In a normal heart

a)      The right coronary artery lies in the atrioventricular groove

b)      The coronary sinus lies in the anterior atrioventricular groove

c)      The venae cordis minimae drain directly into the cardiac cavities

d)      There is increased forward flow through the coronary arteries during ventricular systole

e)      The blood supply to the interventricular septum arises from the anterior descending branch of the left coronary artery.

 

Concerning the foetal circulation

a)      It is possible for vena caval blood to each the aorta without going through the left ventricle or left atrium

b)      The pO2 in the descending aorta is less than in the ductus arteriosus

c)      The foramen ovale closes at birth because of increased left atrial pressure

d)      At birth flow in the ductus arteriosus reverses because of decreased pulmonary resistance

e)      Umbilical arterial blood has a higher PO2 than umbilical venous blood

 

The following are produced in the hypothalamus

a)      Prolactin

b)      T.R.F

c)      T.S.H

d)      Vasopressin

e)      A.C.T.H

 

 

 

Insulin and growth hormone have directly opposing effects on

a)      Fat catabolism

b)      Glucose utilisation

c)      Fat anabolism

d)      Protein anabolism

e)      Glycogen production

 

The following influence aldosterone secretion

a)      Surgical stress

b)      Total sodium intake

c)      Renal ischaemia

d)      Angiotensin

e)      Plasma potassium concentration

 

Parathormone

a)      Increases plasma calcium concentration

b)      Increases bone resorption of calcium

c)      Increases urinary phosphate loss

d)      Is a polypeptide

e)      Causes phosphaturia

 

 

 

 

 

Carotid body receptors

a)      Have a higher blood flow gm for gm than the brain

b)      Have baroreceptors activity

c)      Respond to changes in oxygen content of the blood

d)      Respond to changes in pH

e)      Are not affected by carotid endarterectomy

 

Concerning liver blood flow

a)      Portal venous pressure is less than 20 mmHg.

b)      50% is from the hepatic artery

c)      Total flow is 1.5 1/min

d)      The liver derives most of its oxygen needs from  the portal supply

e)      The oxygen  saturation of portal blood is 95%

 

Sodium concentration is less than 50mmol in

a)      Oedema fluid

b)      Interstitial fluid

c)      Interstitial fluid

d)      A 24 Hr urine sample

e)      Cerebrospinal fluid

 

 

 

 

 

Cardiac output is increased during:-

a)      Stimulation of sympathetic cardiac nerves

b)      Tension pneumothorax

c)      Acclimatization to high altitude

d)      Hypovolaemic shock

e)      Stimulation of the sinus nerve

 

Pulmonary vascular resistance:

a)      Is increased in hypoxia

b)      Is decreased by a low pH

c)      Can be measured using a flow-directed balloon catheter

d)      Is increased by isoprenaline

e)      Is decreased by 5-HT

 

One or more prostaglandins:

a)      Are peptides found in prostatic secretions

b)      Dilate the bronchi

c)      Stimulate uterine contractions

d)      Raise the intracranial pressure

e)      Affect platelet function

 

 

 

 

 

In the control of body temperature:

a)      Shivering is a spinal reflex

b)      Energy from brown fat is released via beta adrenergic receptors

c)      Brain amines play and important role

d)      PGEI may cause pyrexia

e)      Control is independent of higher centres

 

In the control of respiration:

a)      Hypoxic drive originates in the peripheral chemoreceptors

b)      There is no significant hypoxic drive in a normal subject breathing air at sea level.

c)      The response of CO2 is linear over the normal range

d)      The increased drive in exercise is due to incomplete oxygen equilibration in the pulmonary capillaries

e)      The gasping respiration of shock is a baroreceptor reflex

 

Gas content of blood:

a)      The normal venous PO2 is approximately 5.2 kPa (40 mmHg)

b)      The normal venous oxygen saturation is 75%

c)      At sea level and breathing air, 0.6 ml oxygen are dissolved in 100 ml blood containing 15 gm haemoglobin/d1

d)      Nitrogen is only carried in arterial blood in the dissolved form

e)      At a PO2 of 5.2 kPa (40 mmHg) and at sea level, 47 ml CO2 are combined with haemoglobin at a concentration of 15 gm/dl

 

 

 

The effect of Hypercarbia upon the oxyhaemoglobin dissociation curve is :

a)      To shift the curve to the left

b)      To reduce the affinity fo haemoglobin for oxygen

c)      Also temperature dependent

d)      Masked by decreases in 2,3-DPG

e)      Enhanced in anaemia

 

Regarding the ECG

a)      The t wave represents ventricular depolarisation

b)      The standard ECG is recorded at 50mm/sec.

c)      Q-T interval is inversely related to heart rate.

d)      S-T elevation occurs in pericarditis and is convex upward.

e)      Information regarding muscle mass may be obtained

 

In the cardiac cycle

a)      Atrial contraction is more important at slow, than at fast heart rates.

c)      The first heart sound is caused by an abrupt rise in intraventricular pressure and closure of the A-V valves.

d)      The fourth heart sound occurs on atrial contraction with flow through the A-V valves.

e)      PCWP normally equates with LAP.

f)        The apex beat lies in the 5th ICS in the MCL

 

 

 

 

In the working  myocardium

a)      Resting membrane potential is – 60v.

b)      There is an increase in Na permeability during phase 0

c)      Ca2+ enters the cell during phase 2.

d)      ATP is bound and split by myosin ATPase.

e)      No oxygen debt is incurred.

 

The following are correct?

a)      (H+) =40 nmoml/litre if bicarbonate = 18 and PCO2= 40 mm---

b)      pH=log(H+)

c)      The pK of bicarbonate is 5.1

d)      pH=pK +log (HC03-)

       H2C03

      e) Ph is directly proportional to the concentration of hydrogen ions

 

With acute exposure to Fi02 of 10% you would expect

a)      Respiratory alkalosis

b)      An increase in cardiac output

c)      Alkaline urine

d)      Increased arterial PCO2

e)      Pulmonary vasoconstriction

 

 

 

 

Concerning compliance

a)      Lung compliance is les than total compliance

b)      Dynamic compliance is less in a paralysed patient

c)      In IPPV tidal volume depends only on compliance

d)      Compliance is directly proportional to V/Q ratio

e)   Compliance in a 5 year old is double than that of a 20 year old.

 

The following can be determined from the volume  pressure curve

a)      Work of breathing

b)      FRC

c)      Compliance

d)   Static Compliance

e)   Dynamic Compliance

 

Breathing in the lateral position

a)      Ventilation is greater in the upper lung

b)      PO2 is greater in the lower lung

c)      V/Q ratio in the lower lung is increased

d)      Perfusion is greater in the upper lobe.

e)   V/Q is about 1 near right pulmonary artery

 

 

 

 

 

Closing volume

a)      Is 10% of a fit  young persons vital capacity

b)      Varies with extremes of age

c)      Increases with supine position

d)      Increases with obesity

e)   By law is more than closing capacity

 

The coronary circulation

a)      90% of venous blood passes through the coronary sinus into the RA

b)      Left coronary flow is greatest mid systole

c)      Auto-regulation occurs between the mean pressure of 40 and 220 mmHg.

d)      ADP is largely responsible for auto-regulation

e)      Isoflurane is the least potent of the inhalation agents in reducing myocardial contractility.

f)        Myocardial oxygenation increases via increasing oxygen extraction.

 

With myocardial   contraction

a)      Energy of contraction is inversely proportional to muscle fibre length.

c)      Increased diastolic filling increases stroke volume

d)      VEDP is used as a measure of EDV

e)      LV performance curves plot LVSW v LEVDP

f)        An LVEDP of 12 cmH20 could be normal

 

 

 

 

Regarding Cardiac Output.

a)      10% supplies the coronary circulation at rest

b)      CO=BP*PVR

c)      Stroke volume  is more important than HR in increasing CO in a young healthy adult.

d)      Using a thermistor tipped PAFCCO is  equivalent to the area under the cooling  curve.

e)      Inotropes and vasodilators may increase CO.

 

The neuromuscular junction.

a)      The pre-post junctional gap is 100-200 A.

b)      Ach is released a quanta, proportional to the third power of the calcium concentration.

c)      Pre-junctional receptors control Ach synthesis

d)      MEPPs are propagated

e)      Aminoglycosides are channel blockers.

 

 

Beta receptor stimulation of he heart

a)      Is predominantly beta 2.

b)      Increases myocardial contractility

c)      Increases refractory period

d)      Increases intracellular Ca2+

e)        Increases A-V conduction velocity

 

 

 

Nervous regulation of the heart

a)      Sympathetic nerve arise from T2 and T3

b)      Parasympathetic stimulation leads to a fall in CO

c)      Baroreceptor stimulation increases sympathetic tome

d)      Heart rate increase by 20/min for each deg C rise in core temp.

e)   Sympathetic stimulation increases the slope of end systolic pressure volume relationship

 

The oxy-haemoglobin dissociation curve.

a)Is left shifted by a fall in pH

b)      Position is defined by the P50 (normally 40mmHg)

c)      Is produced from the allosteric interaction of  molecular oxygen on he Hb molecule

d)      Is right shifted by an increase in temperature

e)      Is influenced by the Rapoport-Luebering  shunt

 

The tension of 02/CO2 in blood may be determined by

a)      Haldane method

b)      Van-Slyke method

c)      Polarography

d)      Gas chromatography

e)      Tonometry

 

 

 

 

Oxygen

a)      1G combines with 23ml 02

b)      1 molecule so Hb combines with four fo molecular 02

c)      is responsible for the Paul-Bert effect

d)      May be used in the treatment of pneumatosis coli

e)      Is a product fo photosynthesis

 

Pulmonary blood volume

a)      Is normally 20% of TBV

b)      250ml. Blood is within pulmonary capillaries in an adult

c)      Acts as a reservoir

d)      Decreases in inspiration

e)      Increases with mitral stenosis

 

Parathyroid hormone

a)      Raises plasma ionised calcium concentration

b)      Increases osteoclast activity

c)      Increases the reabsorption of phosphate

d)      Decreases production of 1, 25 DiOH CC.

e)      Increases Alkaline Phosphatase

 

 

 

 

 

Creative Kinase (CPK)

a)      Is found in heart muscle, kidney and skeletal muscle.

b)      Increases in hypothyroidism

c)      Reduces in alcoholism

d)      Increases with parturition

e)      May increase post CVA.

 

Iron

a)      Total body iron is 150mmol (8g).

b)      70% is in the RBC.

c)      Is essential for oxidative phosphorylation

d)      Is stored in he reticuloendothelial system

e)      Parenteral therapy may easily lead to iron overload.

 

Compensatory mechanisms for a primary acidosis include:-

a)      Hyperventilation

b)      Increased urine pH

c)      Elevated CSF bicarbonate

d)      Decreased carbonic anhydrase activity within the renal tubular cells

e)      Bicarbonate excretion to control urine pH.

 

 

 

 

 

Nerve conduction

a)      At the height of the action potential the membrane potential approaches the equilibrium potential balancing the ions on the tow sides of the membrane

b)      The duration of the refractory period limits transmission frequency

c)      Is fastest in myelinated fibres

d)      Saltatory conduction involves sodium and chloride permeability alone.

e)   Speed is always directly proportional to the thickness of the nerve fibres

 

Potassium balance:

a)      Is acutely regulated by changes in concentration across cell membranes

b)      Plasma levels are acutely elevated by an alpha adrenergic affect

c)      Hyperkalaemia decreases glucagon secretion

d)      Intracellular alkalosis decreases serum potassium

e)   90% of the total body potassium is intracellular

 

The following statements are true of the oxyhaemoglobin dissociation curve:

a)      The p50 is approximately 3.6 kPa (27 mmHg)

b)      The curve moves to the right if there is Hypercarbia

c)      The curve moves to the left if there is acidaemia

d)      The p50  is decreased by a raised PaCO2

e)      The steepest  part of the curve is below the normal  venous point.

 

 

 

 

 

The following changes occur in acclimatization at altitude;

a)      The kidneys excrete an acid urine

b)      The red bone marrow is  suppressed

c)      Cardiac output increases

d)      The haemoglobin concentration rises

e)   The shape of chest wall changes to favour pump handle movement

 

The following are true for jugular venous pressure tracings:-

a)      The ‘a’ wave is due to atrial systole

b)      The summit of the ‘v’ wave marks the beginning of  ventricular systole

c)      The ‘a-v’ interval is a guide to the conduction time of the bundle of His

d)      The ‘c’ wave is due to bulging of the artio-ventricular valves into the atrium

e)      The ‘v’ wave is due to filling of the atrium with the atrio-ventricular valves closed.

 

The following cause vasodilation of the peripheral arterial blood vessels:

a)      Thromboxane A2

b)      Endothelin

c)      Adenosine diphosphae (ADP)

d)      Nitric oxide (NO)

e)      Prostacylin

 

 

 

 

 

In decompression sickness:

a)      Bubbles of carbon dioxide form in the tissues

b)      Joint pain is   typical feature

c)      Symptoms typically begin 48 h after returning to atmospheric  pressure

d)      The condition is commoner in smokers

e)      Recompression should be rapid.

 

The following are physiological effects of hyperventilation.

a)      Increased pulmonary artery pressure

b)      Peripheral arteriolar vasodilation

c)      A shift to the left in the oxygen dissociation curve

d)      Fall in plasma potassium concentration

e)   Alakalosis

 

Saltatory conduction:-

a)      Occurs only in myelinated nerve fibres

b)      Is conduction of an action potential between schwann cell nuclei

c)      Is slowed as temperature falls

d)      Is faster in nerve fibres of larger diameter

e)   Occasionally occurs in un-myelinated nerve fibres

 

 

 

 

 

The carotid sinus:

a)      Is located at the origin of the internal carotid artery

b)      Contains receptors that are sensitive  to blood pH

c)      Is innervated by the glossopharyngeal nerve

d)      Causes peripheral vasodilation when stimulated

e)      Becomes hypersensitive, particularly in young women.

 

Adult haemoglobin:-

a)      Contains four molecules of globin

b)      Combines with carbon dioxide

c)      Combines with carbon monoxide at the same site on the haemoglobin molecule as oxygen

d)      Carries molecular rather than ionic oxygen

e)      Production is increased by direct action of hypoxia on the bone marrow

 

The QRS complex on he electrocardiogram:-

a)      Is caused by ventricular myocardial repolarisation

b)      Will normally contain a Q-wave up to half the height of the R-wave

c)      Corresponds with the phase of isovolumetric contraction

d)      Is shortened in tricyclic poisoning

e)      May be used to assess rotation of the heart along its longitudinal axis

 

 

 

 

 

Growth hormone and insulin has opposite effect in:-

a)      Carbohydrate uptake by muscle

b)      Anabolism of fat

c)      Catabolism of fat

d)      Protein synthesis

e)        Amino acid uptake

 

The following hormones are produced by the hypothalamus:

a)      Corticotrophin releasing factor

b)      Prolactin

c)      ADH

d)      TSH

e)      Growth hormone

 

Reduced FRC

a)      In the obese

b)      Assuming an upright posture

c)      Following anaesthesia

d)      Is more pronounced after upper abdominal than peripheral surgery

e)      Increased gaseous induction time

 

 

 

 

 

A decrease in arterial oxygen tension would occur with :-

a)      Old age

b)      Breathing 1% carbon monoxide

c)      Anaemia

d)      Pregnancy

e)      High attitude

 

A marked increase in ventilation would be caused by:-

a)      Breathing air containing 0.3% carbon monoxide

b)      Deceasing CSF pH

c)      A rise in the blood pH to 7.45

d)   With an increase of arterial carbon dioxide above 10 Kpa

e)   Administration of Doxapram

 

In the explosive phase of a cough

a)      Intrapleural pressure may rise to 50 mmHg

b)      There is a decrease in cerebral perfusion pressure

c)      There is a narrowing of the airways

d)      There is contraction of the diaphragm

e)   There is closure of glottis

 

 

 

 

 

Intrapleural pressure

a)      Can be measured with an oesophageal balloon

b)      Is related to diffusion of O2 into the Intrapleural space

c)      Becomes increasingly negative with increasing lung volumes

d)      Equals atmospheric pressure at FRC

e)   Is more negative at the apices because of the weight of the lungs

 

Calcitonin

a)      Is produced in parathyroid glands

b)      Is simulated by calcitonin releasing factors

c)      Inhibits bone resorption

d)      Decreases plasma calcium

e)      Influences metabolic rate

 

With 24 hour starvation there is

a)      An increase in Lipolysis

b)      Respiratory quotient increase

c)      An increase in Glucocorticoids

d)   Hypoglycemia

e)   Dehydration

 

 

 

 

 

The following are true:-

a)      Fats are predominantly absorbed in the ileum

b)      Vit K is absorbed in the stomach

c)      Bile salts are absorbed in the duodenum

d)      Iron is absorbed in the terminal ileum

e)   Water is predominantly absorbed in the rectum

 

Human erythrocytes:-

a) Contain more potassium ions than calcium ions

b) Are formed from megakaryocytes in bone marrow

c) Contain carbonic anhydrase

d) Have a life of between 110 and 130 days

e) Have average diameter of 10-12 microns (micrometers)

 

The following substances are necessary for normal erythropoiesis:-

a)      Ascorbic acid

b)      Folic acid

c)      Vitamin E

d)      Iron

e)   B12

 

 

 

 

 

Increase in 2.3 diphosphoglyceric acid (2,3, D.P.G.) concentration in red blood cell influences:-

a)      The oxygen consumption of the cells

b)      The life of stored red blood cells

c)      The oxyhaerroglobin blood dissociation

d)      The rate of carbonic acid formation by red cells

e)      The pH of the plasma

 

In a normal adult the differential white cell count includes:-

a)      Neutrophis 65 to 70 percent

b)      Lymphocytes 20 to 25 percent

c)      Monocytes 5 to 8 percent

d)      Eosinophis 0 to 4 percent

e)      Basophil 0 to 1 percent

 

Compared with intracellular fluid, the extracellular fluid contains a greater concentration of :-

a)      Sodium ions

b)      Magnesium ions

c)      Protein

d)      Hydrogen ions

e)      Bicarbonate ions

 

 

 

 

Antidiuresis for 12 or more hours leads to

a)      Retention of sodium

b)      Decrease in plasma corisol

c)      Increased renal excretion of nitrogen

d)      Increased renal excretion of potassium

e)   Decrease in plasma osmolality

 

Straining during defecation cause an immediate:-

a)      Rise in the aortic blood pressure

b)      Rise in the central venous pressure

c)      Increase in arterial PCO

d)      Fall in the intracranial pressure

e)      Increase in the intraocular pressure

                                

The following secretions of the stomach are essential

a)      HCI

b)      Persin

c)      Renin

d)      Intrinsic factor

e)      Gastrin

 

 

 

 

 

The effects of an increase in efferent vagal activity include:-

a)      Slowing of the heart rate

b)      Increased contractility of atria

c)      Decreased chronotropism

d)      Slowing of conduction between ventricles

e)      Bronchospasm

 

Hypoxaemia stimulates respiration by an action on:-

a)         The carotid sinus

b)         Central pH

c)         Central respiratory neurones

d)         The carotd and aortic bodies

e)         Central chemoreceptors in the hypothalamus

 

The alveolar carbon dioxide tension:

a)      Is normally 36-44 mm Hg

b)      Is normally 3-6 mm Hg below the arterial tension

c)      Influences the alveolar oxygen tension during air breathing

d)      Increases during pregnancy

e)      Roughly doubles when alveolar ventilation is halved.

 

 

 

 

 

Surfactant:-

a)      Increase surface tension in the alveoli

b)      Can be detected in normal amniotic fluid at term

c)      Prevents collapse of alveoli at low lung volume

d)      May be deficient in premature infants

e)      Maintains the normal permeability of the alveolo-capillary membrane

 

A healthy person exposed to an acute reduction in the partial pressure of oxygen to 50 mm Hg in the inspired air will:-

a)      Develop respiratory alkalosis

b)      Secrete more acid urine

c)      Have increased pulmonary vasoconstriction

d)      Have an increased cardiac output

e)      Have a reduction in the oxygen carrying capacity of his blood.

 

Reabsorption of glucose in the kidneys:-

a)      Occurs in the distal convoluted tubule

b)      Is directly controlled by the plasma glucose level.

c)      Is directly controlled by insulin secretion

d)      Is inhibited by phloridzin

e)      Does not require adenosine triphosphate

 

 

 

 

 

The mass of gas dissolved in a liquid at constant ambient temperature depends upon the:-

a)   Temperature of the liquid

b)      Partial pressure of the gas

c)      Diffusion coefficient

d)      Solubility of the gas in the liquid

e)      Critical temperature of the gas.

 

The oxygen dissociation curve of blood:-

a)      May be constructed by plotting the oxygen content against the oxygen tension

b)      Is shifted to the left in the foetus

c)      Is shifted to the left with raising the hydrogen ion concentration

d)      Is shifted to the right by raising the temperature

e)      Is hyperbolic in shape

 

Peripheral arterial resistance is raised by:-

a)      Injection of noradrenaline

b)      Increased stroke output

c)      Baroreceptor stimulation

d)      Hypovolemia

e)      Hyperactivity of the juxta-glomerular apparatus

 

 

 

 

 

During severe exercise the :-

a)      Oxygen saturation of mixed venous blood is 70 percent

b)      Heart rate may rise to over 150/min

c)      Pulmonary vascular resistance falls

d)      Cardiac output may reach 20-30 litres/min

e)      Venous pressure rises

 

Plasma colloid osmotic pressure:-

a)      Depends largely on plasma albumin concentration

b)      Makes a large contribution to plasma osmolality

c)      Is lower than the colloid osmotic pressure of lymph

d)      Is affected by the haemoglobin concentration in the red cells

e)      Can be raised by intravenous Mannitol

 

The normal metabolic response to an operation includes:-

a)      Antidiuresis for 12 to 24 hours

b)      Retention of sodium

c)      Decrease in plasma cortisol

d)      Increased renal excretion of nitrogen

e)      Increased renal excretion of potassium

 

 

 

 

 

Pulmonary vascular resistance may be increased by:-

a)         Hypoxia

b)         Acidawmia

c)         Exercise

d)         The valsalva manoeuvre

e)         Serotonin (5-hydroytryptamine)

 

Cardiac output:-

a)         Is the volume of blood pumped out by either ventricle in one minute

b)         Is the product of the heart rate and stroke volume

c)         Is under nervous control only

d)         May be measured by the Fick principle

e)         Falls on assuming the erect posture from the horizontal

 

The resting membrane potential of a nerve cell:-

a)      Is normally about 70 mv internally

b)      Is related to the relative concentrations of chloride inside and outside

c)      Is little altered by changing the external Na concentration

d)      Requires the presence of a sodium pump

e)      Is highly dependent on the external concentration of potassium

 

 

 

 

 

The following are true:-

a)      Fructose is a disaccharide of glucose and galactose

b)      Following a meal the blood pyruvate concentration increases.

c)      Leucine is a branched chain amino acid.

d)      Insulin is required for the production of free fatty acids from stored triglycerides.

e)      Uncoupling of oxidative metabolism occurs in brown fat.

 

The complement system plays an important role in the following:-

a)      Mantoux reaction

b)      Virus inactivation.

c)      Phagocytosis by neutrophils.

d)      IgE binding to mast cells.

e)      Neutrophil chemotaxis

 

Calcitonin is:-

a)      A peptide hormone

b)      Secreted by the parathyroid glands

c)      Inhibits osteoblast activity

d)      Is secreted following pentagastrin infusion

e)      Is functionally antagonised in its action on bone by Parathormone.

 

 

 

 

 

Ferritin

a)      Is involved in the transfer of iron across the gut wall.

b)      Is involved in he tissue storage of iron

c)      Is involved in the transfer of iron to the liver

d)      Is involved in the transfer of iron to muscles

e)      Is destroyed immediately after use.

 

The following increase on rising from lying down :-

a)      Cardiac output

b)      Renin secretion

c)      Vital capacity

d)      Dead space

e)      Central venous pressure

 

Unilateral section of the cervical sympathetic chain causes:-

a)      Nasal mucosal hypertrophy on the affected side

b)      Enopthalmos on the affected side

c)      Mydriasis on the affected side

d)      Excessive lacrimation on the affected side

e)      Failure of accommodation

 

 

 

 

 

Acetylcholine is the neurotransmitter:-

a)      At sympathetic preganglionic terminals in the adrenal medulla.

b)      At parasympathetic postganglionic terminals in the parotid gland

c)      At sympathetic postganglionic terminals in sweat glands

d)      At pupillary sympathetic dilator fibres

e)      At sympathetic ganglia

 

The following muscles are important in forced expiration:-

a)      External intercostals

b)      Internal intercostals

c)      Diaphragm

d)      Serratus anterior

e)      Abdominal muscles

 

The hepatic blood flow:-

a)      Is 1.5 L/min in normal adults

b)      40% comes from the hepatic portal vein

c)      The hepatic portal venous pressure is 80 mmHg

d)      70% of the hepatic oxygen supply come from the hepatic artery

e)      Is increased by GTN

 

 

 

 

 

Myosin

a)      Is found only in muscle cells

b)      Is composed of tropomyosin and troponin

c)      Is linked to actin by cross bridges

d)      Is surrounded by sarcoplasmic reticulum

e)      Contains an ATPase

 

In the mechanism of normal clotting

a)      Widespread tissue damage produces a substance that interferes with the process

b)      Vitamin C is necessary

c)      The normal whole blood clothing time is less than tow minutes

d)      Clot retraction is mediated by platelets

e)      Factor VI is important

 

The QRS complex of a normal ECG

a)      Is less than 0.2 seconds

b)      Has the same amplitude no matter from where it is recorded on the chest wall

c)      Is exactly synchronous with ventricular contraction

d)      May vary in amplitude with respiration

e)      Varies in duration with changes in heart rate.

 

 

 

 

 

The carotid bodies:-

a)      Have a blood flow in mls/kg/min less than that of the brain

b)      Are more sensitive to p02 than oxygen content

c)      Have a high resting oxygen consumption

d)      The afferent connections are via the vagus nerve

e)      Contain baroceptors

 

Sodium ions normally have a concentration of more than 50 mmol/L in

a)      Urine

b)      Oedema fluid

c)      Intracellular fluid

d)      Extracellular fluid

e)      CSF

 

Pregnancy is associated with a rise in

a)      Total red cell mass

b)      Protein bound iodine

c)      Cardiac output

d)      Total body water

e)      Circulating fibrinogen

 

 

 

 

 

The hypothalamus contains cells which produce

a)      Growth hormone

b)      Vasopressin

c)      Proplactin

d)      Oxytocin

e)      TSH

 

In normal arterial blood

a)      Hydrogen ion concentration equals 40 nmols/L

b)      PH equals the log of the hydrogen ion concentration

c)      The pK of the bicarbonate system is 6.1

d)      PH = pK + log (10) (HCO3-) / (H2033)

e)      The solubility coefficient for carbon dioxide is 0.03 ml / 100 ml/ mm Hg

 

The pulmonary circulation

a)      Has a mean pressure one-third that of the systemic circulation

b)      Contains 50% of the blood volume

c)      The PA occlusion pressure is equal ot the La pressure

d)      Responds to hypoxia by a decrease in its resistance

e)      The VQ ratio at the apex in the standing position is zero

 

 

 

 

 

Cerebrospinal fluid

a)      Has the same PO2 as arterial blood

b)      Protein content is the same as plasma

c)      Has the same pH as plasma

d)      Has a higher glucose content than plasma

e)      Chloride level is higher than plasma

 

Acute painful stimulation of the left foot causes

a)      Activation of the flexor muscles of the left leg

b)      Extension of the contra-lateral limb

c)      Impulses bypass the thalamus

d)      Impulses pass up the spinal cord in the contra-lateral spinothalamic tract

 

On changing posture from supine to sitting there will be

a)      A reduction in the blood volume in the lung

b)      Apical V/Q ratio in the lung will approach infinity

c)      An increase in heart rate

d)      An increase in functional residual capacity

e)         A decrease in alveolar PCO2

 

 

 

 

 

 

Total hepatectomy will lead to:-

a)      Hypoglycaemia

b)      Decreased amino acid level

c)      Decreased fibrinogen

d)      Increased urea

e)      Decreased ratio of albumin to globulin

 

Considering the action potential of a ventricular muscle cell

a)      It has a similar duration as the refractory period

b)      Shows phase 4 depolarisation

c)      The plateau is due to influx of calcium ions

d)      The refractory period and ventricular muscle contraction are of similar duration

 

A pregnant woman will have increased

a)      Blood flow to her hands

b)      Total body water

c)      Red cell mass

d)   Pulmonary Vascular Resistance

e)   Extravascular water

 

 

 

 

 

 

The anterior pituitary

a)      Produces vasopressin

b)      Has a separate portal blood supply to the posterior lobe

c)      Undergoes separate development from the posterior pituitary

d)      Has a direct neural connection with the pineal gland

e)      Contains chromophobe cells

 

Cardiac output is reduced in

a)      Hypothyroidism

b)      Response to carotid sinus stimulation

c)      Peripheral vasodilatation

d)      After a heavy meal

 

Anaemia  is clinically evident when

a)      there is over 5 g/dl of carbaminohaemoglobin

b)      Hb is less than 10 g/dl

c)      SaO2 is 90%

d)      There is 10g/100ml carboxyhaemoglobin

e)      PaO2 = 70 mmHg.

 

Myocardial contractility is increased by increasing

a)      Initial muscle fibre length

b)      Circulating catecholamines

c)      Extracellular potassium concentration

d)      Extracellular ionised calcium concentration

In forced  expiration the following muscles are active

a)      Diaphragm

b)      External oblique

c)      Internal oblique

d)      Scalenus anterior

e)      Rectus abdominis

 

Venous return to the heart is assisted by

a)      Descent of the diaphragm

b)      Increased intrathoracic pressure

c)      Unidirectional valves in the inferior vena cava

 

Absorption of:-

a)      Water in the gut is active

b)      Iron occurs in the duodenum

c)      Fat occurs in the jejunum

d)      Bile salts occurs in the ileum

e)      Sodium chloride in the  proximal renal tubule  is controlled by aldosterone

 

An increase in erythrocyte 2-3 DPG

a)      Occurs in stored blood

b)      Occurs in chronic anaemia

c)      Shifts the O2 dissociation curve in the same  direction as a decrease in pH

d)      Shifts the O2 dissociation curve in the same direction as hypothermia

e)      Increases erythrocyte oxygen consumption.

A driver breathing air at 30 m below sea level

a)      Is subjected to a pressure of 4 atmospheres

b)      Would be unconscious as a result of nitrogen narcosis while at this depth

c)      The work of breathing is increased

d)      The O2 content of arterial blood is 2-3 times normal

e)      Runs the risk of gas bubbles forming in his central nervous system at this depth.

 

An increase in resting minute volume occurs

a)      When breathing 3% CO2

b)      If PAO2 falls to 75 mmHg

c)      In a chronic anaemia with Hb of 5 g/dl

d)   In high altitude

e)   In metabolic acidosis

 

Surfactant

a)      Is a carbohydrate

b)      Diffuses out from pulmonary capillary blood

c)      Reduces pulmonary tension

d)      Production is increased in pre-term neonates

e)   Exogenous surfactant is derived from animals

 

 

 

 

 

In pregnancy

a)      There is arise in total peripheral resistance

b)      Packed cell volume increases

c)      There is a fall in plasma T3

d)      There is a fall in arterial PCI2

e)      Red cell mass increases

 

A normal adult 2 days after uncomplicated major abdominal surgery may have the following 24 hr urine results

a)      Volume 500 ml.

b)      Sodium 20 mmol/day

c)      Potassium 10 mmol/day

d)      Nitrogen 15 g/day

e)      Urea 20 mg/day

 

The following are needed for erythropoiesis

a)      Vitamin B12

b)      Angiotensin

c)      Calcitonin

d)      Pyridoxine

e)      Folic acid

 

 

 

 

 

Transferring

a)      Is involved in the direct transfer of iron from the gut  lumen to mucosal cells

b)      Involved in transfer of iron from mucosal cells to muscle

c)      Is involved in transfer of iron to and from bone marrow

d)      Is destroyed once transport has been completed

e)      Is involved in the transport of iron from the gut to iron stores

 

Anatomical dead space

a)      Is approximately 1 ml/kg

b)      Increases on rising from supine to erect position

c)      Increases with a rise in circulating adrenaline

d)      Is normally about one third of tidal volume

e)      Is increased by pneumonectomy

 

A normal 20kg child compared with an adult

a)      Has a higher total peripheral resistance

b)      Has a higher basal metabolic rate per m2 body surface area

c)      Has greater lung compliance

d)      Has a blood volume closer to ------------ than 3 1

e)      Has a mean systemic blood pressure of 65 mmHg

 

 

 

 

 

The effects of intrapulmonary shunt may be distinguished from those of V/Q mismatch by

a)      Carbon monoxide transfer

b)      The helium steady state test

c)      Calculation of the arteriovenous PO2 difference

d)      Inspiration of 100% oxygen

e)      Calculation of the A-a PCO2 difference

 

Gastric emptying time is increased by

a)      Acid in the duodenum

b)      Fat in the oesophagus

c)      Increased blood secretin concentration

d)      Increased size of meal

e)      Sympathetic stimulation

 

Histamine

a)      Is responsible for some features of the Lewis triple response

b)   Administered   Intravascularly causes an immediate rise in blood pressure

c)      Causes the secretion of an acid mucous in the stomach

d)      Is a pre-capillary vasodilator

e)   Is responsible for Anaphylactoid reactions

 

 

 

 

 

Uncompensated respiratory acidosis causes

a)      Increased plasma bicarbonate concentration

b)      Increased urinary bicarbonate excretion

c)      Increased urinary potassium excretion

d)      Raised intracranial pressure

e)      Increased pH

 

Parathormone

a)      Increases plasma calcium concentration

b)      Increases calcium resorption from bone

c)      Increases urinary phosphate excretion

d)      Is a polypeptide

e)      Secretion is regulated by plasma calcium concentration

 

In the foetal circulation

a)      Partial pressure of O2 is greater in the ductus venosus than in the ductus arteriosus

b)      Blood can get from the vena cava ot the aorta without going through left atrium or left ventricle

c)      PaO2 in aortic arch is greater than PaO2 in descending aorta

d)      Foramen ovale closure is the result of reversal of atrial pressures difference

e)      After birth, flow through the ductus arteriosus is stopped or reversed as a result of the increase in pulmonary artery pressure

 

 

 

 

Venous return is decreased

a)      After a heavy meal

b)      During exercise

c)      In anaemia

d)      By an increase in cardiac output.

e)   In congestive cardiac failure

 

The following are precursors of adrenaline:-

a)      Noradrenaline

b)      Tyrosine

c)      Isoprenaline

d)      Phenylalanine

e)      Dopamine

 

An increase in plasma renin levels occurs with increases in

a)      Angiotensin levels

b)      Extracellular sodium

c)      Extracellular potassium

d)      Renal perfusion pressure

e)      Intravascular volume

 

 

 

 

 

In body fluids:-

a)      Intracellular (K+) is greater than Extracellular (K+)

b)      Intracellular (HCO3-) is greater than Extracellular (HCO3-)

c)      Intracellular (Mg+) is greater than Extracellular (Mg+)

d)      Intracellular H2O is greater in volume than Extracellular H2O

e)      Intracellular (Na+) is greater than Extracellular (Na+)

 

A sodium concentration of over 50 mmol/l occurs in

a)      Normal saline

b)      Cerebrospinal fluid

c)      Extracellular fluid

d)      Intracellular fluid

e)      Oedema fluid

 

Cerebrospinal fluid

a)      K+ concentration is between 2.0 and 3.5 mmol/l

b)      Specific gravity is 1008

c)      Protein content is 400-600 mg/l

d)      Is produced by the arachnoid villi

e)      Is isosmotic with plasma

 

 

 

 

 

Unilateral blockade of the sympathetic chain produces

a)      Enophthalmus

b)      Miosis

c)      Conjunctival vasodilation

d)      Decreased Iacreimation

e)      Pupillary dilation

 

The following influence the absorption of an orally administered drug

a)      Pharmacological formulation

b)      Dose

c)      Intestinal pH

d)      Presystemic (hepatic) metabolism

e)      Speed of gastric emptying

 

Most group I antiarrhythmics

a)      Slow depolarisation in cardiac conducting tissue

b)      Increase action potential duration

c)      Increase the threshold of cardiac conducting tissue

d)      Have local anaesthetic action

e)      Are useful in atrial arrhythmias

 

 

 

 

 

In skeletal muscle:-

a)      Think filaments are myosin

b)      Thin filaments are action and tropomyosin

c)      Calcium binds to troponin C

d)      Energy released from hydrolysis of ATP is directly related to muscle work.

e)      At the start of contraction, calcium is released from the lateral cisterns of the sarcoplasmic reticulum

 

Total body water

a)      Constitutes 2/3 of adult body weight

b)      Can be measured by deuterium oxide

c)      Increases with age

d)      Is proportionally greater in woman than men

e)   Is proportionately greater in children than adults

 

Intrapleural pressure :-

a)      Is sub-atmospheric throughout normal breathing at rest

b)      Becomes more sub-atmospheric during inspiration

c)      Can be assessed by measurement of intragastric pressure

d)      Is higher at the base than the apex when sitting

e)      Rises above atmospheric pressure during a forced expiration against resistance

 

 

 

 

Physiological dead space:-

a)      Can be greater than anatomical dead space

b)      Remains constant when tidal volume changes

c)      Accounts for the difference in composition between alveolar and expired gas

d)      Is increased during general anaesthesia

e)      Can be calculated from tidal volume and the CO2 concentrations fo expired and alveolar gas

 

Pulmonary surfactant:-

a)      Increases surface tension

b)      Prevents segmental collapse

c)      Increases alveolar ciliary motion

d)      Aids alveolo-capillary diffusion

e)      Is increased in respiratory distress syndrome of the newborn

 

Oxygen percentage saturation of arterial blood depends on:-

a)      Alveolar oxygen tension

b)      Haemoglobin content of blood

c)      Cardiac output

d)      Arterial CO2 tension

e)      Arterial H concentration

 

 

 

 

 

Carbon dioxide:-

a)      Causes dilation of cerebral vessels

b)      Has a normal tension in arterial blood of 36-44 mmHg

c)      Affects the excitability of neurones in he reticular activating system

d)      Has a tension in mixed venous blood 6 mmHg higher than in arterial blood

e)      Displaces oxygen from haemoglobin

 

The carotid body chemoreceptors:-

a)      Are stimulated by a fall of arterial 02 tension

b)      Are inhibited by a fall of arterial pH

c)      Reflexly produce peripheral vasoconstriction

d)      Are subject to increased stimulation in the anaemic patient at rest

e)      Have a blood flow of over 1 litre/ 100 g/ minute

 

Over-ventilation  causes :-

a)      Raised arterial CO2 tension

b)      Lowered plasma ionised calcium concentration

c)      Cerebral hypoxia

d)      Decreased arterial 02 tension

e)      Increased arterial pH.

 

 

 

 

 

In the normal pulmonary vascular bed:-

a)      The mean pulmonary arterial pressure is half the mean aortic pressure

b)      The pulmonary vascular resistance is lower than the systemic vascular resistar

c)      There is always 50% of the blood volume

d)      The wedge pressure equals capillary pressure

e)      Hypoxia causes dilatation of vessels.

 

Plasma from group A blood will agglutinate:-

a)      Only group AB

b)      Only group B

c)      Group B blood and group AB blood

d)      Group AB blood, group B blood and group O blood

e)      Group B blood and group O blood

 

Antidiuretic Hormone:-

a)      Is synthesised in he hypothalamus

b)      Increases the permeability of th proximal tubules to water

c)      May be secreted in excess during stress

d)      In large doses can cause smooth muscle contraction

e)      Secretion is controlled by ICF (intraoellular fluid)

 

 

 

 

 

Cerebral blood flow:-

a)      Decreases by half when PaCO2 falls to 20 mmHg

b)      Is  auto-regulated between mean arterial pressure 40-200 mmHg

c)      Increases when PaCO2 is less than 50 mmHg

d)      Is controlled by sympathetic nervous system

e)      Is increased by a rise in hydrogen ions in the brain.

 

The following enzymes are involved in glycogenesis:-

a)      Glucokinase

b)      Phosphoglucanutase

c)      Glucose-6-phosphatse

d)      Glycogen synthetese

e)      Debranching enzyme

 

Extracellular fluid:-

a)      Contains sodium and chloride as the predominant ions

b)      Has the same osmotic concentration a sea-water

c)      Accounts for about 40% of the body weight in adults

d)      Has a lower proportion of body weight in infancy than in old age.

e)    Predominant buffer is protens

 

 

 

 

 

The velocity of nerve impulse propagation:-

a)      Increases with pressure on the nerve

b)      Increases with metabolic acidosis

c)      Increases with myelination of the nerve

d)      Increases proportionally with the diameter fo the nerve

e)      Is greater in motor than in sensory nerve

 

Concerning calcium balance:-

a)      Vitamin D increase calcium reabsorption from the gut

b)      Parathormone increases serum calcium

c)      Calcitonin reduces serum calcium

d)      Calcium absorption is reduced by glucocorticoids

e)      Calcium is mainly excreted in the urine

 

Oxygen concentration in a gas mixture may be measured by:-

a)      A severinghaus electrode

b)      A Clarke electrode

c)      Polarography

d)      The paramagnetic effect

e)      Infra-red analysis

 

 

 

 

 

Closing volume:-

a)      Is low at birth

b)      Increases from adolescence to old

c)      Always include FRC

d)      Is always higher when supine than when upright

e)      Is measured by slow expiration after a full inspiration of a marker gas.

 

Concerning acid-base balance:-

a)      The buffering power of plasma is greater in vitro than in vivo

b)      Buffering is greater if haemoglobin concentration is higher

c)      Base excess will vary with haemoglobin concentration

d)      An increase in the slope of the buffer line (i.e. steeper) means that buffering is increased

 

The following concerns pain:-

a)      Transmission occurs in the lateral spinothalamic tract

b)      Modulated at spinal level by endorphins

c)      Modified at spinal level by descending fibres from periaqueductal grey matter in the mid-brain

d)      Cerebral cortex modified the thalamic interpretation of pain.

e)      Is not associated with psychological or emotional response to noxious stimuli.

 

 

 

 

 

Physiological dead space:-

a)      Can be greater than anatomical dead space.

b)      Remains constant when tidal volume changes

c)      Accounts for the difference in composition between alveolar and expired gas

d)      Is increased during general anaesthesia

e)      May be calculated from the CO2 tensions in mixed expired gas and arterial blood.

 

Cerebral blood flow is:-

a)      Increased by Hypercarbia

b)      Decreased by blood catecholamines

c)      Decreased by the valsalva manoeuvre

d)      Increased by raising the mean blood pressure from 120 to 140 mmHg.

e)      Subject to regional fluctuations.

 

An artificially-induced reduction of body temperature of 5°C is likely to lead to :-

a)      A reduction in oxygen consumption

b)      An increase in potency of d-tubocurarine

c)      A shift of the oxygen-haemoglobin dissociation curve to the right.

d)      A fall in the output off T3 hormone from the thyroid

e)      A reduction in cerebral blood flow.

 

 

 

 

 

Methaemoglobinaemia:-

a)      Is caused by Bupivacaine

b)      May confused with oxyhaemoglobin by pulse oximeter

c)      Shifts the oxygen dissociation curve to the right.

d)      May be caused by Sodium Nitropruside

e)      Blood normally has more carboxyhaemoglobin than Methaemoglobin

 

Human albumin solution

a)      Is stored at room temperature

b)      Has at least 4.3 g of protein per 100 ml.

c)      Is used in the treatment of DIC.

d)      Has approximately 145 mmol/1 sodium

e)      Is associated with a risk of hepatitis

 

Foetal haemoglobin:-

a)      Disappears in the first month after birth

b)      has alpha and beta subunits

c)      protects against sickling in homozygous babies with Hbs.

d)      Can be present in adults.

e)      Has a lower 02 affinity than adult haemoglobin

 

 

 

 

 

A patient with a Hb of 10g/d and PO2 100 mm Hg (at normal pH PCO2 and temperature):-

a)      Will have an O2 capacity of 13.9 mls/1000 mls blood

b)      Would  have the capacity increased to 30 mls/100 mls if Hb was increased to 15 g/dl

c)      Will have a saturation of approximately 96%

d)      Will have little change in saturation if the PO2 drops to 90 mm Hg

e)      0.03 ml dissolved 02/100 mls blood.

 

The P50 value:-

a)      Is normally 2.5 Kpa

b)      Is the PO2 at which 50% saturation occurs

c)      When increased indicates a shift of the O2 dissociation curve to the ( R ) and facilitated tissue oxygenation

d)      Is increased when pH increases

e)      Is  increased by methaemoglobinaemia

 

Haemoglobin:-

a)      Contains an iron porphyrin compound in which iron in the ferrous from is reversibly oxidised

b)      In sickle cell anaemia it is Hb A which contains valine instead of glutamic acid on the B chains

c)      When fully saturated combines with 13.4 mls O2 per gram

d)      Affinity for 02 is responsible for the sigmoid shape of the 02 dissociation curve

 

 

 

The following come from the anterior pituitary:-

a)      Somatostatin

b)      Oxytocin

c)      Prolactin

d)      Thyrotropin

e)      Aldosterone

 

Which fo he following are consequences of breathing 5 M CO2 in air?

a)      There is a rise in the P002 of mixed venous blood

b)      The pH of the arterial blood rises

c)      There is an increase in alveolar ventilation

d)      The oxygen dissociation curve of haemoglobin is shifted to the left.

e)      There is a reduction in cerebral blood flow

 

The following are statements about the consequences of voluntarily increasing ventilation three fold.

a)      The alveolar P02 trebles

b)      The plasma proteins become more ionised

c)      The plasma ionised calcium level increases

d)      A fall in the plasma bicarbonate concentration of arterial blood

e)      A brief period of apnoea immediately afterwards.

 

 

 

 

 

The following reduce a total pulmonary compliance

a)      Fibrosing alveolitis

b)      Emphysema

c)      Mitral stenosis of long duration

d)      Ankylosing spondylitis

e)      Adult respiratory distress syndrome

 

The following cross placenta

a)      Aspirin

b)      Morphine

c)      Propranolol

d)   Gllycery Trinitrate

e)      Frusemics

 

The following act to block protein synthesis:-

a)      Penicillin

b)      Actinomycin D

c)      Tetracycline

d)      Chloramohenicol

e)      Trimethoprim

 

 

 

 

 

The following are true:-

a)      Cimetidine increases the effect of warfarin.

b)      Erythromycin increases the effect of Warfarin

c)      Sodium valproate increases the effect of  Heparin

d)      Rifampicin increases the effects of oestrogens

 

The following stimulate secretion of growth hormone in healthy humans:-

a)      Sometestatin

b)      Somatomeain

c)      Somatomeain 0

d)      Sleep

e)      Hyperglycaemia

 

The following reduce secretion of gastic acid and gastrin :-

a)      Cimetidine

b)      Propanthelene

c)      Carbenoxolone

d)      Sucralfate

e)      Colloidal bismuth

A patient breathing air has a Pa02 of 7.5 kPa and a PaCO2 of 3.5. These are compatible with:-

a)      Pulmonary cedema

b)      Obesity

c)      Anklyosing spondylitis

d)      Barbiturate overdose

e)      Lobar pneumonia

In normal humans, renal plasma flow:-

a)      Mostly distributed to the renal medulla

b)      Varies significantly with systemic arterial blood pressure

c)      May be calculated from para-aminohippuric acid clearance

d)      Increases in the supine position

e)      Has a close correlation with body weight.

 

Answer true or false:-

Myelinated primary afferent neurous

a)      carry nociceptive impulses

b)      Have cell bodies in the dorsal root ganglia

c)      Have polymodal specialised sensory receptors

d)      Have central terminals in Rexed lamina IV

e)      Bifurcate on entry into the dorsal horn, passing rostrad and caudal.

 

Substance ‘P’:-

Is found in the central and peripheral terminals of the primary afferent neuron

a)      Is found in the dorsal root ganglia type B cells

b)      Is not involved in pain transmission

c)      Depletion by capsaicin makes animals insensitive to pain

d)      Is released into the CSF in response to pain.

 

 

 

 

Transmitters involved in inhibiting nociceptive information include the following:-

a)      Endogenous 2opiate” peptides

b)      Inhibiting amino acids (GABA and Glycine)

c)      Noradrenaline

d)      Serotonin (5-Ht)

e)      Dynorphin

 

The A-receptor:-

a)      Is activated by the agonist fentanyl.

b)      Is activated by ht agonist – antagonist buprenorphine

c)      Mediates analgesia but not respiratory depression

d)      Is found in high concentrations in the prei-aqeducted  grey matter

 

The following are involved in transmission at autonomic ganglia:-

a)      Noradrenaline

b)      Acetyl Choline

c)      G.A.B.A

d)      Prostaglandins

e)      Adrenaline

In the normal subject the cerebral blood flow will be increased by:-

a)      An increase in the arterial pCO2 to about 60 mmHg

b)      A head-down posture

c)      An increase in systolic blood pressure from 110 mmHg to 130 mmHg

d)      Hyperventilation

e)      A rise in the arterial pO2

The blood oxygen dissociation curve is shifted to the left by:-

a)      Low temperature

b)      Low haemoglobin levels

c)      Hypoxia

d)      Acidosis

e)      Alkalosis

 

In the normal heart:-

a)      The resting potential on the outside of a muscle cell is +80 to +90 mV

b)      The time between spontaneous firing of the S-A node and the contraction of the atria is the PR interval

c)      The S-A node is located where the right atrial walls joins the superior vena cave

d)      The S-A node resting potential is more than 90 mV

e)      The QRS complex should not be longer than 0.12 sec.