Question
|
Answer
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What is the typical concentration of plasma glucose (fasting)?
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4mM
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What is the typical concentration of plasma bicarbonate?
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25mM
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Normal plasma osmolarity is
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290mOsm
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Normal blood pH (arterial) is
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7.4
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If the extracellular potassium concentration is doubled, what happens to the resting nerve cell
membrane potential?
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depolarised
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Action potential conduction velocity in the largest myelinated nerve fibre is
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120m/s
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Myelination increases conduction velocity because it
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permits saltatory conduction
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Select one drug that can block voltage-gated Na+ channels
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lidocaine
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The sequence of nerve block by local anaesthetics is
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pain first, then general sensory, then motor last
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A clinical use of a voltage-gated K+ channel blocker is
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antidysrhythmic
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A competitive antagonist at the muscarinic neuroeffector junction
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atropine
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A depolarising blocker at the skeletal neuromuscular junction
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suxamethonium
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A blocker of autonomic ganglia receptors
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hexamethonium
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A blocker of noradrenaline uptake into nerve terminals
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cocaine
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A competitive antagonist of beta1-adrenoceptors
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propranolol
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The presence of haemoglobin in normal arterial blood increases its oxygen concentration by how many times?
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70
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An increase in ... increases the oxygen affinity of haemoglobin
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carbon monoxide added to blood
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Most of the carbon dioxide transported in the blood is in the form of
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bicarbonate
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Pulmonary surfactant is produced by
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type II alveolar cells
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Give a metabolic function that the lung does not perform
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generating erythropoietin
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Sympathetic nerves innervate the motor endplate in skeletal muscle
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false
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Parasympathetic nerves innervate the motor endplate in smooth muscle
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false
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Smooth muscle of the gastrointestinal tract is directly innervated mainly by sympathetic nerves
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false
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Endothelial cells lining blood vessels can generate nitric oxide
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true
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Parasympathetic nerves contract bladder smooth muscle
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true
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What does the P wave represent?
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atrial depolarisation
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What does the T wave represent?
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ventricular repolarisation
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Suppose a patient ingests a drug that partially blocks the delayed rectifier-type K+ channel in the heart. What would happen, if anything, to the Q-T interval?
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increase
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Look at the next ECG (Trace B). How does it differ from the normal ECG in Trace A?
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Less
frequent QRS complex
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What might be the cause of the altered activity in Trace B?
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atrio-ventricular block
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Systemic arterial blood pressure (mm Hg)
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120/80
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Pulmonary arterial blood pressure (mm Hg)
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20/10
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Resting cardiac output
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5L/min
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Basal oxygen consumption
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250ml/min
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Ventilation (at rest)
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6L/min
|
atropine
|
muscarinic acetylcholine receptor
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serotonin
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5-hydroxytryptamine receptors
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morphine
|
mu-receptor agonist
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insulin
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tyrosine kinase receptors
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steroids
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receptors that modify DNA transcription
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Emptying of the gut is stimulated by
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parasympathetic nerves
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Give TWO agents likely to cause constipation
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hexamethonium; morphine
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Loss of sympathetic nerve activity will produce
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diarrhoea
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Blockade of cholinesterase will produce
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diarrhoea
|
Clearance is defined as the
|
rate of elimination of drug / plasma concentration
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In general, for a given clearance the rate of elimination of a drug will vary
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directly with the plasma drug concentration
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If the elimination rate is expressed in mg/min and plasma concentration in mg/ml, the units of clearance are
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ml/min
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The clearance of gentamicin in a 60 kg woman is 5 L/hour. Calculate the dose to be given by intravenous injection every 8 hours to achieve a mean steady-state concentration (Css) of 4 mg/L.
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160mg
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Because of deteriorating renal function the half-life in this patient increases from 2 hours to 12 hours but the original dose is maintained. What new mean steady-state concentration will be reached under these changed circumstances?
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24mg/L
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Histamine is secreted by
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parietal cells
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Give 2 actions which result in histamine secretion
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parasympathetic
stimulation; stretch
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Histamine stimulates the secretion of
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gastric acid
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This secretion is by action at
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H2 receptors
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NA is released from preganglionic sympathetic nerves.
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false
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NA is synthesised outside the vesicle in nerve terminals and then transported into the vesicle.
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false
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Released NA acts on muscarinic M3 receptors in bladder smooth muscle.
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false
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Once released the action of NA is terminated by tyrosine hydroxylase.
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false
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NA, by action at beta1-adrenoceptors, increases cAMP levels in the heart.
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true
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One endocrine function of the kidney is
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vitamin D activation
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The normal glomerular filtration rate (GFR) is
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180L/day
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One factor favouring filtration is the glomerular hydrostatic pressure which is
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60 mmHg
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One factor opposing filtration is the glomerular capillary colloid osmotic pressure which is
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32mmHg
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Strong activation of renal sympathetic nerves
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decreases GFR
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The extracellular plasma volume is
|
3L
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The interstitial fluid volume is
|
10L
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The intracellular fluid volume is
|
28L
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The total transcellular fluid volume is
|
1L
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The total body fluid volume is
|
42L
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Nicotinic receptors are found in
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parasympathetic ganglia
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Muscarinic receptors are found in
|
endothelial cells
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Bradycardia is produced by acetylcholine action on
|
M2 muscarinic cardiac receptor
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The TWO main mechanisms underlying bradycardia are
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a decrease in cAMP; potassium channel activation
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Normal volume of anatomic dead space
|
150ml
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The PO2 in a red blood entering a pulmonary capillary
|
40mmHg
|
The mean pressure in the main pulmonary artery is
|
15mmHg
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Tissue PO2 can be as low as
|
1mmHg
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For dissolved oxygen, Henry's law states that the amount dissolved is
|
proportional to concentration
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The upstroke of the action potential in cardiac pacemaker cells is due to
|
L-type voltage gated Ca2+ channels
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The action potential in ventricular myocytes normally has an approximate duration of
|
300ms
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Hyperpolarisation is due to
|
voltage-gated K+ channel
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When exercising vigorously the maximum heart rate (beats per min; bpm) can reach
|
180bpm
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Regarding the rate of rise of the cardiac action potential, local anaesthetics will
|
decrease it
|
cortisol
|
adrenal cortex
|
growth hormone
|
anterior pituitary
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glucagon
|
pancreas
|
calcitonin
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thyroid
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estrogen
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ovaries
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Insulin is a
|
protein
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Insulin is produced by the ... cells of the pancrease
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beta
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Insulin secretion is stimulated by
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amino acids
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Glucagon is a
|
polypeptide
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Glucagon is synthesised in ... cells
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alpha
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The upstroke of the action potential in skeletal muscle is usually blocked by calcium channel blockers.
|
false
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Skeletal muscle fibres have a well-defined t-tubule system.
|
true
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Sarcomeres are poorly developed in skeletal muscle.
|
false
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Troponin C binds calcium and initiates cross bridge cycling.
|
true
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The endplate potential is initiated by the actions of acetylcholine released from somatic motor nerves acting at muscarinic M3 receptors.
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false
|