Clinical measurement SAQs

BP measurement - Oscillometric non-invasive monitor

see 20050606(01)

• Briefly describe the principles and sources of error in the measurement of systemic arterial blood pressure using an automated oscillometric non-invasive monitor. (03A13)
• Briefly describe the principles and sources of error in the measurement of arterial blood pressure using an automated oscillometric non-invasive monitor. (00B2)
• Briefly describe the measurement of blood pressure using an automated oscillometric non-invasive blood pressure monitor. Briefly outline the problems of this kind of monitor. (1996)
• Write short notes on the principles of oscillometry. (1992)
• Write short notes on the ideal properties of a pressure transducer. (1991)

pH measurement

• Briefly describe the measurement of pH in a blood sample using a pH electrode. (01A3)
• How does a fall in temperature influence blood gas solubility and acid base values? (99B1) (98A6)
• Write short notes on measurement of acid base disturbances. (1991)

Cardiac output measurement

• Explain how cardiac output is measured using a thermodilution technique. (00A1)

Oxygen measurement

See 200500606(02)-(03)

• Describe how the partial pressure of oxygen in a blood sample is measured using a Clark electrode. (99B7)

 

• Briefly discuss the factors which influence the measurement of oxygen saturation using a pulse oximeter. (1993)

Carbon dioxide measurement

• Explain briefly the causes of differences between measured end tidal and arterial partial pressures of carbon dioxide. (1996)
• Write short notes on principles of measurement of end tidal carbon dioxide tension. (1992) (1990)

Humidity measurement

 

• Compare 2 methods of measuring humidity. (1994)

Heat vs Temperature

• Differentiate between the terms 'heat' and 'temperature'. Explain briefly the principles of a mercury thermometer, indicating its advantages and disadvantages. (99A5)
• Briefly differentiate between the terms 'heat' and 'temperature'. Explain briefly the principles of a thermistor indicating its advantages and disadvantages. (95B7)

Gas flow

• Briefly describe the differences between laminar and turbulent flow. List the factors that increase the probability of turbulent flow. (97B6)

Ultrasound

• Explain the physical principles of ultrasound imaging. (02B14) (98B4)
• Briefly explain the principles of Doppler ultrasound used to measure cardiac output using echocardiography. (98A4)

Pneumotachograph

• Outline the principles of a pneumotachograph. What factors affect the accuracy of this device? (02A7)
• Outline the principles of the pneumotachograph. What factors affect the accuracy of this device? (95A5)

Others

• Write short notes on exponential functions. (1991)

Respiratory

Control of Respiration

1. List physiological factors which increase respiratory rate. Include a brief explanation of the mechanism by which each achieves this increase (02B10)(1995)
2. Write brief notes on breathlessness in exercise (1993)

Mechanics of breathing

1. Describe the factors that affect lung compliance. (03A14, 1990)
2. Describe the determinants of work of breathing in an adult human at rest. Explain how to minimise work of breathing. (01B2, 00A5, 1991)
3. ???? Short notes on measurement of transpulmonary pressure. (1991)

Ventilation-perfusion inequalities

1. Describe the gravity dependent processes which affect pulmonary blood flow. What changes take place when the pressure increases in the pulmonary vessels? (97A2)
2. Compare the effect on arterial blood CO2 and O2 levels of ventilation/perfusion inequalities (1997)
3. Define 'Venous Admixture'. Briefly explain how venous admixture influences arterial O2 tension and how an increase in inspired O2 concentration may affect this. (02A3) (95B1)

Gas Transport in the blood

1. What is 2,3, DPG? How is it produced in the red blood cell and how does it interact with haemoglobin? What is its relevance in altitude exposure, stored blood and anaemia. (95A1) (1991)
2. Explain how oxygen supply of organs is maintained during isovolaemic haemodilution (02A1)
3. Describe the ways in which CO2 is carried in the blood (99B5)
   Describe the role of haemoglobin in the carriage of carbon dioxide in the blood (97A3)
4. Explain the difference between perfusion limitation and diffusion limitation in the transfer of gas between alveolus and pulmonary capillary. Outline the factors that determine whether gas transfer is perfusion or diffusion limited. (03B12)
   Describe the factors that affect the transport of oxygen and carbon dioxide from the alveolus to the blood. (99A3)
5. List the normal values for mixed venous blood gases and briefly explain the factors determining mixed venous oxygen tension.(1996)
   Briefly describe the factors that influence the partial pressure of oxygen in mixed venous blood (00A2)
   What factors influence the mixed venous CO2 tension. Briefly explain how these factors exert their influence. (1993)
6. Briefly explain how an oxygen debt arises and how the body deals with it (96B8)

Pulmonary gas volumes and ventilation

1. Describe the factors that affect airways resistance. (99B3, 03B13)
2. A. Draw an expiratory flow volume curve for a forced expiration from total lung capacity. Describe its characteristics in people with normal lungs, as well as those with obstructive and restrictive lung disease (00B3)
   B. Draw a respiratory flow/volume loop and outline how it is obtained. Briefly explain the physiological mechanisms involved in the concept of flow limitation. (96B6)
   C. Draw a flow/volume curve for a maximum forced expiration in a person with healthy lungs from: (a) Total lung capacity; (b) Function Residual capacity. Explain your curves. (98A2)
3. Briefly describe the potential causes of a difference between measured end-tidal and arterial partial pressure of carbon dioxide (03B11) (96B7)
   What is the end tidal CO2? How does it differ from arterial CO2 tension and the mixed expired CO2 tension? What factors influence its value? (1995)
4. Write short notes on physiological dead space (1990)
5. Explain the factors influencing the distribution of ventilation during the inhalation of 500ml of air from Functional Residual Capacity in the erect posture (97B7)

Pulmonary circulation

1. What is a normal value for pulmonary vascular resistance? Outline physiological factors that influence pulmonary vascular resistance. (00A3)(02A4)
2. Briefly outline the differences between the pulmonary and systemic circulation (1995)

Applied respiratory physiology

1. What are the physiological consequences of decreasing functional residual capacity by one litre in an adult? (01A8)
2. Explain the effects of intermittent positive pressure ventilation on left ventricular output. (98A1)(01B1)(96B3)
3. Explain briefly how oxygenation of organs can be maintained during isovolaemic haemodilution. (96B5)

Cardiovascular physiology

 

28 Questions

 

Electrical Properties of the Heart

1. Draw a labelled diagram of a cardiac action potential highlighting the sequence of changes in ionic conductances. Explain the terms 'threshold', 'excitability', and 'irritability' with the aid of a diagram. (02A2) (1995)
2. Briefly discuss the interaction of the action potential duration and conduction velocity in the ventricular myocardium and its effect on myocardial performance. (1993)

Determinants and Control of the Cardiac Output

1. Draw a pressure volume loop for a left ventricle in a healthy adult and state the normal pressures and volumes. Outline the information which can be obtained from a pressure volume loop and how such a loop can be constructed. (02B9)(1996)
2. Draw and label a left atrial pressure trace against time. List the physiological factors which effect left atrial pressure and explain their effects. (95A3)
3. Quote Starlings law of the heart. Outline the factors that determine the right ventricular end diastolic volume. (1993)
4. Discuss the relationship between cardiac output and venous return. Include factors that determine the magnitude of both. (1990)

Peripheral Vascular System

1. Explain the physiological processes involved in the development of interstitial oedema. (01B8)
2. Describe the substances released by the endothelium. Explain the role they play in regulating blood flow through the peripheral circulation. (01A6)
3. Draw both aortic root and a radial artery pressure wave forms on the same axes. Explain the differences between them. (99B8)
4. Explain the significance of plasma oncotic pressure in capillary fluid dynamics. (99A8)
5. Explain the local effects of a decrease on plasma colloid osmotic pressure in the skeletal muscle capillary bed. (97B1)
6. Briefly discuss the factors that influence the rate of blood flow through a capillary bed. (1994)
7. Describe the relationship between vascular tone and tissue oxygenation. (1994)
8. Briefly discuss the humoral factors that control blood pressure. (1993)
9. Give an account of the Starling forces within the capillary circulation. Include specific reference to the pulmonary and glomerular capillaries. (1991)

Control of Circulation

1. Describe the role of baroreceptors in the control of systemic arterial pressure. (03B10) (00B1)
2. Describe the autonomic innervation of the heart and the direct effect of autonomic stimulation on the heart. (99A7)
3. Describe the compensatory mechanism in a fit person moving from the supine to the erect position. (98B2)
4. On arising from the horizontal position, in a normal gravitational field, a series of reflex adjustments follows which results in a redistribution of blood volume and body water. DISCUSS the physics and physiology involved. (94B1)
5. Explain the cardiovascular responses to a Valsalva manoeuvre maintained for 30 seconds. What can be learnt about cardiovascular function from observing these responses? (94B2)
6. Briefly discuss the humoral factors that control blood pressure. (1993)
7. Write short notes on volume receptors. (1992)

Regional Circulation

1. Describe the effects of tachycardia on myocardial oxygen supply and demand in a normal heart. (03B9)
2. Explain the mechanisms that maintain cerebral blood flow on moving from a supine to a standing position. (03A12) (99B6) (96B4)
3. Describe the factors influencing hepatic blood flow. (03A10) (99A6)
4. Outline the factors that determine coronary vascular resistance. (02B11)
5. List the determinants of coronary artery blood flow. Briefly compare phasic coronary blood flow in the left and right coronary arteries. (1997)
6. The heart rate of a healthy 20 yr old goes from 55bpm to 130 bpm after receiving atropine IV. Describe the effects of tachycardia on myocardial O2 supply and demand in a normal heart. (95A4)

 

Renal Physiology

 

Questions

 

1. Outline the role of the kidney in the regulation of body water. (03B14)
2. Describe the functions of the loop of Henle, including the physiological mechanisms involved. (03A16)
3. Explain the physiological processes which cause oliguria in response to hypovolaemic shock. (95B,02A6)
4. Explain how the kidney handles glucose. Describe the physiological consequences of glycosuria. (01B6) (99B4)
5. Describe the factors governing glomerular filtration rate. (00B8) (98A5)
6. List the hormones that regulate renal tubular reabsorption and describe their action and site of action. (00A7)
7. Outline the role of the kidneys in the regulation of total body water. (99B4) (95A9)
8. Describe the concept of renal clearance and its use to estimate glomerular filtration rate. (98B1)
9. Describe the process of tubuloglomerular feedback. (98B3)
10. Explain the physiological processes which cause oliguria in response to hypovolaemic shock. (95B2)
11. Explain the mechanisms involved in sodium handling by the kidney. (94A3)
12. Describe how the body detects and responds to water deficit (01A, 05A)

 

Acid and base physiology

4 Questions

 

1. Explain the role of haemoglobin as a buffer. (03A9) (1992)
2. Explain how metabolic acidosis develops in hypovolaemic shock. Describe the consequences of metabolic acidosis to the body. (98B5)
3. Describe the effects of intravenously administered sodium bicarbonate (8.4%) 100ml used in asystolic cardiac arrest in a 70 kg man (95A6)
4. Write short notes on extracellular buffers. (1990)

Fluid & electrolyte physiology

 

10 Questions

 

1. Describe how the body detects and responds to a water deficit. (01A7)
2. Outline the determinants and regulation of extracellular fluid volume. (01A1)
3. In the diagram below indicate how the solvent and solute move a cross a semipermeable membrane and give a brief explanation of the principles involved. (96A7)
4. Outline the effects of IV administration of 500 mls of 20% mannitol, and the potential problems associated with its use. (95B5)
5. Explain how a metabolic alkalosis develops in an adult patient with a small bowel obstruction and nasogastric losses in excess of 1000ml per day for 5 days. Give a brief account of the physiological principles determining fluid replacement. (1995)
6. Outline the effects of a rapid injection of 100mls of hypertonic Iodine containing angiography contrast medium in an otherwise healthy adult. (1994)
7. Compare the advantages and disadvantages of synthetic colloids and SPPS in volume replacement. (1994)
8. Write short notes on serum calcium. (1992)
9. Write short notes on osmoreceptors. (1992)
10. Write short notes on the regulation of calcium. (1990)

Thermoregulation

6 Questions

 

1. Define the "thermoneutral zone". Briefly explain how the body regulates temperature when the ambient temperature exceeds thermoneutral zone. (03A11) (1996)
2. Explain briefly the role of the skin in maintaining a normal body temperature. (01A5)
3. Briefly describe the influence of general anaesthesia on intraoperative temperature regulation. (97B4)
4. Explain the role of the skin in maintaining a normal body temperature. (96B2)
5. Discuss temperature regulation in the human, explaining the physics of heat transfer and how physiological control mechanisms reflexly use these to maintain constant core temperature as external temperature changes and insulation is altered. Explain the concept of thermoneutral zone and how this varies with body size. (94A1)
6. Give a brief account of the physiological consequences of hypothermia. (93A3)

 

Physiology of Blood & Immune System

 

8 Questions

 

1. Briefly explain the changes that occur in stored whole blood. (02B12) (95B10)
2. Explain the main difference between the intrinsic and extrinsic pathways of coagulation. (01B7)
3. Outline the principles of compatibility testing of allogeneic (homologous) blood for transfusion. (00B4)
4. Briefly describe the breakdown of haemoglobin after red cell lysis. (00A8)
5. Explain the mechanisms that prevent blood clotting in intact blood vessels (do not draw the clotting cascade). (99A2) (95A7)
6. Briefly discuss the physiological roles of plasma proteins. (98B6) (1990)
7. Briefly describe the complement system. (97B5)
8. Briefly outline the role of platelets in haemostasis. (97A6)

Neurophysiology

 

13 Questions

 

1. Briefly describe the NMDA (N-methyl d-aspartate) receptor and its physiological role in the central nervous system. (03B15) (98A8)
2. Briefly discuss the physiological control of intraocular pressure. (00B6)
3. List the physiological factors which determine intracranial pressure and explain briefly how it is regulated. (97B3) (1996) (95B6)
4. What is saltatory conduction and what are the advantages of this type of conduction? (97A5)
5. Explain briefly the physiological mechanisms whereby an action potential arriving at a synapse might not be conducted. (96B1)
6. Outline the factors contributing to the generation and maintenance of the resting membrane potential. (1996)
7. Draw a graph of a nerve action potential and outline its physiological basis. (1994)
8. Briefly outline the physiological factors that determine cerebrospinal fluid (CSF) formation. (1994)
9. Discuss the physiological consequences which you would expect to occur during the first few hours of a traumatic section of the spinal cord at the level of C6 assuming no other injuries. (93A1)
10. Outline the neuroendocrine functions of the brain. (1993)
11. Write short notes on the axonal membrane. (1991)
12. Write short notes on cerebrospinal fluid. (1991)
13. Write short notes on synaptic transmission. (1990)

 

Maternal, foetal, neonatal physiology

 

Questions

 

1. Explain the Bohr and Haldale effects in trans-placental gas exchange. (02B16)
2. Describe the physiological changes that occur in respiratory function during pregnancy. (01B4)
3. Indicate the sequence of the physiological changes to the fetal circulation at birth and briefly describe the mechanisms which account for these changes. (01A4)
4. Explain the Bohr and Haldane Effects in trans-placental gas exchange. (99A1)
5. Indicate the sequence of the physiological changes to the fetal circulation at birth and briefly describe the mechanisms that account for these changes. (97B8)
6. Describe the physiological changes that occur in respiratory function during pregnancy and what significance these changes have to anaesthesia. (95A8)
7. Write short notes on placental oxygen transfer. (1990)

 

Cellular physiology

 

7 Questions

 

1. Outline the factors contributing to the generation and maintenance of the resting membrane potential. (02A5)
2. Describe the structure and function of voltage gated ion channels. (01B5) (97A1)
3. Briefly describe structure of mitochondria. Outline the metabolic processes that occur in mitochondria. (98B7)
4. Describe mechanism of action in G proteins. (97B2)
5. Briefly describe role of intercellular tight junctions. (93B3)
6. What are 'membrane channels'? How are they investigated? Describe one commonly interfered with in Anaesthesia (93A2)
7. Write short notes on the Endoplasmic Reticulum. (1991)

 

Endocrine and metabolic physiology

 

11 Question

 

1. Describe the physiological actions of thyroid hormones. (03A15)
2. Briefly describe the functions of renin and angiotensin. (02B13)
3. Describe the fuel sources used during early and sustained fasting in man. (01B3)
4. Outline the actions of insulin that affect fat metabolism. (00B7) (98A7)
5. Compare the effects of a six hour fast from fluids and food with those of a 24 hour fast in a healthy adult. (1996)
6. Outline the physiological consequences of  hyperosmolar diabetic ketoacidosis. (95B8)
7. Outline the physiological effects of bilateral adrenalectomy. (1994)
8. Discuss the physiological consequences of preoperative fasting (food and water) for 12 hours in a healthy young adult. Include in the discussion the effects on the body of this food and water deprivation and the physiological mechanisms that compensate for them. (93A1)
9. Discuss the role of the hypothalamus in physiological control mechanisms. (1992)
10. Write short notes on the thyroid hormones. (1992)
11. Write short notes on control of blood glucose concentration. (1990)

 

Gastrointestinal physiology

 

11 Questions

 

1. Outline the mechanism of secretion of hydrochloric acid by the stomach. Briefly describe how secretion of hydrochloric acid by the stomach is controlled. (03B16)
2. Give a brief account of the mechanisms which regulate gastric secretion. (02B15)
3. Describe the physiological factors that contribute to the competence and tone of the lower oesophageal sphincter. (02A8)
4. Write short notes on the cardiac (lower oesophageal) sphincter. (1990)
5. Describe the control of gastric emptying. (00A6)
6. What physiological factors contribute to the competence and tone of the lower oesophageal sphincter. (99B2)
7. What factors oppose gastro oesophageal reflux? (97A4)
8. Outline the factors determining the rate of flow of bile into the duodenum. (1994)
9. Write short notes on bilirubin. (1991)
10. Describe the mechanism of swallowing. (1993)
11. Write short notes on the biochemical changes associated with pyloric stenosis. (1991)

 

Muscle physiology

 

6 Questions

 

1. Briefly describe the effect of resting muscle length and load conditions on the tension generated by a skeletal muscle. How do these factors affect the velocity of shortening? (01A2)
2. Briefly discuss the relationship between structure and function in skeletal muscle. (00B5)
3. Briefly describe the difference between a single twitch and a tetanic contraction in a skeletal muscle fibre. Include in your answer the physiological basis for the development of a tetanic contraction. (00A4)
4. Briefly describe the structure of a mammalian skeletal muscle fibre and explain how its structure is related to its contractile function. DO NOT describe excitation-contraction coupling. (98A3)
5. Briefly discuss the role of calcium in the coupling of electrical and mechanical events in skeletal muscle. (1993)
6. Write short notes on isometric and isotonic muscle contraction. (1990)