RCOA Guide to the FRCA Examination The Primary (fourth edition) - Physiology

Question 1

The anterior lobe of the pituitary gland:

Synthesises vasopressin

Answer 1

False. Vasopressin, or antidiuretic hormone (ADH), is synthesised in the hypothalamus and secreted by the posterior pituitary.

Question 2

The anterior lobe of the pituitary gland:

Has important neural connections with the pineal body

Answer 2

False.

Question 3

The anterior lobe of the pituitary gland:

Develops separately from the posterior lobe

Answer 3

True. The anterior pituitary develops as an upgrowth from the primitive mouth (stomatodeum). The posterior pituitary is an extension of the hypothalamus.

Question 4

The anterior lobe of the pituitary gland:

Contains chromophobe cells

Answer 4

True. These are probably degranulated secretory cells (chromophils).

Question 5

The anterior lobe of the pituitary gland:

Has a portal blood supply independent of the posterior

Answer 5

True. The portal supply links a primary capillary plexus in the hypothalamus to a secondary plexus in the anterior pituitary (AP). Consequently, releasing and inhibitory factors secreted by the hypothalamus reach the AP in higher concentration than if they were secreted into the systemic circulation and presented to the AP via its arterial circulation.

Question 6

The glomerular filtrate normally contains:

Inulin in a lower concentration than in plasma when given to
measure glomerular filtration rate

Answer 6

False. Inulin is freely filtered at the glomerulus and will therefore be present in the same concentration.

Question 7

The glomerular filtrate normally contains:

Albumin at 5% of its plasma concentration

Answer 7

False. In the healthy kidney, the glomerulus is impermeable to large molecules. Albumin (MW 70 000 Da) is not filtered to any significant extent and the glomerular filtrate is essentially protein free.

Question 8

The glomerular filtrate normally contains:

Amino acids

Answer 8

True. Amino acids are freely filtered and filtrate concentration is equal to that of plasma. They are normally completely reabsorbed in the proximal tubule.

Question 9

The glomerular filtrate normally contains:

Glucose in a concentration equal to that in plasma

Answer 9

True. Glucose is freely filtered and completely reabsorbed in the proximal tubule unless the transport maximum is exceeded, e.g. in diabetes.

Question 10

The glomerular filtrate normally contains:

No uric acid

Answer 10

False. Uric acid is filtered at the glomerulus. It is also reabsorbed and secreted by the proximal tubule.

Question 11

The metabolic response to injury includes:

Catabolism

Answer 11

True. Following increased secretion of catabolic hormones.

Question 12

The metabolic response to injury includes:

Retention of potassium in the body

Answer 12

False. Increased aldosterone secretion promotes sodium and water reabsorption from the distal tubule in exchange for potassium excretion.

Question 13

The metabolic response to injury includes:

Hypoglycaemia

Answer 13

False. This is largely due to changes in endocrine activity outlined below.

Question 14

The metabolic response to injury includes:

Raised plasma cortisol concentration

Answer 14

True. Secondary to increased activity of the hypothalamo-pituitary-adrenal axis.

Question 15

The metabolic response to injury includes:

Increased production of epinephrine

Answer 15

True. Secondary to sympathetic nervous system activation.

Question 16

Pulmonary variables that decrease during pregnancy include:

Minute ventilation

Answer 16

False. Minute ventilation increases early in pregnancy, reaching 50% above non-pregnant values at term.

Question 17

Pulmonary variables that decrease during pregnancy include:

PaO2

Answer 17

False. This is little changed.

Question 18

Pulmonary variables that decrease during pregnancy include:

PaCO2

Answer 18

True. As a result of increase minute ventilation.

Question 19

Pulmonary variables that decrease during pregnancy include:

FRC

Answer 19

True. Caused largely by diaphragmatic elevation as the uterus enlarges.

Question 20

Pulmonary variables that decrease during pregnancy include:

Total respiratory compliance

Answer 20

True. Lung compliance remains unchanged, but chest wall compliance decreases as a result of diaphragmatic elevation.

Question 21

The cell-mediated immune response:

Provides an explanation for some auto-immune diseases

Answer 21

True. Although some auto-immune diseases are examples of hypersensitivity reactions.

Question 22

The cell-mediated immune response:

Involves peripheral sensitisation of lymphocytes

Answer 22

True.

Question 23

The cell-mediated immune response:

Causes proliferation of plasma cells

Answer 23

False. Plasma cells are B cells which have been exposed to antigen and secrete large quantities of antibody. Antibody production is a humoral response.

Question 24

The cell-mediated immune response:

Involves increased IgM synthesis

Answer 24

False. Antibody production is a humoral response.

Question 25

The cell-mediated immune response: Causes massive release of histamine

Answer 25

False. This is a feature of a type I hypersensitivity reaction.

Question 26

Ptosis results from damage to the: Oculomotor nerve

Answer 26

True. The third cranial nerve supplies the levator palpebrae superioris muscle.

Question 27

Ptosis results from damage to the: Parasympathetic supply of the eye

Answer 27

False. Interruption of the parasympathetic supply to the eye causes mydriasis, or dilatation of the pupil.

Question 28

Ptosis results from damage to the: Cervical sympathetic chain

Answer 28

True. As a result of loss of sympathetic innervation to the superior tarsal muscle. One of the features of Horner's syndrome.

Question 29

Ptosis results from damage to the: Trigeminal nerve

Answer 29

False. The fifth cranial nerve supplies the muscles of mastication and provides the sensory supply to the face.

Question 30

Ptosis results from damage to the: Supra-orbital nerve

Answer 30

False. The supra-orbital nerve, a branch of the frontal nerve, is purely sensory in function.

Question 31

In the cerebrospinal fluid of a normal individual: The reduced buffering capacity is mainly due to a lower bicarbonate concentration

Answer 31

False. This is due to a relative lack of protein in CSF.

Question 32

In the cerebrospinal fluid of a normal individual: pH is the same as that of arterial blood

Answer 32

False. Hydrogen ion concentration is slightly higher in CSF than in arterial blood.

Question 33

In the cerebrospinal fluid of a normal individual: Protein concentration is less than in plasma

Answer 33

True. CSF protein concentration is only about 0.5% that of plasma.

Question 34

In the cerebrospinal fluid of a normal individual: Chloride concentration is higher than in venous blood

Answer 34

True. In order to maintain electrical neutrality. Anionic protein concentration is less than that of blood.

Question 35

In the cerebrospinal fluid of a normal individual: Glucose concentration is higher than in arterial blood

Answer 35

False. Glucose concentration is lower in CSF.

Question 36

In the liver: Hepatic arterial blood flow exceeds portal blood flow

Answer 36

False. Portal blood flow exceeds hepatic arterial blood flow by a 2:1 ratio.

Question 37

In the liver: The bile canaliculus is at the centre of the lobule

Answer 37

False. It is at the periphery and forms a triad along with hepatic arterial and portal venous branches.

Question 38

In the liver: The portal vein contributes approximately one third of the total hepatic blood flow

Answer 38

False. Portal blood flow exceeds hepatic arterial blood flow by a 2:1 ratio.

Question 39

In the liver: Venous pressure normal exceeds 20 mmHg

Answer 39

False. Venous pressures as high as this are pathological (portal hypertension). Normal is below 10mmHg.

Question 40

In the liver: The oxygen tension is at the lowest at the centre of the lobule

Answer 40

True. At the periphery of the lobule, portal venous and hepatic arterial blood mix to flow along sinusoids towards the centre of the lobule. The centre is most vulnerable in low perfusion states or hypoxia (centrilobular necrosis).

Question 41

Consequences of 24 hours starvation include: Increased brain uptake of glucose

Answer 41

False. This is unchanged.

Question 42

Consequences of 24 hours starvation include: Reduction of the respiratory quotient

Answer 42

True. The respiratory quotient, RQ, is the ratio of the volume of carbon dioxide produced to oxygen consumed. When only glucose is metabolised, C6H12O6 + 6O2 → 6CO2 + 6H2O, the RQ is one. RQ decreases during starvation as alternative, more reduced, oxygen inefficient, energy sources are used. Eg fat.

Question 43

Consequences of 24 hours starvation include: Elevated blood glucagon concentration

Answer 43

True. In order to promote gluconeogenesis.

Question 44

Consequences of 24 hours starvation include: Increased urinary nitrogen output

Answer 44

True. Glucose production switches from glycogenolysis to gluconeogenesis from non-carbohydrate sources. Amino acids are mobilised from muscle and are deaminated during gluconeogenesis.

Question 45

Consequences of 24 hours starvation include: Development of metabolic alkalosis

Answer 45

False. Free fatty acids are an important energy source and in addition, production of ketone bodies such as acetoacetic acid and B-hydroxybutyric acid increases, leading to acidosis.

Question 46

The following are examples of active transport of substances across membranes: Movement of sodium out of a nerve

Answer 46

True. Intracellular sodium concentration (15 mmol.L-1 ) is much less than extracellular (140 mmol.L-1).

Question 47

The following are examples of active transport of substances across membranes: Reabsorption of water in the proximal renal tubule

Answer 47

False. Active reabsorption of sodium and other solutes decreases the osmotic pressure of tubular fluid and passive water reabsorption occurs down the osmotic gradient.

Question 48

The following are examples of active transport of substances across membranes: Movement of water across the collecting duct

Answer 48

False. In the presence of ADH, the wall of the collecting duct (CD) becomes permeable to water, allowing water to passively follow the osmotic gradient between CD and medullary interstitium, which has very high osmolarity.

Question 49

The following are examples of active transport of substances across membranes: Iodide uptake by the thyroid gland

Answer 49

True. The process known as iodide trapping.

Question 50

The following are examples of active transport of substances across membranes: Hydrogen ion secretion by the gastric parietal cells

Answer 50

True. Via a H+/K+ ATPase (proton pump). There is a 105-106-fold hydrogen ion concentration gradient between parietal cells (pH 7.3 or so), and the gastric lumen (pH 1-2). (pH = -log10[H+]).

Question 51

Albumin: Is absorbed from the large bowel

Answer 51

False. Dietary protein is broken down into amino acids for absorption in the small intestine.

Question 52

Albumin: Is filtered at the glomeruli in significant quantities

Answer 52

False. In health, protein is not filtered at the glomerulus in significant quantities.

Question 53

Albumin: Is a specific carrier protein

Answer 53

False. Albumin is a non-specific carrier for a variety of substances such as bilirubin, fatty acids, thyroid hormone, calcium and drugs.

Question 54

Albumin: Has antibody properties

Answer 54

False. Immunoglobulins are the proteins with antibody properties.

Question 55

Albumin: Has a molecular weight of approximately 70,000 daltons

Answer 55

True.

Question 56

Closing volume: Is greater than closing capacity

Answer 56

False. Closing capacity (CC) equals residual volume plus closing volume.

Question 57

Closing volume: Is attributed to collapse of segmental bronchi in dependent parts of the lung

Answer 57

False. It is attributable to collapse of smaller airways.

Question 58

Closing volume: Tends to increase with age

Answer 58

True.

Question 59

Closing volume: Is measured by the helium dilution technique

Answer 59

False. It is measured by measuring nitrogen concentration in expired gas following a vital capacity breath of 100% oxygen. An abrupt increase in nitrogen concentration at the onset of phase 4 occurs as a result of preferential emptying of apical units and represents the volume of the lung at which dependent airways begin to close.

Question 60

Closing volume: Is reduced by moving from the supine to the upright position

Answer 60

False. However, FRC increases on moving from supine to standing and CC is then less liable to encroach on FRC.

Question 61

The oxyhemoglobin dissociation curve: May be used to calculate the P50

Answer 61

True. The partial pressure of oxygen at which haemoglobin is 50% saturated is a measure of the affinity of haemoglobin for oxygen and can be readily plotted on the curve.

Question 62

The oxyhemoglobin dissociation curve: Indicates the oxygen carrying capacity of the blood

Answer 62

False. Oxygen carrying capacity is determined primarily by haemoglobin concentration.

Question 63

The oxyhemoglobin dissociation curve: Is displaced to the left in anaemia

Answer 63

False. Red cell 2,3-DPG is increased in anaemia, shifting the curve to the right, facilitating the offloading of oxygen at cellular level.

Question 64

The oxyhemoglobin dissociation curve: Has the same shape as the carboxyhaemoglobin dissociation curve

Answer 64

False. The carboxyhaemoglobin (COHb) curve is hyperbolic rather than sigmoid shaped. In the presence of COHb, the dissociation curve of the remaining HbO, shifts to the left. In addition, haemoglobin has an affinity for CO 200 times that of O2 and COHb releases CO very slowly.

Question 65

The oxyhemoglobin dissociation curve: Is displaced to the left by passive hyperventilation

Answer 65

True. Hyperventilation causes respiratory alkalosis and shifts the curve to the right.

Question 66

Airway resistance: Can be measured using a body plethysmograph

Answer 66

True.

Question 67

Airway resistance: Is expressed as litres/kPa

Answer 67

False. Resistance = Pressure difference between alveoli and mouth per unit of airflow (compare electrical resistance: R =V/I), so the units are kPa.s.L-1

Question 68

Airway resistance: Is independent of lung volume

Answer 68

False. As lung volume is reduced, airway resistance increases markedly. At low lung volumes, small airways may close completely, especially in dependent parts of the lung.

Question 69

Airway resistance: Is increased in forced expiration

Answer 69

True. Airway compression occurs with increasing intra-thoracic pressure.

Question 70

Airway resistance: Is independent of flow

Answer 70

False. Airway resistance increases as flow changes from laminar to turbulent.

Question 71

A subject acutely exposed to an inspired oxygen concentration of 10% at sea level will: Develop respiratory alkalosis

Answer 71

True. PaCO2 decreases secondary to hyperventilation.

Question 72

A subject acutely exposed to an inspired oxygen concentration of 10% at sea level will: Secrete a more acid urine

Answer 72

False. CO2 is reduce due to hyperventilation. pH = pka + log10[HCO3-]/aPaCO2. To compensate for the respiratory alkalosis, hydrogen ion is conserved and bicarbonate is excreted in urine, decreasing plasma bicarbonate concentration to maintain the bicarbonate/CO2 concentration ratio and restore plasma pH towards normal.

Question 73

A subject acutely exposed to an inspired oxygen concentration of 10% at sea level will: Have increased pulmonary vasoconstriction

Answer 73

True. Hypoxia causes an increase in pulmonary vascular resistance (hypoxic pulmonary vasoconstriction).

Question 74

A subject acutely exposed to an inspired oxygen concentration of 10% at sea level will: Have an increased cardiac output

Answer 74

True. In an attempt to maintain oxygen delivery or flux.

Question 75

A subject acutely exposed to an inspired oxygen concentration of 10% at sea level will: Respond immediately by increasing erythropoietin production

Answer 75

False. This is a longer term response.

Question 76

Important determinants of myocardial oxygen consumption include: Heart rate

Answer 76

True. Myocardial oxygen consumption is determined primarily by heart rate, contractility and intra-myocardial tension.

Question 77

Important determinants of myocardial oxygen consumption include: Ventricular wall tension

Answer 77

True. Ventricular work correlates with oxygen consumption. Myocardial oxygen consumption is determined primarily by heart rate, contractility and intra-myocardial tension.

Question 77

Important determinants of myocardial oxygen consumption include: Myocardial contractility

Answer 77

True. Ventricular work correlates with oxygen consumption. Myocardial oxygen consumption is determined primarily by heart rate, contractility and intra-myocardial tension.

Question 78

Important determinants of myocardial oxygen consumption include: Left ventricular end-diastolic volume

Answer 78

True. This can substitute for fibre length in Starling's Law of the heart.

Question 79

Important determinants of myocardial oxygen consumption include: Pulmonary capillary wedge pressure

Answer 79

True. An increase in PCWP corresponds to an increase in preload. Ventricular work correlates with oxygen consumption. Myocardial oxygen consumption is determined primarily by heart rate, contractility and intra-myocardial tension.

Question 80

Blood vessels that contribute to physiological shunt include the: Coronary sinus

Answer 80

False. The coronary sinus drains into the right atrium.

Question 81

Blood vessels that contribute to physiological shunt include the: Thebesian veins

Answer 81

True. Some Thebesian veins drain directly into the left side of the heart.

Question 82

Blood vessels that contribute to physiological shunt include the: Anterior cardiac vein

Answer 82

False. The anterior cardiac veins drain the anterior part of the right ventricle, opening into the right atrium.

Question 83

Blood vessels that contribute to physiological shunt include the: Bronchial venous drainage

Answer 83

True. Although the bronchial veins drain into the azygous systems, the majority of bronchial venous drainage is via the pulmonary veins, thus contributing to shunt.

Question 84

Blood vessels that contribute to physiological shunt include the: Ductus venosus

Answer 84

False. The ductus venous is an embryological structure connecting the umbilical vein to the inferior vena cava, allowing about 50% of oxygenated blood to bypass the liver.

Question 85

Intracranial pressure: Is decreased by hypoxia

Answer 85

False. Hypoxia increases intracranial pressure and is a cause of secondary brain injury.

Question 86

Intracranial pressure: Can be reduced by hyperventilation

Answer 86

True. Intracranial pressure increases as PaCO2 increases.

Question 87

Intracranial pressure: Is lower when intra-thoracic pressure is low

Answer 87

True. Coughing and straining increase intracranial pressure.

Question 88

Intracranial pressure: Rises following head injury and should be treated with systemic steroids

Answer 88

False.

Question 89

Intracranial pressure: May be estimated by the Kety-Schmidt method

Answer 89

False. This technique is used to measure cerebral blood flow.

Question 90

Urinary osmolality increases in response to: Aldosterone

Answer 90

False. Aldosterone promotes both sodium and water reabsorption thereby reducing urine amount, but not the concentration.

Question 91

Urinary osmolality increases in response to: Vasopressin

Answer 91

True. ADH increases water reabsorption in collecting ducts.

Question 92

Urinary osmolality increases in response to: Cortisol

Answer 92

False. Cortisol has weak mineralocorticoid activity. Mineralocorticoid activity promotes re-absorption of both sodium and water, thereby reducing urine amount, but not the concentration.

Question 93

Urinary osmolality increases in response to: Dehydration

Answer 93

True. Dehydration increases ADH secretion from the posterior pituitary in response to increased hypothalamic osmoreceptor activity.

Question 94

Urinary osmolality increases in response to: Increased dietary protein

Answer 94

True. Urinary nitrogen excretion is increased, increasing the number of osmotically active particles.

Question 95

The tendon jerks in the lower limb are reduced if, fifty days previously, the: Lumbo-sacral anterior horn cells are damaged

Answer 95

True. This is a lower motor neurone lesion. Intact anterior horn cells are required for the efferent limb of the tendon reflex.

Question 96

The tendon jerks in the lower limb are reduced if, fifty days previously, the: Ipsilateral pyramidal tract is interrupted in the spinal cord

Answer 96

False. Corticospinal tract damage is an upper motor neurone (UMN) lesion, leading to weakness, increased muscle tone and increase in tendon reflexes.

Question 97

The tendon jerks in the lower limb are reduced if, fifty days previously, the: Contralateral internal capsule is damaged

Answer 97

False. This UMN lesion would cause an increase in tendon jerks and in muscle tone (e.g. following a stroke).

Question 98

The tendon jerks in the lower limb are reduced if, fifty days previously, the: Motor cortex is damaged on the contralateral side

Answer 98

False. This UMN lesion would cause an increase in tendon jerks and in muscle tone (e.g. following a stroke).

Question 99

The tendon jerks in the lower limb are reduced if, fifty days previously, the: Ipsilateral spinothalamic tract is interrupted by disease

Answer 99

False. These are ascending sensory fibres.