1- Physiology MCQs Only Flashcards

Question

25 of 192 A 28 year old man undergoes a completion right hemicolectomy for treatment of a 5cm appendiceal carcinoid. As part of his follow up he is due to undergo 24 hour urine collection for 5-HIAA. Which of the following causes an elevated 5-HIAA in a 24-hour urine collection?

Answer 1

Naproxen It is important to be aware of what can falsely elevate 5-HIAA to avoid diagnosing carcinoid syndrome incorrectly. These include: Food: spinach, cheese, wine, caffeine, tomatoes Drugs: Naproxen, Monoamine oxidase inhibitors Recent surgery

Answer 2

Severe psoriasis Lesch-Nyhan syndrome Amiodarone(Right) Diabetic ketoacidosis Alcohol ................................................ Mnemonic of the drugs causing hyperuricaemia as a result of reduced excretion of urate 'Can't leap' C iclosporin A lcohol N icotinic acid T hiazides L oop diuretics E thambutol A spirin P yrazinamide Decreased tubular secretion of urate occurs in patients with acidosis (eg, diabetic ketoacidosis, ethanol or salicylate intoxication, starvation ketosis). The organic acids that accumulate in these conditions compete with urate for tubular secretion.

Answer 3

70% Although they are small, the submandibular glands provide the bulk of salivary secretions and contribute 70%, the sublingual glands provide 5% and the remainder from the parotid. During food consumption the contribution of the parotid secretions is greater.

Answer 4

Rising haematocrit Urinary sodium <20mmol/ litre Metabolic acidosis Decreased serum urea to creatinine ratio (Right) Hypernatraemia ……………………………………. Diagnosing dehydration can be complicated, laboratory features include: Hypernatraemia Rising haematocrit Metabolic acidosis Rising lactate Increased serum urea to creatinine ratio Urinary sodium <20 mmol/litre Urine osmolality approaching 1200mosmol/kg

Answer 5

Activation of vitamin D to increase absorption of calcium from the small intestine. ............................................................ PTH increases the activity of 1-α-hydroxylase enzyme, which converts 25- hydroxycholecalciferol to 1,25-dihydroxycholecalciferol, the active form of vitamin D. Osteoclasts do not have a PTH receptor and effects are mediated via osteoblasts.

Answer 6

ß-1 Dobutamine is a sympathomimetic with both alpha- and beta-agonist properties; it displays a considerable selectivity for beta1-cardiac receptors.

Answer 7

Macrophages Fibroblasts Myofibroblasts(Right) Endothelial cells Neutrophils ................................................... Myofibroblasts are differentiated fibroblasts, in which the cytoskeleton contains actin filaments. These cell types facilitate wound contracture and are the hallmark of a mature wound. They are almost never found in wounds less than 1 month old. Remember the question asks about the cell type asks about which cells are least likely to be found.

Answer 8

Thyroid gland Calcitonin has the opposite effect of PTH and is released from the thyroid gland.

Answer 9

Less than 30 minutes Insulin is degraded by enzymes in the circulation. It typically has a half life of less than 30 minutes. Abnormalities of the clearance of insulin may occur in type 2 diabetes.

Answer 10

Histamine Remember that a low pH value indicates an acidic solution. Solutions of less than 7 (i.e. 1) have more free hydrogen ions than solutions of pH 10. Histamine is released from enterochromaffin cells in the stomach mucosa which stimulates acid secretion. It is usually released in response to increased serum gastrin levels. Histamine blockers (e.g. cimetidine) were extremely popular treatments until the advent of proton pump inhibitors.

Answer 11

Intra cranial pressure Hypoxaemia and acidosis may both affect cerebral blood flow. However, in the traumatic situation increases in intracranial pressure are far more likely to occur especially when GCS is low. This will adversely affect cerebral blood flow.

Answer 12

Blockade of neuronal sodium channels Lignocaine blocks sodium channels. They will typically be activated first, hence the pain some patients experience on administration.

Answer 13

C fibres Slow transmission of mechanothermal stimuli is transmitted via C fibres. A γ fibres transmit information relating to motor proprioception, A β fibres transmit touch and pressure and B fibres are autonomic fibres.

Answer 14

Neutrophils Neutrophil polymorphs are the cell type most commonly encountered in acute inflammation.

Answer 15

5% 70 Kg male = 42 L water (60% of total body weight)

Answer 16

Vital capacity The maximum voluntary ventilation is the maximal ventilation over the course of 1 minute.

Answer 17

Increased water permeability of the distal tubule cells of the kidney ADH (vasopressin) results in the insertion of aquaporin channels in apical membrane of the distal tubule and collecting ducts.

Answer 18

Aldosterone Aldosterone is responsible for regulating ion exchange in salivary glands. It acts on a sodium / potassium ion exchange pump.It is a mineralocorticoid hormone derived from the zona glomerulosa of the adrenal gland.

Answer 19

Zona reticularis of the adrenal gland ...................................... Adrenal cortex mnemonic: GFR - ACD DHEA possesses some androgenic activity and is almost exclusively released from the adrenal gland.

Answer 20

Duodenum Iron is best absorbed from the proximal small bowel (duodenum and jejunum) in the Fe state. Iron is transported across the small bowel mucosa by a divalent membrane transporter protein (hence the improved absorption of Fe ). The intestinal cells typically store the bound iron as ferritin. Cells requiring iron will typically then absorb the complex as needed.

Answer 21

Folic acid Pancreatic lipase is required for digestion of fat, Proteases facilitate protein and B12 absorption. Folate digestion is independent of the pancreas.

Answer 22

Vitamin C Vitamin C is needed for the hydroxylation of proline during collagen synthesis.

Answer 23

Angiotensin II Renin does not cause vasoconstriction. Angiotensin I is biologically inactive. Aldosterone will increase blood pressure but does not have direct vasospastic effects.

Answer 24

Ascending limb of the loop of Henle ..................................................... Action of furosemide = ascending limb of the loop of Henle Furosemide and bumetanide are loop diuretics that act by inhibiting the Na-K-Cl cotransporter in the thick ascending limb of the loop of Henle, reducing the absorption of NaCl.

Answer 25

pH 7.32, PCO 3.8, PaO 22.2 (FiO 40%), Bicarbonate 19.1, Base excess -7.9

Answer 26

Binding of intracellular receptors that migrate to the nucleus to then affect gene transcription Glucocorticoids exert their effects by binding intracellular receptors that are then transported to the nucleus where they affect gene transcription. There are some questions in the MRCS now that seem to test common pharmacology and so we have decided to include this. A detailed knowledge of the mechanisms by which these effects occur is not needed.

Answer 27

Vitamin c Zinc Vitamin B12(Right) Copper Molybdenum ....................................... Vitamin B12. The others are unaffected

Answer 28

The intrinsic pathway is the main pathway in coagulation Heparin inhibits the activation of Factor 8 The activation of factor 8 is the point when the intrinsic and the extrinsic pathways meet Tissue factor released by damaged tissue initiates the extrinsic pathway(Right) Thrombin converts plasminogen to plasmin .............................................. The extrinsic pathway is the main path of coagulation. Heparin inhibits the activation of factors 2,9,10,11. The activation of factor 10 is when both pathways meet. Thrombin converts fibrinogen to fibrin. During fibrinolysis plasminogen is converted to plasmin to break down fibrin.

Answer 29

76 mmHg Cerebral perfusion pressure= Mean arterial pressure - intra cranial pressure The mean arterial pressure can be calculated as: MAP= Diastolic pressure+ 0.333(Systolic pressure- Diastolic pressure) In this situation the MAP = 93. The ICP is subtracted from this value; 93 - 17 = 76

Answer 30

During a Valsalva manoeuvre During a Valsalva manoeuvre, the intra pleural pressure rises owing to extrinsic compression.

Answer 31

pH 7.19, pCO 10.2, pO 16 (FiO 85%), Bicarbonate 23.8, Base excess -2.2 mmol

Answer 32

Metabolic alkalosis This would be a typical result of prolonged vomiting.

Answer 33

Acetyl choline In the autonomic nervous system, noradrenaline is the commonly used neurotransmitter. However, in the adrenal medulla, Acetylcholine is released to stimulate adrenaline release.

Answer 34

Absent a waves Jugular venous pressure Absent a waves = Atrial fibrillation Large a waves = Any cause of right ventricular hypertrophy, tricuspid stenosis Cannon waves (extra large a waves) = Complete heart block Prominent v waves = Tricuspid regurgitation Slow y descent = Tricuspid stenosis, right atrial myxoma Steep y descent = Right ventricular failure, constrictive pericarditis, tricuspid regurgitation This patient has atrial fibrillation and is most likely to have absent a waves.

Answer 35

It has a pressure of between 10 and 15 mmHg. It usually contains a small amount of glucose. It may normally contain up to 5 red blood cells per mm .(Right) It may normally contain up to 3 white blood cells per mm . None of the above ...................................................... It should not contain red blood cells.

Answer 36

It stimulates pancreatic acinar cells to release lipase(Right) It decreases gastric acid secretion It decreases gastrin release It decreases pepsin secretion It decreases glucagon release ................................................ It inhibits pancreatic enzyme secretion.

Answer 37

Hydrochloric acid Mucus (Right) Magnesium Intrinsic factor Calcium ……………………………….. Chief of Pepsi cola = Chief cells secrete PEPSInogen Parietal cells: secrete HCl, Ca, Na, Mg and intrinsic factor Chief cells: secrete pepsinogen Surface mucosal cells: secrete mucus and bicarbonate

Answer 38

Rapid sodium influx

Answer 39

Macrophages

Answer 40

Carotid sinus and aortic arch

Answer 41

Tyrosine Catecholamine hormones are derived from tyrosine, it is modified by a DOPA decarboxylase enzyme to become dopamine and thereafter via two further enzymic modifications to noradrenaline and finally adrenaline.

Answer 42

In restrictive lung disease the FEV1/FVC ratio is increased Residual volume is increased in emphysema Functional residual capacity is measured by helium dilution test The tidal volume is approximately 340mls in females The vital capacity is increased in Guillain Barre syndrome(Right) ......................................................... FEV1/FVC is normal or >80% in restrictive lung disease such as pulmonary fibrosis. The ratio is reduced in obstructive airways disease. The functional residual capacity, residual volume and the total lung capacity cannot be measured with spirometry. They can only be measured by helium dilution. The vital capacity is reduced in: 1. Pulmonary fibrosis/infiltration/oedema/effusions 2. Weak respiratory muscles e.g. MG, GBS, myopathies 3. Skeletal abnormalities e.g. chest wall abnormalities

Answer 43

Platelet degranulation Many of these events contribute to healing. However, platelet degranulation is the earliest phase and results in haemostasis, the main event in then allowing the release of cytokines to attract other cells types to the wound and co-ordinate healing.

Answer 44

α 1 receptors Noradrenaline is the precursor of adrenaline. It is a powerful α 1 stimulant (although it will increase myocardial contractility). Infusions will produce vasoconstriction and an increase in total peripheral resistance. It is the inotrope of choice in septic shock.

Answer 45

Distal convoluted tubule

Answer 46

His haemoglobin will have decreased affinity for oxygen The process of starvation may lower DPG levels, in practice this is unlikely to occur early as it is generated during glycolysis. Altered metabolism in starvation may be more acidotic and this would also tend to impair oxygen carriage.

Answer 47

It may occur as a result of mechanical bowel preparation Chronic vomiting may increase renal potassium losses It may be associated with aciduria It may cause hyponatraemia It often accompanies acidosis(Right) ..................................................................... Potassium depletion occurs either through the gastrointestinal tract or the kidney. Chronic vomiting in itself is less prone to induce potassium loss than diarrhoea as gastric secretions contain less potassium than those in the lower GI tract. If vomiting produces a metabolic alkalosis then renal potassium wasting may occur as potassium is excreted in preference to hydrogen ions. The converse may occur in potassium depletion resulting in acid urine. Hypokalemia is very commonly associated with metabolic alkalosis. This is due to 2 factors: 1) the common causes of metabolic alkalosis (vomiting, diuretics) directly induce H+ and K loss (via aldosterone) and thus also cause hypokalemia and 2) hypokalemia is a very important cause of metabolic alkalosis by three mechanisms. The initial effect is by causing a transcellular shift in which K leaves and H+ enters the cells, thereby raising the extracellular pH. The second effect is by causing a transcellular shift in the cells of the proximal tubules resulting in an intracellular acidosis, which promotes ammonium production and excretion. Thirdly, in the presence of hypokalemia, hydrogen secretion in the proximal and distal tubules increases. This leads to further reabsorption of HCO3-. The net effect is an increase in the net acid excretion.

Answer 48

Increased cardiac output Increased systemic vascular resistance(Right) Oliguria may occur Systemic cytokine release Tachycardia ...................................................... Cardiogenic Shock: e.g. MI, valve abnormality increased SVR (vasoconstriction in response to low BP) increased HR (sympathetic response) decreased cardiac output decreased blood pressure Hypovolaemic shock: blood volume depletion e.g. haemorrhage, vomiting, diarrhoea, dehydration, third-space losses during major operations increased SVR increased HR decreased cardiac output decreased blood pressure Septic shock: occurs when the peripheral vascular dilatation causes a fall in SVR similar response may occur in anaphylactic shock, neurogenic shock reduced SVR increased HR normal/increased cardiac output decreased blood pressure The SVR is reduced in sepsis and for this reason a vasopressor such as noradrenaline may be used if hypotension and oliguria remain a concern despite administration of adequate amounts of intravenous fluids.

Answer 49

Hartmans Hartmans solution is the most electrolyte rich. However, both pentastarch and gelofusine have more macromolecules.

Answer 50

Deficiency of ascorbic acid Vitamin C is involved in the cross linkage of collagen and impaired wound healing is well described in cases of vitamin C deficiency.

Answer 51

He will have more water per unit of body weight than a female of similar weight Plasma will comprise 25% of his body weight(Right) Interstitial fluid will account for up to 24% of body water Approximately 65% of total body water is intracellular 60% of his body weight is composed of water ...................................................................... The 60-40-20 rule: 60% total body weight is water 40% of total body weight is intracellular fluids 20% of body weight is extracellular fluids Plasma typically accounts for 4-6% of body weight in healthy individuals. Males typically have more water per unit weight than females, as females have a higher fat content.

Answer 52

Vitamin A Loss of vitamin A will result in impair rhodopsin synthesis and results in poor night vision.

Answer 53

Packed red cells typically have a haematocrit of between 55 and 75% Clotting factor activity in whole blood decreases in samples stored for longer than 7 days After 3 weeks of storage blood has a pH of 6.9 Gamma irradiated blood products are not required routinely Patients should be transfused to achieve a target haemoglobin of 10 g/dl and a haematocrit of 30%(Right) ……………………………………………….. Patients can generally be managed without transfusion as long as the Hb is 7 or greater. The exact level depends upon patient factors such as co-morbidities. Old blood functions less effectively and should not be used during massive transfusions.

Answer 54

Release from the adrenal medulla in response to sympathetic stimulation from the splanchnic nerves The adrenal gland releases adrenaline in response to increased sympathetic discharge from preganglionic sympathetic fibres of the splanchnic nerves. These cause the chromafin cells of the medulla to release adrenaline (which is preformed) by exocytosis.

Answer 55

Pyrexia Decreased albumin Hepatic sequestration of cations Increased transferrin(Right) Increased serum amyloid A ......................................................... The acute phase response includes: Acute phase proteins Reduction of transport proteins (albumin, transferrin) Hepatic sequestration cations Pyrexia Neutrophil leucocytosis Increased muscle proteolysis Changes in vascular permeability

Answer 56

Prothrombin time' PT: Vitamin K dependent factors 2, 7, 9, 10 APTT: Factors 8, 9, 11, 12 Jaundice will impair the production of vitamin K dependent clotting factors. This is most accurately tested by measuring the prothrombin time. APTT can be affected by vitamin K deficiency (due to factor 9 deficiency), however this occurs to a lesser extent and is normally associated with severe liver disease. The bleeding time is a measure of platelet function.

Answer 57

Secretin Secretin causes secretion of water and electrolytes Cholecystokinin causes enzyme secretion While secretin will typically increase electrolyte and water volume of secretions, the enzyme content is increased by cholecystokinin. Somatostatin will decrease the volume of secretions. Aldosterone will tend to conserve electrolytes.

Answer 58

Zona glomerulosa of the adrenal cortex Aldosterone serves to conserve sodium and water. It is produced in the zona glomerulosa of the adrenal cortex.

Answer 59

Nausea Nausea inhibits gastric secretion via higher cerebral activity and sympathetic innervation.

Answer 60

Reduction in ionised calcium levels 50% of plasma calcium is ionised. Hyperventilation will induce a state of alkalosis which will lower ionised plasma calcium levels.

Answer 61

In parietal cells carbonic anhydrase generates hydrogen ions which are then actively secreted The cephalic phase is abolished following truncal vagotomy The intestinal phase accounts for 60% of gastric acid produced(Right) Histamine acts in a paracrine manner on H receptors H receptor antagonists will not completely abolish gastric acid production ............................................................... The intestinal phase of gastric acid secretion accounts for only 10% of gastric acid produced.

Answer 62

Body temperature less than 36 C or greater than 38 C Respiratory rate >20 Lactate <4 mmol/L(Right) High levels of tumour necrosis factor α WCC >12,000 mm3 ................................................... Septic shock will typically result in end organ hypoperfusion and as a result lactate levels will often be high. In the surviving sepsis campaign it is suggested that elevated lactate levels are an independent indicator for vasopressor support in patient with sepsis. The WCC may be paradoxically low in severe sepsis, although it is most often elevated.

Answer 63

Histamine .......................................... Gastrin: From G cells: stimulates gastric acid production Pepsin: Digestion of protein, secretion occurs simultaneously with gastrin Secretin: From mucosal cells in the duodenum and jejunum: inhibits gastric acid, stimulates bile and pancreatic juice production Gastric inhibitory peptide: (produced in response to fatty acids) inhibits gastrin release and acid secretion from parietal cells Cholecystokinin: From mucosal cells in the duodenum and jejunum (produced in response to fatty acids) inhibits acid secretion from parietal cells, causes gallbladder contraction and relaxation of sphincter of Oddi Somatostatin: From D cells

Answer 64

Decrease in pancreatic exocrine secretions Octreotide reduces exocrine pancreatic secretions so is used to treat high output pancreatic fistulae (though parenteral feeding is most effective). Other uses include variceal bleeding and treatment of acromegaly. Inhibits growth hormone and insulin release (when released from pancreas). Somatostatin is also released by the hypothalamus causing a negative feedback response on growth hormone.

Answer 65

Thiazides Antacids Coeliac disease(Right) Sarcoidosis Zolinger-Ellison syndrome ........................................................... Mnemonic for the causes of hypercalcaemia: CHIMPANZEES C alcium supplementation H yperparathyroidism I atrogentic (Drugs: Thiazides) M ilk Alkali syndrome P aget disease of the bone A cromegaly and Addison's Disease N eoplasia Z olinger-Ellison Syndrome (MEN Type I) E xcessive Vitamin D E xcessive Vitamin A S arcoidosis Patients with coeliac disease tend to develop hypocalcaemia due to malabsorption of calcium by the bowel.

Answer 66

Pancreatic fistula Acetazolamide Uraemia(Right) Ureteric diversion Renal tubular acidosis ……………………………………………….. Normal Gap Acidosis: HARDUP H - Hyperalimentation/hyperventilation A - Acetazolamide R - Renal tubular acidosis D - Diarrhoea U - Ureteral diversion P - Pancreatic fistula/parenteral saline Uraemia will typically cause a high anion gap acidosis. It is one of the unmeasured anions.

Answer 67

Pulmonary haemorrhage Transfer factor raised: asthma, haemorrhage, left-to-right shunts, polycythaemia low: everything else Where alveolar haemorrhage occurs the TLCO tends to increase due to the enhanced uptake of carbon monoxide by intra-alveolar haemoglobin.

Answer 68

Residing at 4500M for 48 hours The patient has low oxygen tension and low carbon dioxide. The pH is normal so there is compensation for a long standing condition in which oxygenation is reduced. There is neither alkalosis, nor hypoventilation as the carbon dioxide is low. At very high altitude, the low oxygen tension can exceed the anaerobic threshold and carbon dioxide levels increase.

Answer 69

Up to 95% of filtered amino acids will be reabsorbed at this site It is a risk of damage in a patient with compartment syndrome due to a tibial fracture It is responsible for absorbing more than 50% of filtered water Its secretory function is most effective at low systolic blood pressures (typically less than 100mmHg)(Right) Glucose is reabsorbed by a process of facilitated diffusion ……………………………………… The proximal convoluted tubule may undergo necrosis in situations such as compartment syndrome. It is responsible for reabsorbing up to two thirds of filtered water. Low systolic blood pressures (below the renal autoregulatory range) are a risk factor for acute tubular necrosis. Within the autoregulatory range the absolute value of systolic BP has little effect.

Answer 70

500 mL Between 500 mL and 1.5 L of bile enters the small bowel daily. Most bile salts are recycled by the enterohepatic circulation. When the gallbladder contracts the lumenal pressure is approximately 25cm water, which is why biliary colic may be so painful.

Answer 71

Jejunum Water absorption in the gastrointestinal tract predominantly occurs in the small bowel (jejunum and ileum). The colon is an important site of water absorption, however, its overall contribution is relatively small. The importance of the colonic component to water absorption may increase following extensive small bowel resections.

Answer 72

Hyperkalaemia In this scenario the patient will have a compartment syndrome, delayed diagnosis and muscle death. The effect of muscle death will result in the release of potassium. It is also highly likely that there will be a degree of renal impairment, the result of which is that the serum potassium is likely to be high.

Answer 73

<15mm Hg The normal intracranial pressure is between 7 and 15 mm Hg. The brain can accommodate increases up to 24 mm Hg, thereafter clinical features will become evident.

Answer 74

Carbamazepine SIADH - drug causes: carbamazepine, sulfonylureas, SSRIs, tricyclics Lithium can cause diabetes insipidus but this is generally associated with a high sodium. Lithium only tends to cause raised antidiuretic hormone levels following a severe overdosage.

Answer 75

Inulin Creatinine declines with age due to decline in renal function and muscle mass. Glucose, protein (amino acids) and PAH are reabsorbed by the kidney.

Answer 76

The choroid plexus is only present in the lateral ventricles(Right) Total CSF volume is 100-150ml CSF pressure is usually 10-15mmHg The cerebral aqueduct connects the third and fourth ventricles The foramen of Luschka are paired and lie laterally in the fourth ventricle ................................................ The choroid plexus lies in all ventricles.

Answer 77

Hypotonic hypovolaemic hyponatraemia The blood results reflect extra-renal sodium loss. The body is trying to preserve the sodium by not allowing any sodium into the urine (hence the low Na in the urine). Note with renal sodium loss the Urinary sodium is high.

Answer 78

Flow volume loop Flow volume loop is the investigation of choice for upper airway compression.

Answer 79

Rifampicin Quinine Noradrenaline(Right) Levodopa Phenytoin ........................................................... Rifampicin, phenytoin, levodopa, methyldopa, and quinine all cause pseudohaematuria.

Answer 80

Hypertension and bradycardia Hypertension and bradycardia are seen prior to coning. The brain autoregulates its blood supply by controlling systemic blood pressure.

Answer 81

Magnesium Patients with malabsorption may develop magnesium deficiency, although her TPN feeds may have contained magnesium it may not have been sufficient to correct her losses. Sodium, phosphate and potassium would not have this effect on serum calcium.

Answer 82

Dexamethasone(Right) Prednisolone Hydrocortisone IV Hydrocortisone PO Hydrocortisone IM ...................................................... Prednisolone and it's metabolites can chemically mimic cortisol in radio- immunoassay techniques of laboratory analysis. Dexamethasone can be given as glucorticoid replacement during testing for addisons or adrenal insufficiency as it does not interfere with cortisol levels. For example, if you have a patient with polymyalgia rheumatica and they are on long term prednisolone, you can replace the prednisolone with dexamethasone to undertake a short synacthen test.

Answer 83

Lipase Loss of lipase is one of the key features in the development of steatorrhoea which typically consists of pale and offensive stools that are difficult to flush away.

Answer 84

Thyroid stimulating hormone TSH release is inhibited by negative feedback.

Answer 85

Hypothalamus The hypothalamus is primarily concerned with thermoregulation. It may relay to the cerebral cortex to induce behavioural adaptation to facilitate the thermoregulatory process.

Answer 86

Iron reutilisation Storage of platelets Storage of monocytes Haematopoeisis in haematological disorders Storage red blood cells(Right) ................................................... The reservoir function of the spleen is less marked in humans than other animals (e.g. pigs) and in normal individuals it can sequester between 5 and 10% of the red cell mass. The other stated processes are major splenic functions and this accounts for the answer provided.

Answer 87

Insulin(Right) ACTH Glucocorticoids Aldosterone Growth hormone .................................................. Insulin and thyroxine are often have reduced levels of secretion in the post operative period. This, coupled with increased glucocorticoid release may cause difficulty in management of diabetes in individuals with insulin resistance.

Answer 88

Beta-blockers

Answer 89

Thyrotropin releasing hormone TRH stimulates prolactin release. Dopamine suppresses the release of prolactin.

Answer 90

Binding to μ opioid receptors within the CNS 4 Types of opioid receptor: δ (located in CNS)- Accounts for analgesic and antidepressant effects k (mainly CNS)- analgesic and dissociative effects μ (central and peripheral) - causes analgesia, miosis, decreased gut motility Nociceptin receptor (CNS)- Affect of appetite and tolerance to μ agonists.

Answer 91

Type II respiratory failure This is a sign of acute type 2 respiratory failure (non compensated). This is the result of carbon dioxide retention.

Answer 92

With decreased 2,3-DPG in transfused red cells ................................................... S shaped curve The curve is shifted to the left when there is a decreased oxygen requirement by the tissue. This includes: 1. Hypothermia 2. Alkalosis 3. Reduced levels of DPG: DPG is found in erythrocytes and is reduced in non exercising muscles, i.e. when there is reduced glycolysis. 4. Polycythaemia

Answer 93

Pseudohyponatraemia Hyperlipidaemia and multiple myeloma are known to cause a pseudohyponatraemia, this is due to raised protein.

Answer 94

Wernickes encephalopathy Triad of Wernicke encephalopathy: Acute confusion Ataxia Ophthalmoplegia This patient has received a carbohydrate rich diet without any thiamine or vitamin B co strong replacement. This has led to Wernickes encephalopathy, which classically presents with confusion, ataxia and ophthalmoplegia. Characteristically it is associated with chronic alcoholism, however it is also known to occur post bariatric surgery.

Answer 95

Ferritin Ferritin can be markedly increased during acute illness. The other parameters tend to decrease during an acute phase response.

Answer 96

wave T wave Q-T Interval P-R interval None of the above(Right) …………………………………………. The process of atrial repolarisation is generally not visible on the ECG strip. It occurs during the QRS complex.

Answer 97

U waves ………………………… Hypokalaemia - U waves on ECG J waves are seen in hypothermia whilst delta waves are associated with Wolff Parkinson White syndrome.

Answer 98

It causes gallbladder contraction It increases the rate of gastric emptying(Right) It relaxes the sphincter of oddi It stimulates pancreatic acinar cells It has a trophic effect on pancreatic acinar cells ....................................................... it decreases the rate of gastric emptying.

Answer 99

No response to intravenous fluids In acute tubular necrosis there is no response to intravenous fluids because the damage occurs from within the renal system rather than as a result of volume depletion.

Answer 100

c wave JVP: C wave - closure of the tricuspid valve The c wave of the jugular venous waveform is associated with the closure of the tricuspid valve.

Answer 101

Longitudinal smooth muscle propels the food bolus through the oesophagus(Right) Secondary peristalsis occurs when there is no food bolus in the oesophagus Food transfer from the oesophagus to the stomach is 4 seconds Circular smooth muscle is not involved in peristalsis Peristalsis only occurs in the oesophagus ..........................................

Answer 102

Thyroglobulin It is a high molecular weight protein that acts as a storage form of thyroid hormones.

Answer 103

Osteonecrosis Osteoporosis Hypokalaemia Hyponatraemia(Right) Growth retardation in children …………………………………….. There are many adverse effects associated with excess glucocorticoids. Thinning of the skin, osteonecrosis and osteoporosis are all common. Steroids are associated with retention of sodium and water. Potassium loss may occur and hypokalaemic alkalosis has been reported.

Answer 104

End diastolic volume Preload is the same as end diastolic volume. When it is increased slightly there is an associated increase in cardiac output (Frank Starling principle). When it is markedly increased e.g. over 250ml then cardiac output falls.

Answer 105

Cholestatic jaundice Disseminated intravascular coagulation Prolonged antibiotic treatment Liver disease Acquired factor 12 deficiency (Right) ……………………………………… Vitamin K deficiency results from cholestatic jaundice and prolonged antibiotic therapy. Acquired factor 12 deficiency causes prolonged APTT.

Answer 106

von Willebrands disease Bleeding post operatively, epistaxis and menorrhagia may indicate a diagnosis of vWD. Haemoarthroses are rare. The bleeding time is usually normal in haemophilia (X-linked) and vitamin K deficiency.

Answer 107

Locally perforated sigmoid colonic adenocarcinoma A locally perforated colonic tumour will typically cause an intense inflammatory response and if peritonitis is not present clinically then at the very least a localised abscess. This inflammatory process is the most likely (from the list) to falsely raise the serum ferritin level. Angiodysplasia and dieulafoy lesions are mucosal arteriovenous malformations and unlikely to result in considerable inflammatory activity.

Answer 108

Glycogenolysis Increased production of acute phase proteins Increased cortisol production Bronchoconstriction(Right) Release of nitric oxide by vessels

Answer 109

2 The intragastric pH is usually 2. Administration of proton pump inhibitors can result in almost complete abolition of acidity

Answer 110

Heparin Both unfractionated and low-molecular weight heparin can cause hyperkalaemia. This is thought to be caused by inhibition of aldosterone secretion. Salbutamol is a recognised treatment for hyperkalaemia.

Answer 111

Ghrelin Obesity hormones leptin decreases appetite ghrelin increases appetite Whilst thyroxine can increase appetite it does not fit with the clinical picture being described.

Answer 112

Renin The decrease in blood pressure will be sensed by the juxtaglomerular cells in the kidney. This will cause renin secretion.

Answer 113

In a healthy 70Kg male, the glomerular filtration rate will be the same at a systolic blood pressure of 120mmHg as a systolic blood pressure of 95 mmHg Over 90% of the blood supply to the kidney is distributed to the cortex The kidney receives approximately 25% of the total cardiac output at rest A decrease in renal perfusion pressure will cause the juxtaglomerular cells to secrete renin Systolic blood pressures of less than 65mmHg will cause the mesangial cells to secrete aldosterone(Right) ………………………………………………… The kidney autoregulates its blood supply over a range of systolic blood pressures. Drop in arterial pressure is sensed by the juxtaglomerular cells and renin is released leading to the activation of the renin-angiontensin system. Mesangial cells are contractile cells that are located in the tubule and have no direct endocrine function.

Answer 114

Thyrotoxicosis Diuretics increase the risk of re-feeding syndrome through a process of increasing the risk of depletion of key electrolytes.

Answer 115

Parietal cells Parietal cells are responsible for the release of gastric acid. Brunners glands are found in the duodenum.

Answer 116

Coronary artery vasospasm It's cardiac effects are mediated via β 1 receptors. The coronary arteries which have β 2 receptors are unaffected.

Answer 117

A 2 month old child(Right) A 2 year old child A 5 year old child A 10 year old child An adult ............................................. The Monroe-Kelly Doctrine assumes that the cranial cavity is a rigid box. In children with non fused fontanells this is not the case.

Answer 118

Pancreatic polypeptide Glucagon Secretin(Right) Somatostatin Insulin .................................. Secretin is released from mucosal cells in the duodenum and jejunum.

Answer 119

Haemolysis Burns Familial periodic paralysis Type 4 renal tubular acidosis Severe malnutrition(Right) ………………………………………….. 'Machine' - Causes of Increased Serum K M - Medications - ACE inhibitors, NSAIDS A - Acidosis - Metabolic and respiratory C - Cellular destruction - Burns, traumatic injury H - Hypoaldosteronism, haemolysis I - Intake - Excessive N - Nephrons, renal failure E - Excretion - Impaired Familial periodic paralysis has subtypes associated with hyper and hypokalaemia.

Answer 120

Cholecystokinin Cholecystokinin will often increase the volume of pancreatic secretions.

Answer 121

Metoclopramide(Right) Botulinum toxin type A Nicotine Alcohol Theophylline ……………………………………….. Metoclopramide acts directly on the smooth muscle of the LOS to cause it to contract. Theophylline is a phosphodiesterase inhibitor (mimics action of prostaglandin E1) which causes relaxation of the LOS.

Answer 122

mu Pethidine and other conventional opioids attach to this receptor.

Answer 123

10 minutes PTH has a very short half life usually less than 10 minutes. Therefore a demonstrable drop in serum PTH should be identified within 10 minutes of removing the adenoma. This is useful clinically since it is possible to check the serum PTH intraoperatively prior to skin closure and explore the other glands if levels fail to fall.

Answer 124

Adrenaline Inhibition of insulin release: Alpha adrenergic drugs Beta blockers Sympathetic nerves

Answer 125

Haemoglobin Approximately 70% of body iron is found bound to haemoglobin.

Answer 126

Uraemia Paraldehyde Diabetic ketoacidosis Ethylene glycol Acetazolamide(Right) ........................................................ Causes of increased anion acidosis: MUDPILES M - Methanol U - Uraemia D - DKA/AKA P - Paraldehyde/phenformin I - Iron/INH L - Lactic acidosis E - Ethylene glycol S - Salicylates

Answer 127

Sex hormones

Answer 128

Platelet adhesion to disrupted endothelium is dependent upon von Willebrand factor Protein C is a vitamin K dependent substance The bleeding time provides an assessment of platelet function The prothrombin time tests the extrinsic system Administration of aprotinin during liver transplantation surgery prolongs survival(Right) ………………………………………………………… Although aprotinin reduces fibrinolysis and thus bleeding, it is associated with increased risk of death and was withdrawn in 2007. Protein C is dependent upon vitamin K and this may paradoxically increase the risk of thrombosis during the early phases of warfarin treatment.

Answer 129

23 mmol/L The anion gap may be calculated by using (sodium + potassium) - (bicarbonate + chloride) = (142 + 4.0) - (104 + 19) = 23 mmol/L

Answer 130

Cerebral vasodilation Hypercapnia will tend to produce cerebral vasodilation. This is of considerable importance in patients with cranial trauma as it may increase intracranial pressure.

Answer 131

pH 7.20, pO 9.0, pCO 3.5, Base excess -10, Lactate 8 This man is likely to have a metabolic acidosis secondary to a mesenteric infarct.

Answer 132

Erythrocyte Erythrocytes lack a mitochondria and therefore they generate energy via glycolytic pathways only. All the other cell types have mitochondria and will therefore use the Krebs cycle unless true anaerobic conditions prevail.

Answer 133

Gelofusine Dextran 40 Human albumin solution Hydroxyethyl starch Bicarbonate 8.4%(Right) .......................................................... Bicarbonate is a crystalloid.

Answer 134

Zona fasciculata of the adrenal(Right) Zona glomerulosa of the adrenal Zona reticularis of the adrenal Adrenal medulla Posterior lobe of the pituitary ................................................ Relative Glucocorticoid activity: Hydrocortisone = 1 Prednisolone = 4 Dexamethasone = 25 Cortisol is produced by the zona fasciculata of the adrenal gland.

Answer 135

Factor VIII Factors V and VIII are sensitive to temperature which is the reason why FFP is frozen soon after collection.

Answer 136

Vitamin K Patients who are jaundiced usually have impaired absorption of vitamin K. This can result in loss of the vitamin K dependent clotting factors and troublesome bleeding.

Answer 137

Inhibition of plasmin Tranexamic acid inhibits plasmin and this prevents fibrin degradation.

Answer 138

Administration of intravenous calcium gluconate Exploration of the parathyroid glands may result in impairment of the blood supply. Serum PTH levels can fall quickly and features of hypocalcaemia may ensue, these include neuromuscular irritability and laryngospasm. Prompt administration of intravenous calcium gluconate can be lifesaving. The absence of any neck swelling and no blood in the drain would go against a contained haematoma in the neck (which should be managed by removal of skin closure).

Answer 139

1500ml Typically the pancreas secretes between 1000 and 1500ml per day.

Answer 140

Cardiac output Renin secretion(Right) Firing of carotid baroreceptors Firing of aortic baroreceptors Blood pressure ............................................................. Renin secretion will increase as systemic hypotension will cause impairment of renal blood flow. Although the kidney can autoregulate its own blood flow over a range of systemic blood pressures a loss of 1.6 L will usually produce an increase in renin secretion.

Answer 141

70ml Stroke volumes range from 55-100ml.

Answer 142

Rectum The rectum has the potential to generate secretions rich in potassium. This is the rationale behind administration of resins for hyperkalaemia and the development of hypokalaemia in patients with villous adenoma of the rectum.

Answer 143

Activation of the renin angiotensin system The loss of 500ml (assuming a 70 Kg male) will usually be sufficient to activate the renin angiotensin system. It is unlikely that it would cause any other physiological disturbance.

Answer 144

Obesity Pulmonary fibrosis Muscle relaxants Laparoscopic surgery Upright position(Right) ......................................... Increased FRC: Erect position Emphysema Asthma Decreased FRC: Pulmonary fibrosis Laparoscopic surgery Obesity Abdominal swelling Muscle relaxants When the patient is upright the diaphragm and abdominal organs put less pressure on the lung bases, allowing for an increase in the functional residual capacity (FRC). Other causes of increased FRC include: Emphysema Asthma In addition to those listed above, causes of reduced FRC include: Abdominal swelling Pulmonary oedema Reduced muscle tone of the diaphragm Age

Answer 145

Decreased cardiac output Increased heart rate Reduced left ventricle filling pressures Reduced blood pressure Reduced systemic vascular resistance(Right) ......................................................................... Cardiogenic Shock: e.g. MI, valve abnormality increased SVR (vasoconstriction in response to low BP) increased HR (sympathetic response) decreased cardiac output decreased blood pressure Hypovolaemic shock: blood volume depletion e.g. haemorrhage, vomiting, diarrhoea, dehydration, third-space losses during major operations increased SVR increased HR decreased cardiac output decreased blood pressure Septic shock: occurs when the peripheral vascular dilatation causes a fall in SVR similar response may occur in anaphylactic shock, neurogenic shock reduced SVR increased HR normal/increased cardiac output decreased blood pressure SVR will typically increase

Answer 146

Gastrin Atenolol(Right) Protein Secretin Vagal cholinergic action .............................................. Beta blockers inhibit the release of insulin.

Answer 147

110ml / minute The proposed drop in blood pressure falls within the range within which the kidney autoregulates its blood supply. GFR will therefore remain unchanged.

Answer 148

Medullary respiratory centre Opiates typically affect the medullary respiratory centre to depress respiratory activity.

Answer 149

Angiotensinogen Renin hydrolyses angiotensinogen to form angiotensin I.

Answer 150

Alveolar ventilation is increased. Anatomical dead space is reduced by 50%. Work of breathing is increased.(Right) Proportion of ciliated epithelial cells in the trachea may decrease. Splinting of the larynx may lead to swallowing difficulties. .................................................................. Work of breathing is decreased which is one of the reasons it is a popular option for weaning ventilated patients. Humidified air in this setting helps to reduce the viscosity of mucous that forms.

Answer 151

120 mmol Investigators in the 1960's dehydrated and measured the sodium content of ileostomy effluent and determined this concentration. Not an experiment many would care to repeat!

Answer 152

Chronic iron deficiency anaemia .................................................................. Mnemonic to remember causes of right shift of the oxygen dissociation curve: CADET face RIGHT C O2 A cidosis 2,3-DPG E xercise T emperature The curve is shifted to the right when there is an increased oxygen requirement by the tissue. This includes: Increased temperature Acidosis Increased DPG: DPG is found in erythrocytes and is increased during glycolysis. It binds to the Hb molecule, thereby releasing oxygen to tissues. DPG is increased in conditions associated with poor oxygen delivery to tissues, such as anaemia and high altitude.

Answer 153

T wave The T wave represents ventricular repolarization. The common sense approach to remembering this, is to acknowledge that ventricular repolarization is the last phase of cardiac contraction and should therefore correspond the the last part of the QRS complex.

Answer 154

IV Pamidronate IV Pamidronate is the drug of choice as it most effective and has long lasting effects. Calcitonin would need to be given with another agent, to ensure that the hypercalcaemia is treated once its short term effects wear off. IV zoledronate is preferred in scenarios associated with malignancy.

Answer 155

Respiratory alkalosis The hyperventilation results in decreased carbon dioxide levels, causing a respiratory alkalosis (non compensated).

Answer 156

Stimulation of Mu receptors 4 Types of opioid receptor: δ (located in CNS)- Accounts for analgesic and antidepressant effects k (mainly CNS)- analgesic and dissociative effects μ (central and peripheral) - causes analgesia, miosis, decreased gut motility Nociceptin receptor (CNS)- Affect of appetite and tolerance to μ agonists. Constipation is a common side effect of morphine treatment and stimulation of Mu receptors accounts for this process.

Answer 157

Oral cholestyramine The question is about high output diarrhoea following terminal ileal resection and the most likely cause is malabsorption of bile salts. The administration of cholestyramine (bile salt binding agent) will counter this and thats why its the correct answer. Malabsorption of bile salts is a common cause of diarrhoea following ileal resection. A normal small bowel study and CRP effectively excludes active Crohns disease and therefore immunomodulator drugs are not appropriate.

Answer 158

Endothelial cell proliferation Angiogenesis is a key event in wound healing and occurs as a result of endothelial cell proliferation.

Answer 159

Insulin Endocrine parameters reduced in stress response: Insulin Testosterone Oestrogen Insulin is often released in decreased quantities following surgery.

Answer 160

Increased specific gravity Hypovolaemic shock is likely to compromise renal blood flow especially if blood pressure falls below the range at which the kidney is able to autoregulate its blood flow. The result of this will be an increase of the specific gravity as water retention occurs in an attempt to maintain circulating volume.

Answer 161

Emptying of the right atrium JVP 3 Upward deflections and 2 downward deflections Upward deflections a wave = atrial contraction c wave = ventricular contraction v wave = atrial venous filling Downward deflections x wave = atrium relaxes and tricuspid valve moves down y wave = ventricular filling The y descent represents the emptying of the atrium and the filling of the right ventricle.

Answer 162

Factor V Factor VII Factor IX Factor VIII(Right) Factor XI ....................................................... Factor VIII is synthesised in the endothelial cells of the liver rather than the liver itself and therefore is less prone to the effects of hepatic dysfunction.

Answer 163

Vitamin D Vitamin D is needed to help mineralise bone. When this is deficient, mineralisation is inadequate and deformities may result.

Answer 164

Factor VIII .................................................... vWF stabilizes factor VIII If you answered this incorrectly check you did not select factor VII by mistake!

Answer 165

P wave The P wave represents atrial depolarization. Note that atrial repolarization is obscured within the QRS complex.

Answer 166

Erythromycin Vagotomy seriously compromises gastric emptying which is why either a pyloroplasty or gastro-enterostomy is routinely performed at the same time. Chloramphenicol has no effect on gastric emptying. Ondansetron slows gastric emptying slightly. Metoclopramide increases the rate of gastric emptying but its effects are mediated via the vagus nerve. Erythromycin enhances gastric emptying by acting via the motilin receptor in the gut.