PHYSIO 4 Flashcards
Which of the following statements relating to cerebrospinal fluid is untrue?
The choroid plexus is only present in the lateral ventricles 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 is only present in the lateral ventricles
The choroid plexus lies in all ventricles.
Which substance can be used to achieve the most accurate measurement of the glomerular filtration rate?
Glucose Protein Inulin Creatinine Para-amino hippuric acid
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.
A 45 year old man sustains a closed head injury. He is initially alert, however, his level of consciousness deteriorates on arrival at hospital. An intra cranial pressure monitor is inserted. What is the normal intracranial pressure?
35 - 45mm Hg 45 - 55mm Hg <15mm Hg 25 - 35mm Hg 25 - 30 mm Hg
<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.
A 55-year-old man with a history of type 2 diabetes mellitus, bipolar disorder and chronic obstructive pulmonary disease has bloods taken during a pre operative assessment of an inguinal hernia repair:
Na+ 125 mmol/l K+ 3.8 mmol/l Bicarbonate 24 mmol/l Urea 3.7 mmol/l Creatinine 92 µmol/l
Due to his smoking history a chest x-ray is ordered which is reported as normal. The Consultant asks you what is the most likely cause for the hyponatraemia?
Metformin Lithium Carbamazepine Sodium valproate Pioglitazone
Carbamazepine
Lithium can cause diabetes insipidus but this is generally associated with a high sodium.
A 24 year old man is involved in a road traffic accident. His right leg is trapped for 6 hours whilst he is moved. On examination his foot is insensate and a dorsalis pedis pulse is only weakly felt. Which of the biochemical abnormalities listed below is most likely to be present?
Alkalosis Hypercalcaemia Hypocalcaemia Hyperkalaemia Hyponatraemia
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
A 39 year old lady has recurrent attacks of biliary colic. What is the approximate volume of bile to enter the duodenum per 24 hours?
500 mL 50 mL 100 mL 2000 mL 150 mL
500 mL
Between 500 mL and 1.5 L of bile enters the small bowel daily.
At which of the following sites is the most water absorbed?
Right colon Left colon Stomach Jejunum Duodenum
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
Which of the following is not a characteristic of the proximal convoluted tubule in the kidney?
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) Glucose is reabsorbed by a process of facilitated diffusion
Its secretory function is most effective at low systolic blood pressures (typically less than 100mmHg)
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.
An arterial blood gas sample is taken and the following results obtained;
PaO2 8kPa
PaCO2 4kPa
pH 7.4
With which of the following are these values most consistent?
Compensated metabolic alkalosis Pulmonary atelectasis Alveolar hypoventilation Residing at 4500M for 48 hours LAD occlusion
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.
Which of the following does not cause a normal anion gap acidosis?
Pancreatic fistula Acetazolamide Uraemia Ureteric diversion Renal tubular acidosis
Uraemia
Uraemia will typically cause a high anion gap acidosis. It is one of the unmeasured anions.
Which one of the following would cause a rise in the carbon monoxide transfer factor (TLCO)?
Emphysema Pulmonary embolism Pulmonary haemorrhage Pneumonia Pulmonary fibrosis
Pulmonary haemorrhage
Where alveolar haemorrhage occurs the TLCO tends to increase due to the enhanced uptake of carbon monoxide by intra-alveolar haemoglobin.
Which of the following is least likely to be associated with hypercalcaemia?
Thiazides Antacids Coeliac disease Sarcoidosis Zolinger-Ellison syndrome
Coeliac disease
Patients with coeliac disease tend to develop hypocalcaemia due to malabsorption of calcium by the bowel.
Release of somatostatin from the pancreas will result in which of the following?
Decrease in pancreatic exocrine secretions Contraction of the gallbladder Increase in the rate of gastric emptying Increased synthesis of growth hormone Increased insulin release
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.
A 34 year old lady develops septic shock and features of the systemic inflammatory response syndrome as a complication of cholangitis. Which of the following is not a typical feature of this condition?
Body temperature less than 36oC or greater than 38oC Respiratory rate >20 Lactate <4 mmol/L High levels of tumour necrosis factor α WCC >12,000 mm3
Lactate <4 mmol/L
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
Which of the following stimulates gastric acid secretion?
Cholecystokinin Gastric inhibitory peptide Secretin Histamine Somatostatin
Histamine
Which of the following statements relating to gastric acid secretions are untrue?
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 Histamine acts in a paracrine manner on H2 receptors H2 receptor antagonists will not completely abolish gastric acid production
The intestinal phase accounts for 60% of gastric acid produced
The intestinal phase of gastric acid secretion accounts for only 10% of gastric acid produced.
A 22 year old man is undergoing a daycase excision of a sebaceous cyst. He is needle phobic and as the surgeon approaches with the needle the patient begins to hyperventilate. He soon develops circumoral parasthesia and muscular twitching. Which of the following is the most likely explanation for this event?
Temporal lobe epilepsy Reduction in ionised calcium levels Increase in ionised calcium levels Fall in serum PTH levels Rise in serum PTH levels
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.
Which of the following inhibits gastric acid secretion?
Histamine Nausea Calcium Parasympathetic vagal stimulation Gastrin
Nausea
Nausea inhibits gastric secretion via higher cerebral activity and sympathetic innervation.
A 73 year old lady is diagnosed with hyperaldosteronism. From which of the following structures is aldosterone released?
Zona fasciculata of the adrenal gland Juxtaglomerular apparatus of the kidney Zona reticularis of the adrenal gland Adrenal medulla Zona glomerulosa of the adrenal cortex
Zona glomerulosa of the adrenal cortex
Aldosterone serves to conserve sodium and water. It is produced in the zona glomerulosa of the adrenal cortex.
Which of the following hormonal agents will increase secretions of water and electrolytes in pancreatic juice?
Secretin Aldosterone Somatostatin Cholecystokinin Adrenaline
Secretin
Secretin causes secretion of water and electrolytes
Cholecystokinin causes enzyme secretion
A 43 year old lady is admitted with cholestasis secondary to a stone impacted at the level of the ampulla of vater. Which of the following tests is most likely to be predictive of bleeding diathesis at the time of ERCP in this particular case?
Bleeding time Prothrombin time APTT Platelet count Factor I levels
Prothrombin time
Jaundice will impair the production of vitamin K dependent clotting factors. This is most accurately tested by measuring the prothrombin time.
Which of the following mechanisms best accounts for the release of adrenaline?
Release from the adrenal medulla in response to increased angiotensin 1 levels Release from the zona fasiculata from the adrenal gland in response to increased sympathetic discharge Release from the adrenal medulla in response to increased noradrenaline levels Release from the adrenal medulla in response to sympathetic stimulation from the splanchnic nerves None of the above
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.
The acute phase response to injury does not typically include:
Pyrexia Decreased albumin Hepatic sequestration of cations Increased transferrin Increased serum amyloid A
Increased transferrin
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
A 73 year old man presents to pre operative clinic for an elective total hip replacement. He is on furosemide for hypertension. His investigations reveal to the following results: Na 120 Urine Na 10 (low) Serum osmolality 280 (normal) What is the most likely cause?
Hypotonic hypovolaemic hyponatraemia Hypertonic hypovolaemic hyponatraemia Syndrome of inappropriate ADH secretion Over administration of 5% dextrose Glomerulonephritis
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.
