Question
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Answer
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Extracellular K+ ion concentration is (mM)
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4
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Typical intracellular Na+ ion concentration is (mM)
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15
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Extracellular HCO3- concentration is
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25mM
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Extracellular Cl-
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110mM
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Intracellular ionised Ca2+ concentration is
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0.1uM
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An example of a primary active ion-transporter is
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SERCA
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An example of a secondary active ion transporter is
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Na+-glucose symporter
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The Na+/K+ ATPase is directly inhibited by the drug
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cardiac glycoside
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Na+/K+ ATPase inhibition causes the following two effects
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fall of intracellular K+; rise of intracellular Na+
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The typical equilibrium potential for K+ ions (EK) across the plasmalemma of a resting nerve cell (measured inside relative to outside; in mV) is
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-90
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The typical equilibrium potential for Na+ ions (ENa) across the plasmalemma of a resting nerve cell (measured inside relative to outside; in mV) is
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60
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Raising the extracellular K+ concentration bathing a nerve cell would
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make EK less
negative (more positive)
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Reducing the extracellular concentration of Na+ ions would
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make ENa more negative
(less positive)
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In a nerve cell membrane, transmembrane K+ current during repolarisation of the action potential is 2 nanoAmperes. Assuming each individual K+ channel carries a net current of 1 picoAmpere, and has a statistical probability of opening of 0.5, calculate the number of functional K+ channels.
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4000
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What is the approximate conduction velocity of an unmyelinated nerve of at least 5µm diameter?
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5m/s
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What is the approximate conduction velocity of a myelinated nerve of at least 5µm diameter?
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50m/s
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What is the typical duration of a nerve action potential at 37°C?
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2ms
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The velocity of propagation of an action potential in nerve fibres is increased by
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a decreased membrane conductance
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A rapidly acting, reversible inhibitor of nerve conduction is
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tetrodotoxin
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The principal autonomic neurotransmitter released at sympathetic ganglia is
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acetylcholine
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The principal post-synaptic receptor sub-type in parasympathetic ganglia is
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nicotinic
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Chemical transmission at the skeletal neuromuscular junction is blocked by
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tubocurarine
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Acetylcholine applied to the heart
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decreases atrial contractility
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Noradrenaline released at a noradrenergic synapse is removed from the cleft by
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both presynaptic and postsynaptic reuptake
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A person with a steady cardiac output consumed 400mL of oxygen every minute. An arterial blood sample contained 190 mL of O2 per litre of blood, while a sample from the pulmonary artery contained 140 mL of O2 per litre of blood. What was the person's cardiac output?
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8L/min
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Is a cardiac output of 8L/min higher, lower or the same as the typical value for an adult 70 kg man at rest?
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higher
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Stimulation of the sympathetic outflow to the cardiovascular system would initially
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have a positive chronotropic effect on the heart
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Administration of an α1 adrenoceptor antagonist (eg. Prazosin) would
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decrease arterial
blood pressure
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An increase in Vagal activity
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activates muscarinic receptors in the sino-atrial node
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Cardiac glycosides may act to increase the force of contraction of cardiac muscle by opening voltage gated Na+ channels
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false
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Cardiac glycosides may act to increase the force of contraction of cardiac muscle by increasing cytoplasmic free Ca2+ concentration
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true
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Cardiac glycosides may act to increase the force of contraction of cardiac muscle by reducing Ca2+ extrusion on sarcolemmal Na+-Ca2+ exchange
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true
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Cardiac glycosides may act to increase the force of contraction of cardiac muscle by inhibiting Na+/K+ ATPase activity - True
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true
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Cardiac glycosides may act to increase the force of contraction of cardiac muscle by inhibiting sarcoplasmic reticular Ca2+ pump activity
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false
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Arterial PO2 is normally
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100mmHg
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A fall of arterial PO2 can stimulate
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chemoreceptors in the carotid body
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A fall of pulmonary arterial and alveolar PO2
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constricts pulmonary arterioles
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PaCO2 in a healthy resting individual is typically (mm Hg)
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40
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A rise of arterial PCO2 can initially reduce arterial pH by
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reacting with arterial water
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inulin appearing in the urine 450 mg/min
renal plasma flow 500 ml/min
hydrostatic pressure within the glomerulus 45 mmHg
hydrostatic pressure within the Bowman's capsule 4 mmHg
plasma inulin concentration 3.0 mg/ml Determine the glomerular filtration rate (ml/min) using any of the following values you require
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150ml/min
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Individual nephrons can control their own glomerular filtration rate (autoregulation) through a process called tubulo-glomerular feedback. The cells that sense the composition of the tubular feedback are
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macula densa cells
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Identify a mechanism or drug that would increase glomerular filtration
rate
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efferent arteriole vasoconstriction
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Hypoproteinemia will cause glomerular filtration rate to
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increase
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This change (hypoproteinemia) in glomerular filtration rate is because of
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the fall in plasma oncotic pressure
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The U-shaped arrangement of the vasa recta blood vessels in the medulla of the kidneys
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minimises disruption of the osmotic gradient that exists within the medullary
interstitium
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Renin secretion by juxta-glomerular cells in the kidney
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increases Na+ reabsorption by the kidney
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Anti-diuretic hormone is secreted by
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the posterior pituitary gland
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Na+-HCO3- co-transporters are expressed
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in the basolateral membrane of proximal tubular epithelium
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NaHCO3 reabsorption by the kidney
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raises plasma pH
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In a practical class, a healthy student drank a litre of water in five minutes. Over the next thirty minutes the student produced 150 ml of urine, with a urea concentration of 96 mmol/litre. A blood sample gave a plasma urea concentration of 6 mmol/litre. Calculate the urine flow rate (in ml/min)
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5
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In a practical class, a healthy student drank a litre of water in five minutes. Over the next thirty minutes the student produced 150 ml of urine, with a urea concentration of 96 mmol/litre. A blood sample gave a plasma urea concentration of 6 mmol/litre. Calculate urea clearance (in ml/min)
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80
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Is a urea clearance 80ml/min larger, the same or smaller than the glomerular filtration rate?
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smaller
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Name an example of an accurate marker of glomerular filtration rate.
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inulin
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Accurate markers for glomerular filtration rate must be ... by the glomerulus.
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passively filtered
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A main function of the colon is the net absorption of
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water, Na+ and Cl-
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Glucose absorption from the lumen of the intestine is via
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apical sodium-dependent
glucose transporter (SGLT); basolateral glucose transporter (GLUT)
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Protein digestion is catalysed by proteases secreted from
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exocrine pancreas
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Salivary secretion contains
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K+
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The major anion secreted by pancreatic duct cells is
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HCO3-
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Bile is used for
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emulsifying fats
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Bile from the liver can be stored in the
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gall bladder
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Bile stored in the gall bladder can be released by the hormone
|
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Cholecystokinin is released from the
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duodenum
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Cholecystokinin is released in response to
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chyme
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Acetazolamide
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Carbonic anhydrase
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Omeprazole
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Gastric H+/K+ ATPase
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Spironolactone
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Aldosterone receptor
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Dobutamine
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Beta1 adrenoceptor
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Suxamethonium
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Neuromuscular junctional nicotonic receptor
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Which of the following drugs is a Ca2+ channel antagonist that may be used for treatment of cardiac arrhythmias?
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verapapmil
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Verapamil has the effect of slowing conduction through the atrioventricular node
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slowing conduction through the atrioventricular node
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Drugs which block open or inactivated voltage-gated Na+ channels can
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reduce the rate of rise of the ventricular action potential
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A typical example of such a drug is
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lidocaine
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A drug that shows 'use-dependent block' of ion-channels is
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lidocaine
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10 mg of a dye (neglect its volume) was injected into the vein of a healthy adult. After equilibration a blood sample was taken and the dye concentration was found to be 3.33 µg/ml. Calculate plasma volume (rounded to the nearest litre)
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3
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State one assumption you need to make about the dye in order to calculate plasma volume
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is not excreted
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If the dye also passively equilibrated at equal concentration across cell walls, and within the interstitial fluid, what would its plasma concentration most closely match from the drop-down list (µg/ml)?
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0.24
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What would its concentration most closely resemble if it equilibrated equally throughout all compartments in the body (µg/ml)?
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0.24
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Assuming the haematocrit is 45%, what would be the blood volume in litres (rounded to the nearest litre) that corresponds to typical plasma volume?
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5
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Give three important factors which govern fluid exchange across the endothelial wall of muscle capillaries and the surrounding interstitial space.
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capillary filtration coefficient; net hydrostatic force; net oncotic force
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The net hydrostatic force (Pcap) is most subject to short-term physiological control.
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true
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Some 20% of the interstitial fluid formed returns to the circulation via the lymphatic system.
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true
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