ELFH - Physiology Flashcards

Question 1

Q

TRUE/FALSE

Cardiac output increases with:

A. Heart rate
B. Increased systemic vascular resistance
C. A decrease in dp/dt
D. Hyperkalaemia
E. An increase in LVEDV

Answer

A

True. CO = HR X SV. An increase in heart rate will increase cardiac output until the point where filling time is compromised.

False. Increased SVR results in increased afterload and a reduced cardiac output.

False. dp/dt represents contractility.

False. Hyperkalaemia has a negative ionotropic effect.

True. LVEDV represents preload.

Question 2

Q

TRUE/FALSE

Concerning the cardiac cycle:

A. Aortic blood flow is lowest at the end of diastole
B. Aortic pressure is highest in mid systole
C. Atrial contraction can account for 40% of ventricular filling
D. The QRS complex on the ECG occurs immediately before the rapid ejection phase
E. The aortic valve opens at the start of ventricular systole

Answer

A

False. It is lowest in early diastole.

True.

True. At rest it is normally closer to 20%, but increases to as much as 40% with tachycardia.

False. The QRS complex occurs immediately before isovolumetric contraction.

False. The initial phase of ventricular contraction is isovolumetiric, with the aortic valve closed. Once LV pressure exceeds aortic pressure, the aortic valve opens.

Question 3

Q

TRUE/FALSE

Responses to acute haemorrhage may include:

A. Reduced ADH secretion
B. Increased sympathetic output
C. Reduced baroreceptor discharge
D. Increased glucagon release
E. Increased interstitial fluid formation

Answer

A

False. AdH secretion increases

True. Initially, sympathetic nerve activity is increased. When blood volume is critically depleted, peripheral sympathetic drive falls steeply.

True. The baroreceptors increase efferent output in response to stretch.

True.

False. Fluid enters the capillaries from the interstitium as a result of reduced hydrostaic capillary pressure.

Question 4

Q

TRUE/FALSE

In the fetal circulation at birth:

A. The pulmonary vascular resistance halves
B. Systemic vascular resistance rises
C. Left atrial pressure rises
D. The ductus arteriosus should close within 48 hours
E. The foramen ovale fuses

Answer

A

False. With the first gasp, PVR falls by > 80%.

True. Largely due to intense vasoconstriction of the umbilical vessels.

True. Due to increase pulmonary blood flow.

True. A High PaO2 appears to initiate closure. Prostaglandins maintain its patency.

False. It closes as left atrial pressure rises, but does not fuse for around 48 hours.

Question 5

Q

TRUE/FALSE

The following increase the movement of fluid out of capillaries:

A. Venous hypertension
B. Decrease in oncotic pressure
C. Arteriolar vasoconstriction
D. Hypotension
E. Decrease in hydrostatic pressure in capillaries

Answer

A

True.

False.

Factors which increase flow out of capillaries are increased capillary hydrostatic pressure, increased interstitial colloid osmotic pressure, reduced interstitial hydrostatic pressure or reduced colloid oncotic pressure. In certain conditions (eg sepsis) the permeability coefficient may be altered.

Question 6

Q

TRUE/FALSE

The a-wave in the jugular venous pulse:

A. Is caused by atrial filling during ventricular systole
B. Is elevated in tricuspid stenosis
C. Is elevated in atrial fibrillation
D. Is elevated in tricupid regurgitation
E. When enlarged are known as canon waves

Answer

A

False. This would be the v-wave. The a-wave is due to atrial contraction.

True.

False. It is absent in atrial fibrillation due to the lack of atrial contraction.

False. The v-wave is elevated in tricupid regurgitation.

True. Canon waves are large waves corresponding to atrial contraction against a closed tricuspid valve. They are seen in complete heart block or junctional arrhythmias.

Question 7

Q

TRUE/FALSE

In cardiac ventricular muscle:

A. Cells exhibit automaticity
B. The cells membranes are largely impermeable to negatively charged ions
C. Depolarization is followed by a plateau potential lasting about 200 ms
D. Rapid depolarzsation is mainly due to calcium influx throught transient (T-type) calcium channels.
E. Cannot be tetanized

Answer

A

False. This behaviour is exhibited primarily by pacemaker cells allowing spontaneous depolarisation. However if this apparatus is disrupted an escape rhythm may originate from in/below the AV node in a junctional escape rhythm, or in the Purkinje fibres in a ventricular escape rhythm.

True. These include proteins, sulphates and phosphates which thus remain intracellularly and contribute to the negative RMP.

True. Due to Calcium influx via slow L-type calcium channels.

False. Rapid depolarization of myocardial cells is due to sodium influx. Depolarisation of slow-response action potentials of pacemaker cells is due to calcium influx throught transient (T-type) calcium channels.

True. The prolonged refractory period prevents tetany.

Question 8

Q

TRUE/FALSE

Concerning coronary blood flow:

A. It is increased during hypoxia
B. It is approximately 25% of the cardiac output at rest
C. Significant right coronary artery perfusion occurs during systole
D. The coronary cirulation has the highest A-V oxygen difference of all the major organs
E. Coronary blood flow is regulated via the baroreceptor reflexes

Answer

A

True. Hypoxia increases coronary blood flow 2-3 fold.

False. Normal coronary blood flow at rest is approximately 250 ml/min or 5% of the cardiac output.

True. Unlike the left ventricle, the right ventricle receives most perfusion during systole due to its lower wall pressures.

True. The myocardium extracts 70% of oxygen.

True. Aortic pressure provides the main driving force for coronary blood flow and this pressure is controlled by baroreceptor reflexes. Flow is also affected by many local factors, including systolic compression and local metabolic factors.

Question 9

Q

TRUE/FALSE

Cardiac excitation in the normal heart:

A. Is initiated spontaneously in the sino-atrial (SA) node
B. Transmission through the atrium takes 0.4 s
C. The AV node allows rapid transmission of electrical excitation to the ventricle
D. The preferential route of transmission from right to left atrium is via Bachmann’s bundle
E. Gap junctions allow the myocardium to act as a single contractile unit

Answer

A

True.

False. Transmission through the atrium and the AV node to the venticular myocardium takes 0.2 s.

False. Transmission is slowest at the AV node.

True. Also known as the anterior interatrial band.

True. Gap junctions are located at the intercalated disc and allow electrical impulses to propagate freely.

Question 10

Q

TRUE/FALSE

The Valsalva Manoeuvre:

A. At the onset of the Valslava manouvre arterial pressure rises
B. The reduced arterial pressure seen during the Valslva manouvre will be exagerated in hypovolaemia
C. Heart rate changes are mediated via the aortic chemoreceptors
D. The bradycardia seen after the termination of the manouvre is absent in most long-standing diabetics
E. Increases the intensity of the heart mumur associated with aortic stenosis

Answer

A

True. Due to the the effect of increased intrathoracic pressure on the aorta.

True. After the initial rise, BP then falls due to the effect of raised intrathoracic pressure on venous return - this will be more pronounced in the hypovolaemic and can result in cardiovascular collapse.

False. Pressure changes are detected by baroreceptors.

False. Autonomic neuropathy results in an absence of heart rate changes, but this is seen in only 20-40% of long-standing diabetics.

False. It increases the murmur of mitral regurgitation, but most other mumurs are decreased.

Question 11

Q

TRUE/FALSE

At birth:

A. The foramen ovale closes because of a reversal of the pressure gradient between the left and right atria
B. The ductus arteriosus closes because of a respiratory acidosis
C. Blood flow in the IVC falls
D. Hypoxia will favour a right to left shunt
E. The first breath generates a negative pressure of about 50 cmH2O

Answer

A

True.

False. The ductus arteriosus closes functionally soon after birth (usually within 24 hours) due to exposure to oxygenated blood and reduced prostaglandin-E2.

True.

True. Any stimulus increasing Pulmonary Vascular Resistance will favour a right to left shunt and hence a Persisitent Fetal Circulation. These stimuli include hypoxia, hypercarbia, acidosis and hypothermia.

True.

At birth, pulmonary vascular resistance falls markedly as the lungs expand and fill with air. This decreases pulmonary artery pressures and increases blood flow to the left atrium. Umbilical vessels constrict and placental circulation ceases resulting in increased systemic vascular resistance and arterial pressure. Left atrial pressure becomes higher than right atrial pressure and this closes the foramen ovale.

Question 12

Q

TRUE/FALSE

Left ventricular end diastolic pressure (LVEDP):

A. Gives an index of preload
B. Will be raised if left ventricular compliance increases
C. Is increased in aortic regurgitation
D. Is a determinent of myocardial oxygen consumption
E. Is measured using a pulmonary artery flotation catheter

Answer

A

True. The best measure of preload in LVEDV, however this will correlate with LVEDP - the exact numerical relationship being dependent on left ventricular compliance.

False. Pressure will be lower for a given volume if compliance is increased (Complaince = Vol/Pressure)

True. Because regurgitant blood re-enters the ventricle increasing volume and pressure.

True. Raised LVEDP increases myocardial work and therefore oxygen requirement.

False. A pulmonary artery flotation catheter can measure the left atrial pressure (wedge pressure).

Question 13

Q

TRUE/FALSE

An increase in right atrial pressure:

A. Decreases systemic arterial pressure
B. Will increase type A atrial stretch receptor discharge during atrial systole
C. Causes an increase in urine volume
D. Can increase the heart rate via the Bainbridge reflex
E. Can decrease the heart rate via the baroreceptor reflex

Answer

A

False. An increase in preload will increase LVEDV and therefore stroke volume and consequently cardiac output and arterial blood pressure (unless in heart failure).

True. Atria have Type A stretch receptors that discharge predominantly during atrial systole and Type B receptors that discharge predominantly during atrial diastole.

True. Stimulation of atrial stretch receptors causes the release of atrial naturetic peptide (ANP) which has a diuretic action.

True.

True. Increasing RA filling produces 2 opposing reflexes that control HR. The resultant increased blood pressure can decrease HR via the baroreceptor reflex, however the atrial stretch receptors can increase HR via the Bainbridge reflex. Whether the HR increases of decreases after a sudden increase in intravascular volume is thought to be related to the initial heart rate (decreasing if it is high and increasing if it is low).

Question 14

Q

TRUE/FALSE

In diastole:

A. Myocardial relaxation is metabolically active
B. Hypercalcaemia causes positive lusitropy
C. Left atrial contraction occurs just before right atrial contraction
D. The greater part of left coronary artery blood flow occurs during diastole.
E. Diastasis shortens first with increasing heart rate

Answer

A

True. Myocardial relaxation is a metabolically active phase when calcium re-uptake occurs by the sarcoplasmic reticulum.

False. Lusitropy is a term that decribes myocardial relaxation. Catecholamines have a positive lusitropic action (allowing rapid relaxation) whilst hypercalcaemia inhibits relaxation due to incomplete calcium reuptake (an essential process in diastole).

False. RA contration preceeds LA contraction, however LV contaction precedes RV contraction.

True. Whereas in the Right Coronary Artery, the greater part of blood flow occurs during systole.

True. Diastasis is the slow ventricular filling phase of diastole. There is only a small increase in ventricular volume during this time.

Question 15

Q

TRUE/FALSE

In the first 24 hours after major trauma:

A. Sodium is retained
B. Glomerular filtration rate increases
C. Patients will be immunosuppressed
D. Urinary nitrogen levels will rise
E. Insulin secretion is decreased

Answer

A

True. Aldosterone levels increase, promoting sodium reabsorption.

False. GFR decreases.

False. Immunusuppression is a late feature following trauma.

True. Due to protein breakdown in the initial catabolic phase.

True. Glucagon secretion also increases briefly.

Question 16

Q

TRUE/FALSE

Afterload:

A. Equals systemic vascular resistance
B. If increased, will result in decreased LVEDV
C. Is likely to be low in heart failure
D. Will be low in a dilated ventricle
E. Is decreased in mitral regurgitation

Answer

A

False. Afterload is the tension developed in the LV wall during systole. SVR is however the commonest index of afterload used clinincally, but it is only one component that determines afterload.

False. If afterload increases, SV initially falls. SV is then (partially) restored by an increase in LVEDV. This is known as the Anrep effect.

True. Afterload is the tension developed in the LV wall during systole and as such can be related to pressure by Laplaces law. Thus in the failing heart afterload is likely to be low due to low intraventricular pressure.

False. Using Laplaces law, the inreased radius will increase tension.

True. The left ventricle requires less tension to eject blood through this low pressure pathway.

Question 17

Q

TRUE/FALSE

Concerning the splanchnic circulation

A. The adult liver normally receives approximately one third of its blood supply from the coeliac axis
B. Beta 1 adrenergic receptors cause mesenteric arteriolar vasodilatation
C. Positive end expiratory pressure (PEEP) decreases portal blood flow
D. Arcades of arterioles supplying mucosal villi terminate and branch at the tip supplying well oxygenated blood to the mucosa
E. The splanchnic venous system can contain 1/3 of the total blood volume

Answer

A

True. The hepatic artery is a branch of the coeliac axis. There is an inverse ratio of the flow between the hepatic artery and portal vein but under normal conditions 1/3 of hepatic blood comes from the hepatic artery.

False. Beta 2 adrenergic receptors mediate vasodilation.

True. Portal blood flow does not autoregulate well. PEEP increases hepatic venous pressure and reduces portal flow.

False. The countercurrent exchange of oxygen between parallel arterioles and submucosal venules makes oxygen delivery to the tips of mucosal villi poor.

True. The splanchnic and skin circulations are the major reservoirs of available blood in times of stress.

Question 18

Q

TRUE/FALSE

Concerning cardiac tissue:

A. Myocardial cells have a RMP of -60mV
B. Myocardial cells do not possess gap junctions
C. Conduction velocity of action potentials is greatest in the bundle branches and Purkinje system
D. Calcium within the sarcoplasmic reticulum is released in response to rising intracellular sodium levels
E. Both the SA and AV nodes blood supply is derived from the right coronary artery

Answer

A

False. This is the RMP of pacemaker cells. Myocardial cells have a RMP of -90 mV.

False. Gap junctions connect the cytosol of adjacent myocardial cells allowing rapid transmission of electrical cells.

True.

False. It is released in response to rising intracellular calcium levels.

True.

Question 19

Q

TRUE/FALSE

During moderate exercise:

A. Cerebral blood flow increases
B. Increased cardiac output is achieved mainly from an increased heart rate
C. Central venous pressure rises
D. Intravascular volume is usually reduced
E. Haematocrit tends to fall

Answer

A

False. CarDiac output by upto seven times resting values, but cerebral blood flow is maintained at normal levels.

True.

False. At moderate levels of exercise, increased venous return matched increased cardiac output and thus CVP does not significantly change. CVP does rise at maximal exertion.

True. Due to increased insensible losses and increased capillary filtration.

False. There is often a slight rise in haematocrit due to the reasons in Part D.

Question 20

Q

TRUE/FALSE

Regarding electrolyte changes:

A. Hypokalaesmia increases automaticity
B. Hypokalaemia increases the QT interval
C. Hyperkalaemia brings the RMP closer to the threshold potential
D. Hypercalcaemia makes the threshold potential more negative
E. Hypermagnesemia prolongs the PR interval

Answer

A

True. Hypokalaemia makes the cardiac muscle RMP more negative, resulting in it being less excitable but with increased automaticity.

True.

True. Hyperkalaemia makes the RMP less negative.

False. Hypercalcaemia makes the threshold potential less negative, decreases conduction velocity and shortens the refractory period.

True. Hypermagnesemia delays AV conduction.

Question 21

Q

TRUE/FALSE

Breathing spontaneously in the lateral position:

A. Perfusion is greater in the dependent lung
B. Ventilation is decreased in the uppermost lung
C. V/Q is higher in the dependent lung
D. Dependent lung has a lower PO2
E. Non-dependent lung has a higher PCO2

Answer

A

True.

False. In the awake adult, ventilation and perfusion are greater in the lower (dependent) lung although perfusion is slightly better than ventilation and so V/Q < 1.

True. V/Q is < 1, ie there is a degree of shunt. In areas of shunt alveolar gas tends toward mixed venous so PAO2 is low and PACO2 slighlty raised.

False. In the non-dependent lung V/Q > 1, ie a degree of dead space. Alveolar gas now tends toward inspired gas and so PO2 is raised but PCO2 is low.

Question 22

Q

TRUE/FALSE

FRC can be measured using:

A. Body plethysmography
B. Nitrogen wash-out
C. Spirometry
D. Helium wash-in
E. Intra-oesophageal balloon

Answer

A

True.

False.

True.

False. Intra-oesophageal balloons are used to measure intra-pleural pressure.

Spirometry will measure all lung volumes except FRC, residual volume and TLC. This is because on the y-axis of the spirometry trace, it is not possible to say where zero lies (although it is often labelled as such in text books).

Question 23

Q

TRUE/FALSE

Concerning 2,3, DPG:

A. It binds the beta chains of deoxyhaemoglobin
B. It is formed from a product of glycolysis
C. An increased concentration increases oxygen utilisation by cells
D. Its red cell concentration is increased by circulating thyroid hormones
E. Is strongly bound by fetal haemoglobin

Answer

A

True.

True. 2,3-DPG is formed in red blood cells from phosphoglyceraldehyde, a product of glycolysis.

True. 2,3 DPG shifts the O2 dissociation curve to the right, reducing oxygen binding to haemoglobin and thus increasing oxygen availability for tissue utilization.

True. Thyroid hormones, along with growth hormone and angrogens increase 2,3,DPG concentration.

False. Fetal Hb does not contain beta chains.

Question 24

Q

TRUE/FALSE

Dipalmitoylphosphatidylcholine:

A. Is a mucopolypeptide
B. Causes an increase in surface tension
C. Causes an increase in chest wall compliance
D. Production is reduced in low cardiac output states
E. Maintains the same surface tension for different sized alveoli

Answer

A

False. It is a phospholipid, found in lung surfactant.

False. Surfactants role is to decrease surface tension.

False. It increases lung compliance, not chest wall compliance.

True. As it is derived from free fatty acids carried in the blood stream.

False. It is more effective at reducing surface tension in small alveoli. This reduces the effect of Laplace’s law, which would otherwise cause small alveoli to collape.

Question 25

Q

TRUE/FALSE

Peripheral chemoreceptors:

A. Are found in the carotid sinus
B. Are downregulated in the presence of chronic lung disease
C. Are stimulated by elevated levels of carboxyhaemoglobin
D. Give rise to increased afferent signals when PaO2 falls below 13 kPa
E. Maintain PaCO2 within the range 4.5-6.0 kPa

Answer

A

False. They are located in the carotid and aortic bodies.

False. Central chemoreceptors in the medulla respond to a rise in PaCO2 and CSF pH.

False.

True. The carotid body is the prime O2 sensory organ.

False. see part D.

Ventilation is predominantly controlled by central chemoreceptors in the medulla which respond to a rise in PaCO2 and CSF pH.

Question 26

Q

TRUE/FALSE

Carbon dioxide:

A. Freely diffuses across the blood : brain barrier
B. Is lagely transported unchanged
C. Gives rise to the same pH change in CSF as it does in blood
D. Transport by haemoglobin is inhibited by rising oxygen saturation
E. Has direct sympathomimetic activity

Answer

A

True. Unlike H+ ions and HCO3-.

False. Most is transported as bicarbonate. Around 5% is transported unchanged in the blood.

False. pH changes are greater in the CSF due to the lack of buffers.

True. By the Haldane effect.

False. But it does increase activation of the sympathetic system.

Question 27

Q

TRUE/FALSE

Pulmonary blood flow:

A. Is normally less than the cardiac output
B. Has a mean arterial pressure of 25-30 mmHg
C. In West zone 1, occurs mainly during diastole
D. Of 6000 ml/min with a minute ventilation of 4000 ml/min suggests the presence of a shunt
E. Is maximal in zone 2

Answer

A

True. A small proportion of the cardiac output will be anatomical shunt.

False. Mean pressure is around 15 mmHg. 25 -30mmHg would be the systolic pressure.

False. In West zone 1 pA>pa>pv therefore the pulmonary capillary is completely compressed by by the alveolus ceasing. This results in a very high V/Q ratio

True. As perfusion is significantly greater than ventilation.

False. It is maximal in zone 3.

Question 28

Q

TRUE/FALSE

Restrictive lung disease is characterized by:

A. A fall in FEV1
B. A fall in arterial PO2
C. A fall in FEV1/FVC ratio
D. Carbon dioxide retention
E. A fall in vital capacity

Answer

A

True. Pulmonary function tests generally reveal a decrease in both FEV1 and FVC with a normal FEV1/FVC ratio.

True. A fall in FRC causes alveolar collapse with a resultant shunt.

False.

True. As does TLC and FRC.

Question 29

Q

TRUE/FALSE

During intermittent positive pressure ventilation:

A. Mean intrathoracic pressure will be lower than during spontaneous breathing
B. Right ventricular filling falls compared with spontaneous ventilation
C. PEEP will reinflate collapsed alveoli
D. Right ventricular workload may increase
E. Left ventricular workload may decrease

Answer

A

False.

True. Which will reduce cardiac output.

False. PEEP will prevent collapse, but would not normally be high enough to re-inflate collapsed lung.

True. PVR may rise during IPPV due to hyperinflation or alveolar collpase (PVR is lowest at FRC and rises above or below this).

True. IPPV reduces LV afterload by decreasing LV cavity size and transluminal wall tension.

Question 30

Q

TRUE/FALSE

Hyperventilation produces:

A. Muscle spasm
B. A raised pH
C. Decreased cerebral blood flow
D. Peripheral vasodilatation
E. Increased cardiac output

Answer

A

True. Alkalosis decreases the proportion of ionised calcium, causing tetany.

True.

False. Hypocarbia causes vasoconstriction by a direct effect.

False. Hypercarbia causes an increase in cardiac output due to increased sympathetic activity. The direct effect of vasoconstriction from hypocarbia will reduce cardiac output.

Question 31

Q

TRUE/FALSE

Concerning the enteric nervous system:

A. It contains pre-ganglionic cholinergic fibres
B. Vagal fibres are post-ganglionic
C. It contains post-ganglionic sympathetic fibres
D. Many sympathetic fibres end on cholinergic neurones
E. Many sympathetic fibres end directly on intestinal smooth muscle

Answer

A

True. Generally, the parasympathetic supply to the GIT is via pre-ganglionic vagal fibres.

False.

True. The sympathetic supply is post-ganglionic, but may end on cholinergic neurones or on smooth muscle fibres directly.

True.

Question 32

Q

TRUE/FALSE

Concerning nerve conduction:

A. A-delta fibres are the slowest as they are unmyelinated
B. A-beta fibres exhibit saltatory conduction
C. C fibres are myelinated
D. A-alpha fibres conduct at 30-70 m/s
E. A-delta fibres provide sensory innervation to muscle spindles.

Answer

A

False. A and B fibres are myelinated and therefore have fast conduction velocities due to saltatory conduction.

True.

False.

False. A-alpha fibres conduct at 70-120 m/s

False. But A-gamma fibres provide motor supply to muscle spindles.

Question 33

Q

TRUE/FALSE

Hemisection of the spinal cord causes:

A. Ipsilateral paralysis
B. Ipsilateral loss of proprioception
C. Contralateral loss of pain sensation
D. Ipsilateral loss of vibration sense
E. Contralateral loss of temperature sensation

Answer

A

True.
True.
True.
True.
True.

Brown-Sequard syndrome (hemisection of the spinal cord) causes ipsilateral paralysis and loss of proprioception, touch and vibration sensation, with contralateral loss of pain and temperature sensation.

Question 34

Q

TRUE/FALSE

Concerning synaptic transmission:

A. The synaptic cleft is 100 nm wide
B. Temporal summation may occur
C. Synaptic delay is normally 0.1 ms
D. IPSPs are depolarising
E. EPSPs are depolarising

Answer

A

False. The synaptic cleft is 30-50 nm wide.

True. Summation of excitatory postsynaptic potentials may be both spatial and temporal.

False. Synaptic delay is normally 0.5 ms.

False. IPSPs are hyperpolarising.

True.

Question 35

Q

TRUE/FALSE

Concerning the knee jerk reflex:

A. It is monosynaptic
B. The synaptic transmitter is glutamate
C. The sensory organ is the muscle spindle
D. It involves spinal roots L2,3,4
E. Glycine inhibition occurs in fibres to antagonistic muscles.

Answer

A

True.
True.
True.
True.
True. The sensory organ is the muscle spindle, which when stretched sends signals to the CNS where a single synapse occurs with the motor supply to the muscle. In addition the Ia fibre from the muscle spindle synapses with an inhibitory interneurone (golgi bottle neurone) which releases inhibitory glycine at the motor neurone to the antagonistic muscle - known as reciprocal innervation.

Question 36

Q

TRUE/FALSE

Concerning the visual pathway:

A. Optic tract lesions will cause a bitemporal hemianopia
B. Optic chiasm lesions will cause a bitemporal hemianopia
C. Occipital lesions may spare the macula
D. Optic nerve lesions will cause bilateral loss of vision
E. Field defects start as scotomas.

Answer

A

False. Optic tract lesions cause homonymous hemianopia since the optic tracts carry fibres that supply the same field (ie left or right) from both eyes.

True. As at the Optic chiasm, temporal fibres cross the midline.

True. As the macula fibres are separated from the rest of the cortex subserving vision.

False. They will cause unilateral loss of vision.

True. These are small areas of visual loss.

Question 37

Q

TRUE/FALSE

Concerning pain pathways:

A. A-delta have cell bodies within the vental root ganglion of the spinal cord
B. A-delta fibres synapse with cells of the substantia gelatinosa of the spinal cord
C. C fibres synapse with cells in laminae IV and V in the dorsal horn
D. Most ascending neurones are in the anterolateral columns
E. The substantia gelatinosa projects directly to higher levels

Answer

A

False. A-delta have cell bodies within the dorsal root ganglia.

False. A-delta fibres synapse with cells in laminae I and V of the dorsal horn.

False. C fibres synapse with cells in laminae II and III in the dorsal horn.

True. Most second order neurones cross within a few segments and ascend in the anterolateral columns (spinothalamic tract).

False. The SG does not project directly to higher levels but contains multiple interneurones involved in pain modification.

Question 38

Q

TRUE/FALSE

Concerning sensory receptors:

A. Meissners corpuscles are associated with nociception
B. Ruffini corpuscles are associated with proprioception
C. Pacinian corpuscles are associated with vibration
D. Ruffini corpuscles are associated with nociception
E. Pacinian corpuscles are associated with proprioception

Answer

A

False. Meissners corpuscles are associated with touch.

True.

True. Pacinian corpuscles are associated with proprioception and vibration.

False. Free nerve endings are associated with nociception

True. Pacinian corpuscles are associated with proprioception and vibration.

Question 39

Q

TRUE/FALSE

Concerning the cranial nerves:

A. VII provides taste sensation to the posterior third of the tongue
B. V provides motor fibres to the jaw and tongue
C. IV innervates the inferior oblique muscle
D. III performs most eye movements
E. XII provides motor innervation to palatoglossus

Answer

A

False. Taste sensation to the posterior third of the tongue is provided by the glossopharyngeal (IX), the rest being supplied by the chorda tympani accompanying the facial nerve (VII).

False. The trigeminal nerve (V) supplies the muscles of mastication and sensation to the forehead and face in the distribution ophthalmic, maxillary and mandibular branches. This includes sensation from the cornea.

False. IV innervates the superior oblique muscle.

True. With IV and VI supplying superior oblque (to look down and inward) and lateral rectus (abduction) respectively.

False. XII innervates all tongue muscles except palatoglossus, which is innervated by X.

Question 40

Q

TRUE/FALSE

In the EEG, delta waves occur:

A. With increased cortical activity
B. Normally during sleep
C. Prominently over the frontal area
D. Upon closing the eyes
E. Normally in children

Answer

A

False.

True.

False.

True.

Delta waves are abnormal 4Hz waves, though they can be normal in children and during sleep. Alpha waves are prominent on closing the eyes or with increased cortical activity whilst beta waves prominent over the frontal area.

Question 41

Q

TRUE/FALSE

Ingested lipids:

A. Are mainly triglycerides
B. Are composed of essential and non-essential fatty acids
C. Are broken down primarily in the terminal ileum
D. Are used as a source of ATP
E. Increase in the faeces with a decrease in bile secretion

Answer

A

True. Triglycerides make up to 90% of dietary lipids.

True. Alpha-linolenic acid and linoleic acid are examples of essential fatty acids. Humans do not possess the enzyme systems to synthesize them.

False. 10-30% are broken down in the stomach, the rest is broken down in the duodenum and upper jejunum. Bile salts are absorbed in the terminal ileum.

True. It is a relatively energy dense molecule, providing more than double that from glucose.

True. Bile salts are required solubilizing agents for fats and aid in their absorption.

Question 42

Q

TRUE/FALSE

Regarding Basal Metabolic Rate (BMR):

A. It is the lowest possible rate
B. BMR decreases with age
C. For every 1 degree centigrade rise in body temperature, the BMR increases by 8%
D. BMR is the energy output of an individual per unit time at rest, at room temperature
E. May be measured using an ergometer

Answer

A

False. It can be lower when asleep.

True. It is higher in children. There is also a gender difference with males having a higher BMR than females.

False. This is true for the cerebral metabolic rate not the body’s basal metabolic rate.

True. It must also be measured 12-14 hr after their last meal (a time when one is said to be thermoneutral).

False. It may be measured indirectly using a Wet Spirometer not an ergometer. An ergometer is used to measure energy expenditure whilst active.

Question 43

Q

TRUE/FALSE

Insulin:

A. Is antagonised by growth hormone
B. Facilitates protein anabolism
C. Promotes glycogen synthesis in the liver
D. Facilitates the deposition of fat
E. Inhibits the passage of potassium ions into cells

Answer

A

True. The 5 counter-regulatory hormones that antagonise insulin-induced hypoglycaemia are adrenaline, noradrenaline, glucagon, growth hormone and cortisol.

True. Insulin is the only major anabolic hormone. Hence it stimulates synthesis of proteins, fat and glycogen.

True.

False. Insulin facilitates the passage of potassium ions into cells and is often used as a treatment for hyperkalaemia.

Question 44

Q

TRUE/FALSE

Considering lactate metabolism:

A. One molecule of lactate is produced for every glucose molecule during anaerobic metabolism
B. Fitness training does not affect the rate of rise in plasma lactate
C. Glucose metabolism to lactate releases ATP at the same rate as oxidation within the mitochondria
D. After exercise lactate is largely reconverted into glucose
E. Lactate filtered in the kidney is actively reabsorbed

Answer

A

False. Each glucose is converted to 2 pyruvate and these are converted to 2 molecules of lactate.

False. At a certain level of exercise the plasma lactate level rises sharply. This is at between 50-80% of maximal O2 consumption. In an untrained person plasma lactate will rise at a lower level of exercise than in the trained.

False. Glucose metabolism to lactate releases ATP at least twice as rapidly as mitochondrial metabolism and can optimally provide energy for 1.5 minutes of maximal muscle activity.

True. After exercise 80% of lactate present is reconverted to glucose in the liver via the Cori cycle.

True. Filtered lactate is actively reabsorbed by the nephron to a transport maximum of 75 mg/min.

Question 45

Q

TRUE/FALSE

Hyperglycaemia may result from the administration of:

A. Adrenaline
B. Thyroid stimulating hormone
C. Beta blockers
D. Thiazide diuretics
E. Glucagon

Answer

A

True. Adrenaline increases glucagon secretion and stimulates gluconeogenesis.

True. Thyroid hormone stimultaes: increased glucose absorption from the gut, glycogenolysis and gluconeogenesis.

False. Patients on beta blockers are at risk of hypoglycaemia under general anaesthesia.

True. Thiazide diuretics commonly precipitate Type 2 diabetes.

True.

Question 46

Q

TRUE/FALSE

Glucagon release:

A. Stimulates gluconeogenesis
B. Inhibits adenylate cyclase in liver cells
C. Stimulates secretion of growth hormone
D. Is inhibited by cortisol
E. Is stimulated by theophylline

Answer

A

True. Glucagon is gluconeogenic, glycogenolytic, and lipolytic.

False. It acts via G-protein linked receptors.

True. Glucagon is formed in the pancreatic alpha-cells. Secretion is stimulated by beta-mediated sympathetic nerves to the pancreas, acetylcholine, amino acids, CCK and gastrin.

False. Secretion is stimulated by cortisol and infection, but inhibited by alpha stimulation, insulin, glucose, ketones, phenytoin and somatostatin.

True. Theophylline and other phosphodiesterase inhibitors also stimulate its release.

Question 47

Q

TRUE/FALSE

In starvation:

A. Free fatty acid oxidation in the liver, muscle and heart is increased
B. Muscle glycogen and brain glycogen are replenished by gluconeogenesis
C. Ketone bodies produced in the liver from free fatty acids can be utilized by brain cells but glucose is still essential
D. Glucose can be formed from fatty acids
E. The odour of the breath is due to ketosis

Answer

A

True. In starvation, glycogenolysis occurs and the liver begins to use fatty acids as a source of energy.

False. As the glycogen is depleted, gluconeogenesis increases using amino acids from the breakdown of muscle protein. Glycogen is not replenished until the return of nutrients, this restorative process is under the control of cortisol.

True. Most tissues, including the brain, can ultimately adapt to the use of ketone bodies as a fuel source. However the brain cannot survive without glucose.

False. Glycerol can be used to produce glucose but the free fatty acids undergo beta-oxidation to produce ATP in the mitochondria.

True.

Question 48

Q

TRUE/FALSE

Insulin and growth hormone have directly opposing effects on:

A. Fat catabolism
B. Glucose utilisation
C. Fat anabolism
D. Protein anabolism
E. Glycogen production

Answer

A

True. Growth hormone causes fat breakdown.

True. Growth hormone inhibits glucose utilization, whereas insulin stimulates glucose absorption.

True. Insulin stimulates fat deposition.

False. Both insulin and growth hormone promote protein synthesis.

True. Insulin stimulates glycogen deposition, whereas growth hormone encourages glycogenolysis.

Question 49

Q

TRUE/FALSE

Consequences of starvation include:

A. Increased brain uptake of glucose
B. Reduction of the respiratory quotient
C. Elevated blood glucagon levels
D. Increased urinary nitrogen output
E. Development of metabolic alkalosis

Answer

A

False. Glucose supply to the brain is a priority in starvation as it is largely dependent on glucose as an energy substrate. The brain can however metabloise ketones.

True. As metabolism switches to the burning of fats the respiratory quotient drops towards 0.7.

True. Glucagon levels go up as the body enters a catabolic phase with increased glycogenolysis.

True. Increased protein breakdown leads to increased urinary nitrogen excretion.

False. The accumulation of acetyl-CoA leads to ketoacidosis, not alkalosis.

Question 50

Q

TRUE/FALSE

Considering ketone bodies:

A. The majority of amino acids can be converted into acetoacetate
B. The liver converts fatty acids into acetoacetate for transport to other parts of the body
C. Ketosis can arise from a diet composed almost entirely of fat
D. Citrate availability limits entry of acetyl-CoA into the citric acid cycle
E. Ketoacidosis causes hyponatraemia

Answer

A

True. The majority of amino acids after deaminationcan be converted into acetyl-CoA from which acetoacetate can be formed.

True. Fatty acid degradation occurs largely in the liver where aceyl-CoA is formed leading to acetoacetate production. This is transported at low levels but with efficient flux to the rest of the body.

True. Ketosis, the presence of excessive levels of acetoacetate, beta-hydroxybutyrate or acetone in the blood can arise in starvation, diabetes mellitus or in a very high fat based diet.

False. Sufficient oxaloacetate is needed to receive acetyl-CoA into the citric acid cycle.

True. Ketoacids are easily excreted by the kidney but being strong acids they are excreted combined with Na+ from the extracellular fluid. The resultant hyponatraemia leads to an increased acidosis beyond that occasioned by the direct rise in ketoacid levels.

Question 51

Q

TRUE/FALSE

The following hormones are secreted by the anterior pituitary gland:

A. Thyrotropin releasing hormone
B. Growth Hormone
C. Vasopressin
D. Lutenising hormone
E. Prolactin

Answer

A

False. This is produced by the hypothalamus to stimulate release of TSH by the anterior pituitary.

True.

False. This is secreted by the posterior pituitary which is physiologically very different to the anterior part of the gland.

True.

The anterior pituitary synthesisis the following hormones: prolactin, growth hormone (GH), adrenocorticotrophic hormone (ACTH), thyroid stimulating hormone (TSH), lutenising hormone (LH) and follicle stimulating hormone (FSH). The release of these hormones is dependent on stimulation from the hypothalamus via a complex portal vascular system.

Question 52

Q

TRUE/FALSE

Aldosterone:

A. Is a glucocorticoid
B. Is synthesised in the zona glomerulosa of the adrenal medulla
C. Secretion is stimulated by hyperkalaemia
D. Causes sodium retention predominantly in the loop of Henle
E. Increases intracellular cAMP

Answer

A

False. It is a mineralocorticoid.

False. It is synthesised in the zona glomerulosa of the adrenal CORTEX.

True. And by angiotensin II and ACTH.
False. This occurs primarily in the DCT.

False. It acts on intracellular receptors to propduce specific gene transcription. cAMP concentrations are altered due to agonist effects on extracellular 2nd messenger receptors.

Aldosterone is produced by the zona glomerulosa of the adrenal cortex in response to stimulation by angiotensin II, ACTH and a rise in serum potassium. It is a mineralocorticoid with 21 carbon atoms. It causes sodium retention and potassium loss at the DCT. Aldosterone levels are high in Conn’s syndrome and low in Addison’s disease.

Question 53

Q

TRUE/FALSE

Insulin:

A. Secretion produces anabolic conditions
B. Is a positive inotrope
C. Is secreted by alpha cells within the Islets of Langerhans
D. Causes triglyceride breakdown
E. Secretion is stimulated by somatostatin

Answer

A

True.

False. It is secreted by beta cells.

False. It causes triglyceride formation and fat deposition.

False. It is inhibited by somatostatin (as is glucagon).

Insulin is a peptide hormone secreted by beta cells within the Islets of Langerhans in the Pancreas. Secretion is stimulated by a rise in plasma glucose, parasympathetic release of Ach, beta 2 adrenoceptor stimulation (adrenaline) and amino acids arginine and leucine. Release is inhibited by low glucose concertrations, noradrenaline (alpha 1) and somatostatin.

Question 54

Q

TRUE/FALSE

Regarding the posterior pituitary gland:

A. It is connected to the hypothalamus by a portal vascular system
B. It is responsible for synthesis of vasopressin and oxytocin
C. It produces lipid soluble hormones
D. Release of vasopressin is stimulated by an increase in osmolality
E. Vasopressin acts on aquaporin channels within the distal convoluted tubule

Answer

A

False. It communicates with the hypothalamus via specialised neurons. The ANTERIOR pituitary is connected to the hypothalamus via a portal vascular system.

False. Vasopressin and oxytocin are stored in the posterior pituitary but synthesised in the aforemetntioned specialised hypothalamic neurons.

False. They are peptide hormones and are water soluble, not lipid soluble.

True. Vasopressin is ADH. Increasing osmolality stimulates ADH release to produce water retention.

False. ADH acts primarily at V2 receptors in the collecting duct to upregulate aquaporin channels and resorb water. It has a minor role at the DCT

Question 55

Q

TRUE/FALSE

Regarding the renin angiotensin aldosterone system:

A. Renin is secreted by the macula densa
B. Angiotensin I is converted to angiotensin II in the lungs
C. Angiotensisn II is a vasoconstrictor
D. Aldosterone is responsible for a rapid increase in renal blood flow in response to renin secretion
E. A patient taking candesartan will have less circulating angiotensin II

Answer

A

False. It is secreted by the juxtaglomerular apparatus. The macula densa detects sodium concentration at the DCT.

True. Angiotensin converting enzyme (ACE) is found here.

True. It is thought to preferentially constrict the efferent arteriole producing an increase in GFR.

False. The effects of aldosterone take hours as it works via intracellular receptors to alter gene trascription.

False. Candesartan is an angiotensin II receptor blocker. It has no effect on ACE.

Renin is secreted by the juxtaglomerular cells in response to signals from the macula densa which detects a decrease in sodium concentration at the DCT. Renin stimulates conversion of angiotensinogen to angiotensin I, which is converted to angiotensin II (a2) by ACE in the lungs. A2 causes vasoconstriction of the efferent arteriole and stimulates release of aldosterone from the adrenal cortex.

Question 56

Q

TRUE/FALSE

In response to trauma the following will occur:

A. Increased plasma glucose concentration
B. Increased aldosterone secretion
C. Increased ACTH production in the anterior pitutary
D. A rise is serum glucagon secretion
E. Sodium retention as a result of vasopressin action on the DCT

Answer

A

True. Due to the inhibtion of insulin production and stimulation of glucagon production by the sympathetic nervous system resulting in mobilisation of glucose.

True. Part of the stress response is aldosterone secretion resulting in sodium and water retention.

True. Part of the stress response.

True. Sympathetic stimulation causes release of glucagon to mobilse glucose stores.

False. Vasopressin is released but it causes retention of water in the collecting duct

Question 57

Q

TRUE/FALSE

Adrenaline:

A. Is produced in the central part of the adrenal gland
B. Causes bronchoconstriction
C. Causes a rise in blood glucose levels
D. Acts on alpha adrenoceptors
E. Causes miosis

Answer

A

True. Anatomically the adrenal medulla is found in the centre of the gland.

False. It causes bronchodilatation.

True. Though adrenaline does stimulate a small amount of insulin release, overall it inhibits insulin secretion and stimulates glucagon therefore raising blood glucose levels.

True. It does, although it has greater effect on beta. Pharmacologically, higher doses are needed to produce alpha effects.

False. It causes mydriasis.

Adrenaline is a post gangionic neurotransmitter in the sympathetic nervous system and is a circluating hormone produced by the adrenal medulla. It acts on both alpha and beta adrenoceptors but predominantly beta to produce vasodilation, bronchodilation, tachycardia, increased contractility, hypertension, mydriasis and increased glucose concentration.

Question 58

Q

TRUE/FALSE

The following are secreted by the adrenal cortex:

A. Noradrenaline
B. Aldosterone
C. Testosterone
D. Renin
E. Adrencorticotrophic hormone

Answer

A

False. This is secreted by the adrenal medulla.

True. This is secreted by the Zona glomerulosa.

True. The majority of testosterone is sectred by the testes or ovaries but roughly 5% comes from the adrenal cortex.

False. This is secreted by the juxtaglomerular apparatus in the kidney.

False. This is secreted by the pituitary, stimulating glucocorticoid and mineralocorticoid production.

The following hormones are sectreted by the adrenal cortex: aldosterone (zona glomerulosa), cortisol and corticosterone (zona fasciculata) and androgens such as testosterone, dihydrotestosterone and androstenedione (zona reticularis)

Question 59

Q

TRUE/FALSE

Vasopressin:

A. Is secreted by the hypothalamus
B. Is a peptide hormone
C. Secretion is stimulated by increased plasma osmolality
D. Plasma levels are high in diabetes insipidus
E. Causes selective reabsorbtion of water in the distal convoluted tubule

Answer

A

False. It is synthesised in the hypothalamus but secreted into the circulation by the posterior pituitary.

True. It is a monopeptide hormone.

True.

False. Plasma levels of vasopressin are low in DI causing increased water loss via the kidneys.

False. Though it may have a small role at the DCT vasopressin causes selective reabsorbtion of water via aquaporin channels in the collecting duct

Question 60

Q

TRUE/FALSE

Regarding catecholamines:

A. Noradrenaline is synthesised by removal of a methyl group from adrenaline
B. The rate limiting step in catecholamine synthesis is conversion of L-Dopa to Dopamine
C. Isoprenaline is synthesised in the adrenal medulla
D. Phaeochromocytomas commonly secrete more adrenaline than noradrenaline
E. Phaeochromocytomas is treated with beta blockers as a first line

Answer

A

False. Noradrenaline is a precursor of adrenaline, so, adrenaline is synthesised by the addition of a methyl group to noradrenaline.

False. The rate limiting step is the hyroxylation of tyrosine

False. Isoprenaline is a synthetic compound of similar structure to adrenaline.

False. They most commonly secrete predominantly noradrenaline, though they can be predominanty adrenaline or dopamine secretors.

False. This could result in unoppsed alpha stimulation by the excess noradrenaline causing profound vasoconstriction.

Question 61

Q

TRUE/FALSE

During pregnancy progesterone is responsible for the following changes:

A. Smooth muscle relaxation
B. Increased motility within the GI tract
C. An increase in basal temperature
D. Bronchodilatation
E. Generalised vasoconstriction

Answer

A

True.

False. It causes decreased GI motility .

True. Progesterone is thermogenic.

True.

False. Progesterone causes generalised vasodilatation.

Progesterone is responsible for most of the hormonally mediated changes occuring during pregnancy including: smooth muscle relaxation, vasodilatation, bronchodilatation, renal tract dilatation, decreased GI motility and constipation.

Question 62

Q

TRUE/FALSE

Cardiovascular changes during pregnancy:

A. Blood volume increases by approximately 25% at term
B. During pregnancy there is an increase in red cell volume with a decrease in haematocrit
C. Cardiac output increases as a result of increased heart rate
D. There is a decrease in blood pressure during normal pregnancy
E. Aorto caval compression becomes clinically significant at term

Answer

A

False. Blood volume increases by 45 - 50%.

True. Although there is an increase in red cell mass, there is a greater increase in plasma volume resulting in a net decrease in haematocrit.

False. Cardiac output increases predominantly as a result of increased stroke volume.

True. Despite the increase in cardiac output, vasodilatation leads to a decrease in systemic vascular resistance and drop in BP.

False. Aortocaval compression can occur from 20 weeks gestation onwards.

There are many cardiovascular and haemodynamic changes during pregnancy, the main ones are: increased cardiac output due to an increase in stroke volume, an increase in red cell volume and plasma volume and a decrease in systemic vascular resistance.

Question 63

Q

TRUE/FALSE

Respiratory changes during pregnancy:

A. PaCO2 is decreased to approximately 4 kPa during the first trimester
B. Funtional Residual Capacity is increased by 20% at term
C. Oxygen consumption remains the same as pre-pregnancy levels
D. Minute ventilation increases during pregnancy
E. Progesterone and oestrogen both act as respiratory stimulants

Answer

A

True. The desired PaCO2 is reset to 4 kPa as a result of progesterone. This leads to a respiratory alkalosis.

False. FRC is decreased to 80% of normal. This leads to airway closure and rapid desaturation in the supine position during the latter stages of pregnancy.

False. The requirements of a growing fetus increase oxygen consumption to 35% above pre-pregnancy levels.

True. Leading to the aforementioned respiratory alkalosis.

True.

Question 64

Q

TRUE/FALSE

Gastrointestinal changes during pregnancy:

A. Lower oesophageal sphincter tone is increased to combat increased gastric motility
B. Intragastric pressure rises as a mechanical consequence of the enlarging uterus
C. Heartburn is suffered by roughly half of all pregnant women
D. Diarrhoea is common during pregnacy
E. Rapid sequence induction is required for general anaesthesia from the start of the 3rd trimester

Answer

A

False. Wrong on both counts. LOS tone is decreased as a result of smooth muscle relaxation. Gastric emptying is thought to remain unchanged (unless opiods have been given).

False.

False. Heartburn is suffered by most women (75-85%) as a result of decreased LOS tone.

False. The opposite is true - smooth muscle relaxation within the gut leads to constipation.

False. RSI is required from the start of the 2nd trimester as that is when LOS tone decreases and reflux becomes common.

Answer 65

A

True. This is the reason for their use

False. Ergometrine (combined with syntocinon to form syntometrine or given alone to produce uterine contraction) reliably causes vomiting.

False. Ergometrine however should not as it causes a rise in BP.

True. They must therefore must be given slowly with caution.

True. They are routinely given after delivery of the baby to contract the uterus and reduce bleeding. Do not give it prior to delivery as it could result in profound fetal distress (paticularly hazardous during LSCS for twins!).

Oxytocics (such as syntocinon) are given to induce labour, to those in labour making slow progress, and after delivery of the fetus at C-section to ensure uterine contraction and reduce intrauterine bleeding

Answer 66

A

True. Morphine is lipid solube and crosses the placenta - therefore babies delivered soon after high dose IV morphine may have respiratory depression.

False. These are large polar molecules therefore not lipid soluble and not able to cross the placenta.

False. Glycopyrrolate is a quaternary amine - therefore charged and unable to cross the placenta.

True. Crosses the placenta and is teratogenic, therefore not given during pregnancy.

True. Less protein binding than bupivicaine therefore more crosses the placenta. Also subject to ion trapping as a result of the lower pH within the fetus.

Answer 67

A

True.

False. Nitrous has no effect on uterine tone making it useful during general anaesthesia for C-section.

True.

Tocolysis is the relaxation of uterine smooth muscle as a result of administration of a drug. The following drugs cause tocolysis: salbutamol, terbutaline, ritodrine, volatile agents, magnesium and GTN.

Answer 68

A

True. Tocolysis is the relaxation of uterine smooth muscle as a result of administration of a drug. The following drugs cause tocolysis: salbutamol, terbutaline, ritodrine, volatile agents, magnesium and GTN.

True. It’s an agonist at alpha 1 adrenoceptors, 5HT and dopaminergic recptors. It is used to aid delivery of the placenta or help gain control of PPH with an atonic uterus. Causes hypertension and should not be used in pre-eclampsia.

True. Examples include carbaprost and haemabate. Side effects include bronchoconstriction, tachycardia and hypotension.

False. This relaxes the uterus

False. This also relaxes the uterus

Answer 69

A

True.

False. It occurs in 5-6% of pregnancies.

False. They should be terminated by magnesium which should then be continued and the fetus delivered as soon as possible.

False. They may occur up to a week after delivery.
True. Platelets must be checked regularly during labour.

Pre-eclampsia is a disorder characterised by hypertension and proteinuria (oedema is no longer a diagnostic requirement). It may progress to eclampsia (fitting) or HELLP syndrome (haemolysis, elevated liver enzymes, low platelets) or both

Answer 70

A

False. The guidelines from the CMACE report state that patients with platelets of 80 or less are at increased risk of developing an epidural haematoma.

False. Bacteraemia is a relative but not absolute contraindication.

True. Using a tuohy needle to push infection into the epidural space could lead to an epidural abscess and paralysis.

False. Some would say this is an indication rather than contraindication - a good working epidural could save you from a crash GA section in an obese patient.

False. Anatomical abnormalities such as spina bifida may make placement of an epidural impossible, but they are not absolute contraindications.

Absolute contraindications to epidural are: Patient refusal, allergy to local anaesthetic, infection (cellulitis) over the site of placement, coagulopathy, raised itracranial pressure, profound hypovolaemia. Relative contraindications include: bacteramia, nerological disorders (eg MS, syringomyelia), fixed cardiac output state (eg aortic stenosis, HOCM), previous spinal surgery, anatomica; abnormalities (eg spina bifida)

Answer 71

A

True. Renal blood flow is usually 25% of cardiac output, and is maintained by autoregulation, whilst mean arterial pressure remains in the range 80-200 mmHg

True. Capillaries close to the boundary of the cortex and medulla loop into the medulla and form the vasa recta. These surround the Loop of Henle.They are the only blood supply to the medulla.

False. Macula densa cells are located in the distal convuluted tubule

True. Autoregulation even occurs in the dennervated kidney

False. Renal oxygen consumption is only approximately 18 mls/min

Answer 72

A

False. Each kidney contains approximately 1 million nephrons

True. The cells of the proximal convuluted tubule have brush borders. The distal tubular cels are similar to those of the tick ascending limb of the loop of Henle.

False. Proximal tubular cells are particulary rich in mitochondria

False. All nephrons possess a Loop of Henle. 20% will be juxtamedullary

True. The Bowmans capsule surrounds the glomerular capllaries and collects filtrate.

Answer 73

A

True. The renal system is the only system where capillaries drain into efferent arterioles, and then into peritubular and long vasa recta capillaries again.

False. 90% of the blood entering the kidneys supplies the cortex. It has a high blood flow-500 ml/min per 100 g of tissue. It has a low arteriovenous difference of approximately 2%.

False. NSAID’s do not influence GFR under normal circumstances but can cause significant loss of function if there is effective loss of circulating volume from any cause. PGI2 and PGE2 are released in hypovolaemia and may cause vasodilation helping prevent the kidney from ischaemic damage

True. The symptoms of uraemia occur late in the loss of renal function, and are caused by retained toxic products. They are non specific and include anorexia, nausea, vomiting, lethargy, poor sleep, pruritus

False. The normal renal blood flow is about 22-25% of cardiac output, approximately 1200 mls/minute.

Answer 74

A

True. Sodium is actively transported out of all parts of the renal tubule except the thin portion of the Loop Of Henle. Sodium is pumped from tubular cells into the interstitium by the sodium-potassium-ATPase pump

False. Reabsorption of bicarbonate, chloride, glucose, sodium and potassium occurs in the proximal tubule.

True. Glucose is normally completely reabsorbed in the proximal tubule. If the renal threshold for glucose is exceeded, glucose will appear in the urine.

True. Up to 70% of filtered water is reabsorbed in the proximal convuluted tubule

False. Aldosterone mainly acts in the distal tubule by regulating sodioum reabsorption. Water then follows passively.

Answer 75

A

True. Ammonia is produced in tubular cells by metabolism of glutamine.Its main role is in the buffering processes promoting the excretion of hydrogen ions.

False. Glomerular filtration is partly determined by molecular size, charge and protein binding.

True. In health, large molecules do not pass through the glomerular membrane. Any protein molecules that do are taken up by pinocytosis at the luminal membrane

True. 99% of glucose is reabsorbed by a saturable co-transport mechanism in the proximal tubule

False. Hydrogen ions are buffered intraluminally by phosphate, not bicarbonate ions.

Answer 76

A

True. There is a tubular transport maximum for glucose and it is 380 mg/minute.

False. The renal threshold for glucose is 11 mmol/L

False. Glucose is co transported with sodium

False. Glucose reabsorption is in the proximal convoluted tubule

True. Glucose has a tubular transport maximum that is not exceeded at normal plasma glucose concentrations

Answer 77

A

True. When less filtrate reaches the macula densa, sodium concentration around the cells is reduced. This is detected by the macula densa cells and an increase in rennin secretion is triggered

False. Renin is released from juxtaglomerular cells located in the wall of the afferent arteriole

True. Renin is released in response to the low cardiovascular pressures which occur in hypotension

True. Renin release is increased in response to beta-1-receptor stimulation

False. Release is decreased by antidiuretic hormone which acts to conserve sodium and water

Answer 78

A

False. 3 sodium ions are pumped outwards for 2 potassium ions inward.

False. In primary active transport, energy is imparted which allows the substance being transported to be moved against its electrochemical gradient

True. When 3 sodium ions and 2 potassium ions bind to the carrier protein, the ATPase function of the protein is activated

True. Gradients are set up via the sodium-potassium ATPase pump to allow the reabsorption of sodium ions via secondary active transport.

False. 3 sodium ions are pumped out for 2 potassium ions pumped inward.

Answer 79

A

False. Sodium chloride ingestion increases plasma osmolality and will decrease aldosterone prouction. One of the main roles of aldosterone is in sodium reabsorption

True. Hypovolaemia causes renin release, and thus angiotensin II release. This causes aldosterone release, with the ultimate effect of increasing sodium and water reabsorption

True. Aldosterone increases sodium reabsorption from the gut, sweat and saliva.

True. Aldosterone stimulates the production of potassium channels in the luminal membrane of the cortical collecting duct.Potassium is lost through these.

False. Aldosterone is the main determinant of sodium reabsorption

Answer 80

A

True. Para amino hippuric acid (PAH) is 90% cleared by the kidneys from the plasma. PAH clearance is therefore used to estimate RPF. The amount of PAH still in the blood can be corrected for.

True. Inulin is almost completely cleared. Its rate of excretion is very close to its filtration rate. Glucose is reabsorbed up to its transport maximum.

True. A majority of filtered water is reabsorbed by the renal tubules

False. If a substance is actively reabsorbed its clearance must be below that of inulin

True. An ideal substance for the measurement of GFR will be freely filtered, neither secerted or reabsorbed, nor metabolised

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