell surface contain a death domain that when activated leads to activation of intracellular caspases

188
Q

What is the intrinsic pathway in Apoptosis

A

Mitochondrial pathway
Loss of survival signals or cell stress causes change in protein expression on mitochondrial surface and increased permeability to cytochrome C

189
Q

Define dysplasia

A

loss in the uniformity of individual cells and in their architectural orientations
Exhibit considerable pleomorphism

190
Q

what type of wound healing are surgical wounds

A

primary intention

191
Q

what is the wound strength when sutures are removed at 1 week

A

10%

192
Q

order of WBC extravasation

A

Rolling along the vessel wall
Activation
Adhesion to endothelium
Transmigration

193
Q

what inflammatory markers are responsible for fever

A

Interleukin 1
TNF
Prostoglandin

194
Q

What is the most common mechanism of vascular leakage in acute inflammatory response

A

endothelial cell contraction

195
Q

What is dystrophic calcification

A

Occurs in nonviable or dying tissue in all area of necrosis
formed by crystallin calcium phosphate
Often causes organ dysfunction

196
Q

Reversible cell injury features

A

cell swelling
fatty change
plasma membrane blebbing
loss of microvilli
mitochondrial swelling
dilation of the ER
eosinophilia
clumping of chromatin

197
Q

in wound healing when is neovascularisation maximal

A

day 5

198
Q

in wound healing when does neutrophil infiltration occur

A

24 hours

199
Q

what happens by day 3 in wound healing

A

neutrophils have been largely replaced by macrophages
granulation tissue progressively invades the incision space

200
Q

what is a normal and what is an anaplastic nuclear to cytoplasmic ratio

A

normal 1:4 or 1:6
anaplasie 1:1

201
Q

loss of which of the following extracellular matrix components has most likely occurred in osteoarthritis?

A

Hyaluronan
loss of articular hyaline cartilage

202
Q

what is the first thing to occur in inflammation

A

vasoconstriction lasting only seconds

203
Q

chronic inflammation is characterised by these sets of reactions

A
  • Infiltration with mononuclear cells including macrophages, lymphocytes, plasma cells
  • Tissue destruction, largely induced by inflammatory cells
  • Repair involving new vessel proliferation and fibrosis
204
Q

In acute inflammation what are the changes in vascular caliber and flow?

A

Transient vasoconstriction
Vasodilation
locally increased blood flow
Microvasculature becomes more permeable
Protein rich fluid moves into the extravascular tissues, causing RBC more concentrated
slowing of circulation, stasis
Leukocytes accumulate, margination.

205
Q

what contribute to wound contraction

A

Myofibroblasts

206
Q

Epithelial closure in healing by primary intention occurs when?

A

24 to 48 hours

207
Q

What cells are first involved in healing

A

neutrophils

208
Q

What is the triple response of Lewis

A

Redness, Flair, Wheal
Redness - direct effect of injury causing capillary dilation
Flair - arterial dilation by substance P, CGRP
Wheal - oedema

209
Q

what mediators control vasodilation in inflammation

A

Prostoglandins
NO
Histamine

210
Q

what mediators control increased vascular permeability in inflammation

A

Histamine and serotonin
C3a and C5a
Bradykinens
Eukotreins C D
PAF
Substance P

211
Q

what mediators control chemotaxis, leukocyte recruitment and activation

A

NF I
Chemokines
C3a C5a
Eukotriene B

212
Q

What mediators control fever in inflammation

A

IL1
TNF
Prostaglandins

213
Q

what mediators control pain in inflammation

A

Prostaglandins
Bradykinin

214
Q

what mediators control tissue damage in inflammation

A

lysosomal enzymes of leukocytes
reactive oxygen species
NO

215
Q

what is pain mediated by during the inflammatory process?

A

Bradykinin

216
Q

3 mechanisms that inactivate free radical reactions

A

Glutathione (GSH) peroxidases
Catalase
Endogenous or exogenous antioxidants (vitamine E, A, C)

217
Q

What do RAS proteins do

A

transduce signals from growth factor receptors that have intrinsic tyrosine kinase activity
Transducing the mitogenic signal from the epidermal cell membranes to the nucleus

218
Q

What is dystrophic calcification

A

happens in any type of necrosis
inevitable in atheromas
formed by crystalline calcium phosphate mineral

219
Q

what are macrophages derived from

A

monocytes

220
Q

In injury what are the two phases of calcification?

A
  1. Initiation
    extracellular, membrane bound vesicles
    intracellular occurs in mitochondria
  2. Propagation
221
Q

In acute inflammation what is exudate

A

Inflammatory extravascular fluid, high protein concentration, cellular debris, sepcific gravity >1.020

222
Q

In acute inflammation what is transudate

A

Fluid with low protein content, specific gravity <1.012

223
Q

Define pus

A

Inflammatory exudate rich in leukocytes (neutrophils), debris of dead cells and microbes

224
Q

3 steps of phagocytosis

A
  1. recognition and attachment
  2. engulfment
    extension of cytoplasm (pseudopods) flow around the particle
  3. killing and degradation
225
Q

morphologic patterns in serous inflammation

A

moderate inflammation with few pro-inflammatory mediators
limited lymphocyte activation
accumulation of fluid
eg blister

226
Q

morphologic patterns in fibrinous inflammation

A

vascular permeability allowing fibrinogen in
scarring due to conversion of fibrinogen to fibrin, called organisation

227
Q

morphology of suppurative inflammation

A

build up of leukocytes and macrophages leading to liquefactive necrosis, build up of puss
eg abscess

228
Q

morphologic patterns in ulcers

A

acute inflammation with sloughing caused due to location, fibrous changes at base and edge

229
Q

In cell injury what are the effects of histamine

A

Dilation of arterioles
Increased permeability of venules
acts on microcirculation mainly via binding to H1 receptor on endothelial cells

230
Q

in cell injury what is Serotonin (5HT)

A

actions similar to histamine
present in platelets and enterochromaffin cells

231
Q

In acute inflammation what is the Classical Complement pathway

A

Triggered by C1 to antibody combined with antigen
activates C3 to C3 a and C3 b
1. C3a and C5a causes inflammation
2. C3b causes phagocytosis
3. Formation of Membrane Attack Complex from C5b to C9

232
Q

In acute inflammation what is the Alternative Complement pathway

A

triggered by microbial surface molecules
then the complement pathway from C3 to C9

233
Q

In acute inflammation what is the Lectin Complement pathway

A

Plasma mannose-bidning lectin binds to carbohydrates on microbes which activates C1 and so on to C3 C5 and MAC

234
Q

in acute inflammation what is the role of kinins

A

Converts plasma proteins called kininogens by kallikreins to vasoactive peptides kinins
results in the release of bradykinin that causes;
- increased vascular permeability
- contraction of smooth muscle
- dilation of blood vessels
- pain

235
Q

In acute inflammation what are the actions of Platelet Activating Factor (PAF)

A

stimulates platelets
vasoconstriction
bronchoconstriction
increased leukocyte adhesion to endothelium, chemotaxis, degranulation, oxidative burst

236
Q

what do macrophages secrete associated with tissue injury

A

Proteases
Chemotactic factors
Arachidonic acid metabolites
Reactive oxygen species
NO
Coagulation factors
Complement components

237
Q

what products do macrophages produce associated with fibrosis

A

growth factors
Cytokines IL - 1 TNF
PAF

238
Q

in inflammation what is the main cell type after 48 hours

A

Macrophages

239
Q

What are the 3 major steps in Fibrosis

A

Angiogenesis
Scar formation
Scar remodelling

240
Q

with regards the healing by first intention what happens initially

A

a clot

241
Q

with regards to healing by first intention what happens at 3-24 hours

A

neutrophils infiltrate the clot
epithelial closure by 24-48hr

242
Q

in healing by first intention what happens at Day 3

A

neutrophils have been replaced by macrophages
granulation tissue

243
Q

in healing by first intention what happens at day 5

A

Incision space is filled with granulation tissue
maximal neovascularisation
appearance of collagen fibrils
maximal epithelial proliferation

244
Q

in healing by first intention what happens at week 2

A

proliferation of fibroblasts
continued collagen accumulation
production of a scar
collagen deposited early is type III, replaced by adult type I

245
Q

what % of total body weight is Extracellular fluid

A

20%

246
Q

in a bag of 0.9% NaCl how much does it contain of;
NaCl in grams
mmols /L of Na
pH range
osmolality

A

9 grams
150mmomls/L
4-7.0
300mOsm

247
Q

which has highest Mg, phosphate and potassium concentraion ECF or ICF

A

ICF

248
Q

The ratio of HCO3- ions to carbonic acid at a pH of 7.1 is?

A

10

249
Q

Hydrogen iron concentrations with these pH
4.5
7.0
7.7
8.0

A

4.5=0.03
7.0=0.0001
7.7=0.00002
8.0=0.00001

250
Q

what does Calmodulin do to smooth muscle

A

causes smooth muscle contraction
it binds to Ca activating myosin light chain kinases
this with ATP activates myosin to bind to Actin for contraction

251
Q

what is bradykinin

A

a potent endothelium dependent vasodilator
contraction of visceral muscle ( non vascular smooth muscle)
increases vascular permeability
involved in mechanism of pain

252
Q

what are the 3 fibre typres

A

A B C

253
Q

what are the A nerve fibre types

A

alpha = somatic motor, proprioception
beta = touch, pressure
gamma - motor to muscle spindles
delta = pain, temperature, touch

254
Q

what are the B nerve fibre types

A

preganglionic autonomic

255
Q

what are the C nerve fibre typres

A

post ganglionic sympathetic
dorsal root pain temperature

256
Q

in smooth muscle contraction what is the
I band
H zone
A band

A

I band = only actin, decreases
H zone = only myosin, decreases
A band = length of myosin, unchanged

257
Q

What occurs after stretching intestinal smooth muscle?

A

it depolarises
contracts
increase in tone

257
Q

increasing extracellular potassium ion concentration will do what to the resting membrane potential

A

decrease it

258
Q

what is the main inhibitory neurotransmitter of the spinal cord

A

Glycine

259
Q

what are the principle hypothalamic regulatory mechanisms

A

Temperature
Hunger
thirst
sexual behaviour
neuroendocrine control
defensive reactions
body rhythms

259
Q

what is the kappa receptor is responsible for

A

analgesia
diuresis
sedation
dysphoria
miosis
slow GIT

260
Q

what is the Mu receptor responsible for

A

analgesia
respiratory depression
constipation
euphoria
sedation
miosis
modulation of hormone and neurotransmitter release

261
Q

what is the Delta receptor responsible for

A

analgesia
modulation of hormone and neurotransmitter release

262
Q

what gas penetrates CSF the fastest

A

CO2

263
Q

what is the major excitatory transmitter in the spinal cord

A

Glutamate

264
Q

what is transmitted through the lateral spinothalamic tract

A

pain and temperature

265
Q

what is transmitted through the anterior spinothalamic tract

A

crude touch
pressure

266
Q

what do the dorsal columns transmit

A

fine touch, two point discrimination
proprioception
vibration

267
Q

how is the sensation of cold transmitted

A

by lateral spinothalamic tracts
is a crossed sesorimodality
mediated by type A delta fibres
relayed by the thymus

268
Q

Anterolateral dissection of the spinal cord is associated with

A

Ipsilateral hyperreflexia
as it causes damage to lateral corticospinal tract which decussates at the pyramids
loss of control of motor function

269
Q

what does MOA-A break down

A

Serotonin
melatonin
Noradrenaline
Adrenaline
dopamine, tyramine, tryptamine

270
Q

what does MOA-B break down

A

Phenethylamine
benzylamine
dopamine, tyramine, tryptamine

271
Q

in the formation of adrenaline what is the sequence

A

Tyrosine -> Dopa -> Dopamine ->noradrenaline -> adrenaline

272
Q

in formation of adrenaline ho is Dopa formed

A

from tyrosine hydroxylase
Tyrosine -> Dopamine

273
Q

what metabolises noradrenaline and adrenaline to inactive products

A

COMT
MOA

274
Q

regarding carbohydrate homeostasis in exercise what happens

A

initially muscle utilizes glycogen stores
also muscle increase uptake of glucose
Plasma glucose initially rises with increased hepatic glycogenolysis
Insulin falls

275
Q

The majority of heat lost by the body at 21 degrees is by

A

radiation

276
Q

what does ATP consist of

A

3 phosphate groups
an adenine ring
ribose sugar

277
Q

what do thyroid hormones do to LDL receptors

A

increase them
resulting in hepatic removal of cholesterol

278
Q

what does PTH do to PO4

A

decreases it

278
Q

what does PTH act on

A

directly on bone to increase resorption and mobilize Ca

279
Q

what does phenytoin, noradrenaline and somastatin do to insulin

A

inhibit insulin secretion

280
Q

what cells produce Glucagon

A

alpha cells of the pancreas

281
Q

what does Glucagon do

A

stimulate gluconeogenesis to produce glucose
half life 5-10 mins

282
Q

What is T4 synthesised from and held in

A

synthesised from tyrosine
held in thyroglobulin

283
Q

Where are T3 and T4 metabolized

A

liver and kidneys

283
Q

A deficiency of parathyroid hormone (PTH) is likely to lead to

A

rise in phosphate and a decrease in plasma Ca
neuromuscular hyperexcitability

284
Q

what happens to glycogen and glucose with Glucocorticoids

A

increase glycogen synthetase
decrease peripheral glucose utilisation
plasma glucose level rises

285
Q

where is B12 absorbed

A

ileum

286
Q

what can increase iron absorption

A

vitamin C

287
Q

where does protein digestion begin

A

stomach

288
Q

what are the nutritional essential amino acids

A

Threonine
Valine
Leucine
Isoleucine
Methionine
Phenylaanine
Lysine

289
Q

The majority of water ingested is re-absorbed where

A

Jejunum

290
Q

what do parietal cells secrete

A

Intrinsic factor

291
Q

what do chief cells secrete

A

pepsinogen and rennin

292
Q

what do eosiophils phagocytose

A

parasites

293
Q

what is the half life of neutrophils

A

6 hours

294
Q

describe the protein in lymph

A

it has different protein content in different areas

295
Q

what do prostoglandins to medullary blood flow and cortical blood flow

A

decrease medullary blood flow
increase cortical blood flow

295
Q

what thins contribute to venous blood flow

A

the pumping of the heart
skeletal muscle contraction
intrathoracic pressure variations

296
Q

Where in the kidney is the tubular fluid isotonic with the renal interstitium?

A

PCT
(water moves passively out of the tubule along the osmotic gradients set up by the active transport of solutes. This maintains isotonicity)

297
Q

what is the anion gap calculation

A

Na - (Cl + HCO3)

298
Q

what type of anion gap is caused by diarrhoea which causes metabolic acidosis

A

normal anion gap

298
Q

what type of anion gap metbolic acidoses does uraemia and rhabdo cause

A

raised

299
Q

Which of the following H+ concentration is compatible with life?

A

0.00000004 mol/l

300
Q

where is carbonic anhydrase found

A

RBC
gastric acid secreting cells
renal tubular cells
NOT in plasma cells

301
Q

In chronic acidosis, the major adaptive buffering system in the urine is

A

Ammonium

302
Q

what is hyperopia

A

Eye too short for refractive power of cornea and lens-
Light focused behind retina

303
Q

what is myopia

A

Eye too long for refractive power of cornea and lens-
light focused in front of retina

304
Q

what is astigmatism

A

Abnormal curvature of cornea-
different refractive power at different axes

305
Q

what is presbyopia

A

Age related impaired accommodation.
(Focusing on near objects),
primarily due to decrease lens elasticity. Often necessitates “reading glasses.”

306
Q

A deep sea commercial diver presents to the ED after suffering a seizure. He has no known seizure activity. What gas is primarily responsible?

A

Oxygen

307
Q

what substances does the saliva contain

A

Na, K, Ca, Mg, Cl, HCO3, PO4, iodine
Mucins (to lubricate food)
IgA, hydrogen peroxide
Epidermal growth factor
alpha-amylase, lingual lipase, kallikrein, antimicrobial enzymes (lysozyme, lactoperoxidase, lactoferrin)
Opiophin: a pain killing substance
Haptocorrin: protein that’s binds B12 to protect it against degradation in the stomach before it binds to intrinsic factor

308
Q

stimulators of endothelin-1

A

Angiotensin II
Catecholamines
GF
hypoxia
insulin
oxidised LDL, HDL
shear stress
thrombin

309
Q

Inhibitors of endothelin-1

A

NO
ANP
PGE2
prostacyclin

310
Q

Where are steroids synthesised in steroid secreting cells?

A

Smooth endoplasmic reticulum

311
Q

what is the main exitatory transmitter in the brain and spinal cord

A

Glutamate

312
Q

Inhibitors of glucagon

A

Somatostatin
Secretin
FFA
Ketones
Insulin
Phenytoin
Alpha-adrenergic stimulators
GABA

313
Q

stimulation of glucagon

A

Amino acids
CCK, gastrin
Cortisol, exercise, infections and other stressors
B adrenergic stimulators
Theophylline and acetylcholine

313
Q

stimulators of gastric acid secretion

A

Gastrin
ACH
histamine

314
Q

Inhibitors of gastric acid secretion

A

VIP
Prostaglandins

315
Q

Which hormone stimulates an increase in the volume of pancreatic juice but not the enzyme content?

A

Secretin

315
Q

Which hormones stimulate an increase in the enzyme rich pancreatic juice?

A

CCK
ACH
Vagus nerve

316
Q

Which organ has the greatest blood flow through it in ml/min?

A

Liver

317
Q

Which organ has the highest percentage of blood flow per 100g?

A

Kidney

318
Q

what are type II muscle fibres

A

Fast glycolytic white
used for sprinting

319
Q

Describe type IIa and IIb muscle fibres

A

IIa - Fast, Oxidative, Glycolytic (FOG) –> Red muscle –> Moderate oxidative capacity –> Fast, fatigue resistant (FR)

IIb - Fast, Glycolytic (FG) –> White muscle –> Low oxidative capacity –> Fast, fatigable (FF)

320
Q

Type II muscle fibre characteristics

A

Myosin isoenzyme ATPase rate= fast
Calcium pumping capacity of sarcoplasmic reticulum=High
Diameter= large
Glycolytic capacity= high
Oxidative capacity= Low

321
Q

is endothelin-1 a vasoconstrictor of vasodilator

A

vasoconstrictor

322
Q

what happens to level of endothelin-1 in CCF or after mI

A

increased

323
Q

where is endothelin-1 found

A

endothelial cells
brain
kidney

324
Q

where is calcitonin found

A

parafollicular cells of the thyroid

325
Q

when is Calcitonin secreted

A

presence of high calcium concentration

326
Q

what is the role of calcitonin on calcium and phsophate

A

lowers circulating calcium and phosphate levels
inhibits bone resorption, increases Ca excretion in the urine

327
Q

EPSP (excitatory postsynaptic potentials)

A

produced by depolarization of the postsynaptic cell membrane immediately under the presynaptic ending.
The excitatory transmitter opens NA or Ca channels producing an inward current.
The area of current flow is so small that it does not drain enough positive charge to depolarize the whole membrane. Instead an EPSP is created.

327
Q

how do EPSPs (excitatory postsynaptic potentials) produce depolarization/ a response

A

Activity present in more than one synaptic knob at the same time creates spatial summation.
Repeated afferent stimuli causing new EPSPs before the old EPSPs has decayed is temporal summation.
therefore NOT all or nothing response but are proportionate in size to the strength of the afferent stimuli.

328
Q

what is equal to the molar mass of a substance divided by its valence

A

Equivalents

329
Q

what secretes secretin

A

S cells
located deep in the glands of the mucosa of the upper portion of the small intestine

330
Q

what does secretin do

A

decreases gastric acid secretion
causes pylorus sphincter contraction
increased secretion of HCO3 by the duct cells of the pancreas and biliary tract
augments action of CCK producing pancreatic secretion of digestive enzymes

331
Q

what triggers the secretion of secretin

A

protein digestion
acid bathing in the mucosa of the upper small intestine

332
Q

when does ketoacidosis occur

A

occurs in starvation, diabetes mellitus and a high fat, low carbohydrate diet

333
Q

what causes ketotic breath odour

A

due to the acetone ketone body

334
Q

When extra blood is transfused, where is it NOT distributed?

A

left ventricle

335
Q

where is the absorption of CSF

A

through arachnoid villi into veins
mainly cerebral venous sinus

336
Q

Ammonia is secreted into the tubular fluid as what molecule

A

NH3

337
Q

in Urine what happens to NH3 (ammonia) and why

A

it reacts with H+ to become NH4+ (ammonium)
this is to maintain the gradient of NH3 for diffusion of ammonia
called nonionic diffusion
in the collecting ducts

338
Q

6 hormones secreted by the anterior pituitary gland

A

TSH
ACTH
LH
FSH
prolactin
growth hormone
B-lipitropin

339
Q

2 hormones secreted by the posterior pituitary are

A

oxytocin
vasopressin

340
Q

what increases 2,3 DPG

A

thyroid hormones
growth factor
androgens
exercise after 60mins

341
Q

Which dopaminergic systems are important for the understanding of schizophrenia

A

Mesolimbic-mesocortical pathway

342
Q

what % of total blood volume is plasma

A

55%

343
Q

how long does it take for the total blood volume to circulate around the body at rest

A

one minute

344
Q

In cardiac and skeletal muscle wat triggers contraction

A

calcium binding to troponin C

345
Q

how does the body temperature fluctuate in a day

A

the temperature is lowest at about 06:00 and highest in the evenings

346
Q

what is cAMP known as

A

3 5 - monophosphate

347
Q

how is cAMP formed

A

formed from ATP by adenylyl cyclase

348
Q

what nerve supplies the external sphincter

A

pudendal nerve

348
Q

when does the first urge to defecate happen

A

at a rectal pressure of 18mmHg

349
Q

where does protein digestion begin and by what

A

stomach
by pepsin

350
Q

where is pepsinogen I found

A

only in the acid secreting regions of the stomach

351
Q

what is pepsins optimal pH

A

1.6 - 2.3

352
Q

what shifts the haemaglobin dissociation curve to the right

A

rise in temp
decrease in ph
increae 2,3 DPG
rise in CO2

353
Q

where is aldosterone secreted

A

produced by the outer section (zona glomerulosa) of the adrenal cortex

354
Q

what is the action of aldosterone on the kidneys

A

promotes sodium reabsorption
potassium secretion

355
Q

what is the resting potential od a neuron

A

-70mV

356
Q

stimuli that decrease secretion of growth hormone

A

REM sleep, glucose, cortisol, FFA, medroxyprogesterone, and IGF-1

357
Q

what happens after a glucose load in a non diabetic person

A

50% is normally burned to H20 and CO2,
5% is converted to glycogen
30-40% is converted to fat in the fat deposits.

358
Q

what happens after a glucose load in a diabetic person

A

Less than 5% is converted to fat, a decrease in the amount burnt to CO2 and H2O
no change in the amount converted to glycogen.
glucose accumulates in the blood stream and spills over into the urine.

359
Q

stimulants of Corticotropin releasing hormone

A

Trauma via the nociceptive pathways,
emotions via the limbic system,
the drive for the circadian rhythm

360
Q

Inhibition of corticotropin releasing hormone CRH

A

Baroreceptor exert an inhibitory (afferent) input via the nucleus of the tractus solitarius.

361
Q

Which metabolite is responsible for maintaining normal parathyroid functioning?

A

Magnesium

362
Q

what do T4 and T3 NOT increase oxygen consumption for

A

adult brains,
testes, uterus,
lymph nodes,
spleen,
the anterior pituitary gland

363
Q

what controls thirst

A

Thirst is under anterior hypothalamus control via osmoreceptors.

364
Q

Demyelination in the CNS affects which cells

A

oligodendrocytes

365
Q

Demyelination of the PNS effects which cells

A

Schwann cells

366
Q

PO2=%sats of Hb
10 %?
20 %?
40 %?
50 %?
60 % ?
90 %?
100 %?

A

PO2=%sats of Hb
10-13.5
20-35
40-75
50-83.5
60-89 (90)
90-96.5
100-97.5

367
Q

To diagnose the syndorme of inappropriate ADH secretion (SIADH), you need the following?

A

Euvolaemic hyponatraemia <135mmol/L
Plasma osmolality <280mOsm/L
Urine osmolality >100mOsm/L
Urine sodium >20mmol
Urine osmolality>serum osmolality

368
Q

What is the main negative intracellular charged molecule found in the intracellular fluid?

A

Protein

369
Q

Regarding nerve fibre type and functions, which of the following nerve fibre is most susceptible to hypoxia?

A

Type B

370
Q

Which of the cell organelles is found in the greatest number in growing cells and synthesise ribosomes?

A

nucleoli

371
Q

Local anaesthetics work most strongly on which fibres?

A

Type C (unmyelinated)
C -> B ->A

372
Q

In intracellular and extracellular fluids what is the Na and K ?

A

NA
Intracellular = 15mmol/L
Extracellular = 150mmol/L
K
Intracellular = 150mmol/L
Extracellular = 5.5mmol/L

373
Q

Which substances are responsible for the increase in the formation of plasmin

A

Activated protein C
Protein S

374
Q

what inhibits release of prolactin

A

dopamine, apomorphine and bromocriptine

375
Q

Effects of insulin on liver

A

Decreased ketogenesis
Increased protein synthesis
Increased lipid synthesis
Decreased gluconeogenesis, increased glycogen synthesis, increased glycolysis

376
Q

what is the oxygen carrying capacity of Hb

A

1.34ml/g

377
Q

Haemoglobin increases the oxygen carrying capacity of blood/plasma by a factor of:

A

70 times

378
Q

describe absorption of vitamin B12

A

binds to intrinsic factor and is absorbed in the terminal ileum.

379
Q

what does vitamin B12 deficiency cause

A

megaloblastic pernicious anaemia
degeneration of posterolateral spinal cord tracts (tingling sensation)

379
Q

What is the principle mechanism by which carbon monoxide exposure induces hypoxia?

A

Reducing the oxygen carrying capacity of Hb

380
Q

What is the order of the structures conveying visual sensation?

A

Optic nerve,
optic chiasm,
optic tract,
lateral geniculate body,
occipital cortex

381
Q

What is the approximate % of blood volume located in the venous system at rest?

A

50-60%

382
Q

Which structure in the eye is directly responsible for accommodation?

A

ciliary muscle

383
Q

Hydrogen ions are secreted primarily in the form of:

A

free form
(then buffered via NH4, H2PO4 and bicarbonate to facilitate further secretion.)

384
Q

Where is most iron absorbed in the gastrointestinal tract?

A

duodenum
facilitated by ferric reductase

385
Q

Mitochondria use what percentage of oxygen?

A

90%

386
Q

The function of nerve fibres with the largest diameter is:

A

proprioception and motor
type A alpha

387
Q

Where is proprioception and vibration transmitted in the spinal cord?

A

Dorsal column

388
Q

What will be the effect of haemorrhage on the vasopressin osmotic response curve, and plasma Na?

A

Shifted upwards and to left, decreased plasma Na

389
Q

Which hormone increases gastric acid secretion, stimulates gastric mucosa proliferation, and stimulates gastric emptying?

A

Gastrin

390
Q

What is the major buffer in intracellular fluid?

A

phosphate and proteins

391
Q

In the action potential of a spinal motor nerve, sodium does not reach equilibrium because of which of the following processes?

A

Closure of Na Channels

392
Q

What makes up 20% of body weight?

A

ECF

393
Q

At what altitude does oxygen concentration significantly drop off?

A

34000feet/ 10400m

394
Q

You test a gentleman’s vibration sense with a 126Hz tuning fork. Where does this travel?

A

medial lemniscal pathway

394
Q

What proportion of ATP is used in the cell for gluconeogenesis?

A

9%

395
Q

A hypoglycaemic patient has the following blood results: Na = 120, K = 6.7. What is the likely cause?

A

Primary adrenal insufficiency

396
Q

TRH stimulates which hormone other than TSH?

A

Prolactin

397
Q

The main function of the colon is to

A

allow for the reabsorption of water, sodium, and other minerals

398
Q

A patient suffers peripheral vision loss in both the right and left eyes, with macular sparing. Where is the lesion?

A

occipital lobe

399
Q

What spinal tract is primarily responsible for motor control of voluntary movements?

A

lateral corticospinal tract

399
Q

What percentage of an oral glucose load is typically metabolized into fat under conditions of excess caloric intake?

A

30-50%

400
Q

What are the functions of the smooth endoplasmic reticulum?

A

Steroid synthesis
carbohydrate metabolism
drug metabolism
calcium regulation
lipid synthesis
gluconeogenesis

401
Q

Which cell type is found predominantly in the periarteriolar sheaths in the white pulp of the spleen?

A

T lymphocyte

402
Q

Which of the cell organelle have no phospholipid bilayer membrane?

A

Centriole

403
Q

Regarding ribosomes;
what doe they synthesise
what are they divided into

A

protein, haemaglobin
two subunits - 65% RNA 35% protein

404
Q

Regarding dystrophic calcification;
where does it occur
what is the serum calcium
what type of calcium deposition
what type of necrosis does it occur in

A

in damaged or dying tissues
normal serum calcium levels
formed by crystalline calcium phosphate
occurs in all areas of necrosis

405
Q

in a cell what are the characteristics of irreversible cell injury

A

lysosomal rupture
disruption/defects of cellular membranes
depletion of ATP

406
Q

products in macrophages that cause tissue injury and fibrosis are

A

arachidonic
metabolites
reactive oxygen species
reactive nitrogen
proteases
cytokines
coagulation factures

407
Q

products in macrophages that cause repair

A

Growth Factor
Fibrogenic cytokines
angiogenic factos
remodelling collagenesis

408
Q

where does metastatic calcification normally occur

A

gastric mucosa
kidneys
lungs systemic arteries and pulmonary veins

409
Q

in the complement system what are the main things C5a does

A

chemotatic for neutrophils
activates the lipoxygenase pathway of arachidonic acid AA metabolism
increases vascular permeability

410
Q

in the complement system what is the main function of C3b

A

when fixed to bacterial cell walls act as opsonins and promote phagocytosis by neutrophils and macrophages

411
Q

where are mast cells derived from

A

bone marrow

412
Q

what provides the energy for mast cell degranulation

A

Adenosine triphosphate (ATP)

413
Q

factors released by macrophages

A

toxic oxygen metabolites
proteases
neutrophil chemotatic factors
coagulation factors
arachidonic AA metabolites
NO
GF
angiogenesis and remodelling collagenases
TNF
IL-1 IL6 IL12
Chemokines

414
Q

what are the steps of phagocytosis

A
  1. recognition and attachment
  2. engulfment
  3. degradation
415
Q

what molecules are involved in migration of leukocytes to site of injury

A

PECAM 1
(platelet endothelial cell adhesion molecule)
ICAM
(intercellular adhesion molecule)
CD31

416
Q

where is C3b derived from and where is it formed

A

derived from the liver
formed in plasma

417
Q

where is histamine derived from

A

mast cells
basophils
platelets

418
Q

where is the kinin system activated

A

plasma

418
Q

where is nitric oxide produced in inflammation

A

macrophages

419
Q

characteristics of non inflammatory oedema/transudate

A

low protein content <2g/dl
specific gravity <1.012
serum cholesterol <45mg/dl
caused by increased hydrostatic pressure and
decreased plasma colloid pressure
elevated ANP
right atrial pressure is high

420
Q

Regarding increased vascular permeability due to endothelial contraction, where is it most common

A

in venules

421
Q

Pathophysiologic categories of oedema

A

Increased hydrostatic pressure
Reduced plasma oncotic pressure
Lypmhatic obstruction
Sodiu retention
Inflammation

422
Q

with amniotic fluid embolism what is;
the rate
the mortality %
risk factors

A

1:40000
80%
Tumultuous labour, multigravids

423
Q

in the coagulation cascade describe the common pathway

A

Factor X has been activated
FXa activates FII ( prothrombin) to FIIa (thrombin)
FIIa activates FI (Fibrinogen) to FIa (fibrin)
then leading to stable fibrin clot

423
Q

In Haemophilia A;
what is the factor deficiency
what % cause disease
what is prolonged

A

FVIII
<1% is severe, 2-5% is moderate, 6-50% is mild
prolonged PTT

424
Q

what is passive hyperaemia and what can cause it

A

congestion or stasis
caused by;
portal hypertension
congesitve cardiac failure
hepatic obstruction

425
Q

definition of shock

A

cellular hypoxia resulting from impaired tissue perfusion

426
Q

Regarding fat embolism;
when does it occur
what is fat embolism syndrome
fatality %
symptoms/findings

A

occurs in 90% of individuals with skeletal injuries, symptoms develop 1-3 days after injury
Fat embolism syndrome is when patient become symptomatic (<10%) - pulmonary insufficiency, neurological symptoms, anaemia, thrombocytopenaoa
10% fatal
can cause diffuse petichial rash 20-50% of cases

426
Q

features of post mortem clot

A

gelatinous due to lack of fibrin
dark red portion of red cells
yellow chicken fat upper portion
usually not attached to underlying wall

427
Q

in blood vessels what are lines of Zahn

A

represent pale platelet and fibrin deposits alternating with darker red cell rich layers
signify a thrombus has formed in flowing blood

428
Q

does pulmonary oedema occur because of right or left sided heart failure

A

left sided heart failure

429
Q

AIDS defining infections include

A

Protozoal and helminthic - pneumocytosis, toxoplasmosis, cryptosporidiosis.
Fungal - candida, cryptococcus, disseminated histoplasmosis, coccidioidomycosis.
Bacterial - mycobacterium, disseminated salmonella infections.
Viral - CMV, HSV, VZV.

430
Q

AIDS defining neoplasms include;

A

Kaposi sarcoma,
beta cell non-Hodgkin lymphoma,
primary lymphoma of the brain
invasive cancer of the uterine cervix

431
Q

with regards to hyperacute graft rejection;
when does it occur
how is it decreased
how is it mediated

A

within minutes to hours
decreased with cross matching
reaction is Ag and Ab (Immunoglobulin deposition ) mediated
these complexes are in the vessel wall, causing endothelial injury and fibrin-platelet thrombi

432
Q

with regards to the Rhesus blood group;
what % of Caucasians are Rh +ve
are there spontaneous agglutinins
when do transfusion reactions occur

A

85%
spontaneous agglutinins never occur
first transfusion of Rh+ blood will create anti D titres, this will cause a transfusion reaction any time in the future if transfused again

433
Q

regarding T lymphocytes;
where do they develop
what % of blood lymphocytes
what forms the TCR complex
what type of hypersensitivity

A

thymus
60-70%
T cell receptor plus CD3 form TCR complex
Type IV hypersensitivity

434
Q

type 1 hypersensitivity primary mast cell mediators

A

Heparin
Adenosine
Histamine
Eosinophil chemotatic factor
neutrophil chemotatic factor
tryptase, chymase, acid hydrolase

435
Q

type 1 hypersensitivity secondary mast cell mediators

A

Platelet aggreating factor
prostaglandin D2
leukotrienes
cytokines - NF IL 1 3 4 5 6

436
Q

what is type I hypersensitivity and examples

A

Immediate IgE
anaphylaxis, allergies, asthma

437
Q

what is type II hypersensitivity and examples

A

antibody dependent
autoimmune haemolytic anaemia, erythroblastosis fotalis, rheumatic fever, goodpastures, graves disease

438
Q

what is type III hypersensitivity and examples

A

Immune complex
SLE, glomerulonephritis, Arthus reaction, serum sickness

439
Q

what is type IV hypersensitivity and examples

A

Delayed
MS, TB, contact dermatitis, T1DM, RA, IBD, graft vs host disease

440
Q

OCP is protective against

A

endometrial and ovarian cancer

Acem Primary (5 decks)

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