Basic Medical Sciences
Basic Medical Sciences underpins clinical reasoning through anatomy, physiology, pathology, and pharmacology. Expect autonomic pharmacology, acid-base physiology, cell injury, inflammation, pharmacokinetics, and common drug mechanisms.
Core rules
- Anatomy is tested functionally: nerve lesions, vascular supply, and surgical relations.
- Physiology: understand compensation, not just normal values; acid-base uses Henderson-Hasselbalch and anion gap.
- Pathology: reversible versus irreversible injury, necrosis versus apoptosis, and inflammation mediators.
- Pharmacology: mechanism, absorption, distribution, metabolism, excretion, and adverse effects.
- Warfarin inhibits vitamin K-dependent clotting factors; heparin enhances antithrombin.
Worked example
A patient on warfarin has INR 6.5 and gum bleeding. The reasoning is: warfarin blocks vitamin K epoxide reductase, reducing factors II, VII, IX, and X. With bleeding, give vitamin K and prothrombin complex concentrate rather than relying on fresh frozen plasma alone when PCC is available. Review the cause and drug interactions.
Traps that cost marks
- Confusing warfarin’s vitamin K antagonism with heparin’s antithrombin effect.
- Calculating anion gap without checking albumin.
- Mixing up incidence and prevalence.
- Forgetting that aspirin irreversibly inhibits platelet cyclooxygenase.
- Ignoring renal clearance for drugs with narrow therapeutic indices.