2014 First Sitting

2014A 01: 26% of candidates passed this question. It was expected that candidates would outline both motor and sensory pathways and mention a reflex arc and conscious pathways.

2014A 02: 61% of candidates passed this question. Most candidates managed to provide a classification of calcium anatagonists. The pharmacology of verapamil was less well understood. The structure for answering a pharmacology question was often poor and there was commonly a lack of precision in pharmacokinetics. We suggest that candidates look at a general pharmacokinetic structure when answering these questions. One approach would be a structure that covers drug name and description, pharmaceutics (chemistry/ ampoule contents), Pharmacokinetics, Pharmacodynamics (Think CNS/CVS/Resp/GIT etc. if relevant), Dose and Side effects then Indications and Contraindications can help organize the information.

2014A 03: 58% of candidates passed this question. Candidates who failed the question did not answer the actual question. They did not discuss the neural integration but instead listed various inputs into the CTZ and vomiting centre. It was expected candidates could detail the pathways involved (afferent and efferent limbs) and describe the relationship with the coordinating centres. For example, afferent pathways to the vomiting centre include stretch and chemoreceptors located throughout the GIT via vagal and sympathetic nerves, pharyngeal touch receptors via glossopharyngeal nerves etc. Again structuring pharmacology answers was often poor.

2014A 04: 26% of candidates passed this question. This question was variably answered, with a wide range of marks. Candidates often mentioned central regulation, anatomy, respiratory mechanics, static lung volumes or gas transfer, but did not provide comprehensive cover of all areas. Very few clearly described the extent of any change (either as a percentage or actual amount relative to the non-pregnant state). A number of candidates presented information well in diagrammatic form (e.g. static lung volumes) however then repeated this same information in text, which was unnecessary.

2014A 05: 63% of candidates passed this question. This question was generally well answered with narrow variance; very few candidates discussed factors predisposing to hepato-toxicity or renal toxicity. Discussion of pharmacokinetics only gained marks when relevant to toxicity.

2014A 07: 34% of candidates passed this question. Explanation of several crucial principles was expected for a good answer. These would include that Haemoglobin can be measured and quantified with a light absorbance technique; based on the Beer Lambert law (a description of this was required). In addition, oxygenated haemoglobin must be distinguished from reduced haemoglobin (the 2 dominant species of Hb) and that the oximeter determines pulsatile from non pulsatile blood. The oximeter accounts for ambient light and that “R”, a ratio of absorbances during pulsatile and non pulsatile flow is calculated and compared within a computer algorithm to standardised values of SaO2 to deliver a final value. Mention of limitations was not required except to answer the second part of question. Common omissions included failure to describe accurately the Beer Lambert Law, and no explanation of how pulsatile component was detected, or ambient light accounted for. Many candidates understood the clinical inaccuracy associated with CO and Met HB, but failed to identify the spectrophotometric reason and application of the R value for this discrepancy.

2014A 08: 34% of candidates passed this question. This question required a description of excitation- contraction coupling. Marks were gained for a brief outline of the structure of a sarcomere and how it facilitates shortening. An explanation of membrane processes, receptor interactions and the contraction processes was required. Mention of the role of ATP was also required and marks were gained for commenting on the mechanism of return to the relaxed state. Most candidates wrote extensively on the nerve action potential and neuromuscular junction transmission, with minimal reference to events occurring within the skeletal muscle cell membrane. They could not gain marks for this. Few candidates demonstrated knowledge of the ATP dependent walk along processes of myosin heads during contraction.

2014A 09: 16% of candidates passed this question. Speed of onset is related to how quickly an effective dose reaches the neuromuscular junction, the type of interaction with the receptor and the margin of safety of the receptors. Examples of parameters that increase speed of onset include a high drug rate of delivery (high CO, high muscle group blood flow, and fast injection rate), high drug concentration (higher dose, low potency, higher ED 95, lower protein binding) or a depolarising block. A good answer would include a list of these factors, with a brief explanation. Mention of other factors such as electrolyte disturbances gained additional marks. It was expected that the direction of an effect would be clearly indicated (e.g. “potency” would not score a mark unless the candidate wrote – “low potency increases speed of onset”, etc.). These drugs are charged molecules which do not cross cell membranes and have a low volume of distribution. Absorption from GIT, Lipid solubility, pKa, metabolism and clearance have minimal relevance to speed of onset.

2014A 10: 63% of candidates passed this question. Generally candidates provided an accurate classification of bacteria based upon Gram staining and shape. None or poorly staining organisms were often overlooked. Mechanism of resistance was also well covered, with examples. Areas of weakness were a lack of descriptive detail and/or omission of an example for each mechanism. Mechanisms such as metabolic blockade of essential pathways for antibacterial action and active removal of intracellular antibiotic were more commonly omitted.

2014A 11: 19% of candidates passed this question. Candidates generally provided detailed description of the cell lineage that led up to the production of the mature red blood cell (RBC), but often omitted to mention those aspects unique to the RBC that were essential to its functions (e.g. biconcave shape gives the RBC a greater surface area and shorter distance to central regions, thus optimising diffusion of gases; the RBC enhanced ability to change shape and travel through narrow capillaries; lack of organelles maximises space for Hb, etc.). Mention of RBC function often lacked detail (e.g. restricted to just mentioning “O2 carriage”) or failed to mention, and describe, the RBC’s role in acid base buffering and HCO3- production.

2014A 12: 8% of candidates passed this question. Most candidates failed to fully comprehend the question. Candidates displayed some difficulty in differentiating regulation at a local level (which is what the question asked for) from that of central regulation (e.g. sympathetic nervous system activity, cardiac output, etc.), which was not what the question asked for. Other omissions were a failure to define and explain autoregulation. Most candidates mentioned the myogenic and the metabolic theories, but failed to provide sufficient details as to their mechanisms. It was expected candidates would provide some detail as to locally acting factors. Adenosine and nitric oxide were mentioned on occasions but others such as endothelin and prostacyclin were often omitted.

2014A 13: 26% of candidates passed this question. Many candidates struggled with this question. A good answer included a brief description of the role of the cough reflex, an outline of the sensory pathways, central integration and motor pathways of the reflex, and a description of the components of the cough reflex. Most candidates failed to accurately describe the sequence of events involved in the cough reflex. Very few gave sufficient detail on the nerve supply of the larynx

2014A 14: 74% of candidates passed this question. This question was well answered. It is a structured question that guides candidates through exactly what is required. Well drawn graphs were a particularly effective means of scoring marks.

2014A 15: 34% of candidates passed this question. There was a good understanding of the definitions of compliance but many candidates failed to clearly demonstrate an understanding of the difference between static and dynamic compliance. Many candidates had little knowledge of how compliance is measured. It was expected that descriptions of methods to measure static and dynamic compliance would be provided. There were frequent errors in descriptions that were provided

2014A 16: 60% of candidates passed this question. The structure of the cell membrane was generally well covered by most candidates. Many had difficulties structuring an answer for the transmembrane transport processes. Dividing this section into proteins (some receptors, channels etc.) and carbohydrates (some receptors, immune reactions etc) followed by a very brief discussion of each type of process would have aided candidates towards providing a good answer.

2014A 17: 71% of candidates passed this question. The first part of this question was answered well by most candidates. Generally, the second part of the question was poorly organised by many candidates, the consequence being that many opportunities for picking up marks were lost. A brief statement as to what lignocaine is, its presentations and dose, some facts about PD and PK followed by a few lines on toxicity (CC/CNS ratio) was mostly what was required. Only a few candidates mentioned lignocaine toxicity

2014A 18: 40% of candidates passed this question. An overview of the Internal Jugular vein stating where it is formed and terminates would be a good start. The important surface anatomy of the vein (left and right) followed by mention of the important anatomical relationships was then required. Few candidates mentioned anatomical variations. Many answers had no identifiable structure and went back and forth around the topic as information came to mind. A number of answers contained very rough diagrams that did not contain mark worthy information but took time to draw. The second part of the question was generally well answered by those attempting it. Many candidates ignored or forgot about this part of the question. Some candidates wrote 2 or more pages of significant detail in stark contrast to what they had written for the first part of the question. The percentage of marks allocated is a good guide as to the level of detail required in the answer.

2014A 19: 58% of candidates passed this question. This is a core question. It was expected candidates could provide a definition (heart rate x stroke volume) and then move on to outline factors that affect it (afterload, preload, contractility). Additional marks were awarded for descriptions of the relationship to mean systemic filling pressure and other influences beyond this. Most candidates described a thermodilution cardiac output curve but almost all described the technique as based on the “Fick equation or method” (which is used to estimate cardiac output from oxygen consumption). Very few candidates correctly identified the Stewart Hamilton equation as the integration method used to relate cardiac output (flow) to temperature change as an example of indicator dye dilution. Candidates seemed to lack depth and understanding on this topic.

45% of candidates passed this question. This is a very broad and open question. While a structured approach was useful, a sound knowledge of first principles or even being able to “think on the fly” would have provided candidates with enough opportunities to generate a pass.

2014A: 37% of candidates passed this question. Candidates who described an overall view of the body’s buffer systems scored well. Most candidates could define buffer and could discuss the bicarbonate buffer system; however this was not sufficient to pass the question. To pass there had to also be a discussion of the other buffer systems including phosphate, protein (haemoglobin, plasma proteins and intracellular proteins), ammonia and bone. Best answers included discussion of open versus closed systems and the relative contribution of the differing buffer systems in blood, intracellular fluid, extracellular fluid and urine.

2014A 23: 40% of candidates passed this question. Generally this question was well answered. Almost all answers gave the correct value for GFR and the correct formula for Starling’s forces across the glomerular membrane. Better answers discussed the physiological factors affecting each force (hydrostatic and osmotic) across the membrane in a stepwise logical manner. Some answers discussed the control of renal blood flow; this was not expected and therefore was not rewarded

2014A 24: 11% of candidates passed this question. This question was poorly answered with a low pass rate; which was unexpected for this core topic. In general, completed answers demonstrated good understanding of the analgesic mechanisms of opiates, but only superficial understanding of respiratory depression and constipation. Better answers explained the decreased responsiveness of the respiratory centre to CO2, and the effects of opiates on the enteric nervous system and peristalsis. VIVAs A. Pharmaceutics B. Pharmacokinetics C. Pharmacodynamics D. Variability in Drug Response E. Cellular Physiology F. Respiratory oxygen, measurement of oxygen and principles around humidity Resp physio, effects of obesity G. CVS Cardiovascular physiology, Venous return, cardiac function curves, ICC anatomy H. Renal renal physiology and diuretic pharmacology I. Body Fluids and Electrolytes J. Acid Base K. Neuro Propofol,pharm, basic kinetics for bolus and infusions, side effects L. Musculoskeletal M. ANS N. Liver Hepatic physiology, Cerebral physiology O. GIT glucose and lipid metabolism, daily nutritional requirement, insulin physio P. Nutrition and Metabolism Q. Haematology R. Thermoregulation measurement of temperature, physical principles of flow, ionic changes across membranes S. Immunology T. Microbiology U. Endocrine V. Obstetrics W. Measurement and Monitoring X. Procedures