Pre-clinical Sciences: Anatomy, Physiology and Biochemistry
What you must understand
Pre-clinical questions in this examination reward integrated thinking rather than isolated recall. In anatomy, know the topographic relations that explain clinical signs: the course of the facial nerve through the parotid gland, the relations of the ureter to the pelvic brim and uterine artery, the boundaries and contents of the femoral triangle, and the dermatomal and myotomal maps used to localise a disc prolapse. In physiology, master the mechanisms a question can manipulate - Starling forces across the glomerulus, the Frank–Starling curve, oxygen–haemoglobin dissociation and its shifts, countercurrent multiplication in the loop of Henle, the sliding filament model, cardiac cycle pressure–volume relationships, and the hypothalamic–pituitary axes with their feedback loops. In biochemistry, the high-yield core is glycolysis, the Krebs cycle, oxidative phosphorylation, gluconeogenesis, the pentose phosphate pathway, urea cycle, and the rate-limiting enzymes that regulate each; plus the vitamin cofactors and the classic enzyme-deficiency disorders.
Traps that appear
Questions often test the rate-limiting step rather than the pathway itself, or ask which enzyme is deficient from a clinical vignette rather than from a named disease. Distinguish afferent from efferent limbs of reflexes, and osmolarity from tonicity. In acid–base physiology, remember compensation never overshoots the primary disorder. In anatomy, a plausible distractor is usually a structure that lies near but not at the stated site.
Worked rule of thumb
For any hormone axis question, draw three boxes (hypothalamus → anterior pituitary → target gland) and mark the feedback arrow. If the target hormone is high and the tropic hormone is low, the lesion is at the target gland; if both are high, the lesion is central. Apply the same logic to thyroid, adrenal and gonadal vignettes.
Study strategy
Link each biochemical pathway to one clinical vignette and each anatomical region to one operative or injury scenario; this converts isolated facts into retrievable clusters.