Human Biology and Anatomy
What you must understand
Know the major organ systems and their functions: digestion (mechanical and chemical, enzymes, absorption in small intestine, villi), circulation (heart chambers, arteries/veins/capillaries, systemic vs pulmonary circuit), respiration (alveoli, gas exchange, breathing mechanics), excretion (kidneys, nephron, urine formation), nervous system (neuron, synapse, CNS/PNS, reflex arc), endocrine system (hormones, e.g. insulin, adrenaline), immune system (non-specific and specific defence), and reproduction (gametes, menstrual cycle, fertilisation). Understand homeostasis examples (blood glucose, temperature) and blood composition (plasma, red cells, white cells, platelets).
Traps candidates fall into
- Reversing the pulmonary and systemic circuits - remember the right side of the heart pumps to the lungs, the left side to the body.
- Saying arteries always carry oxygenated blood - the pulmonary artery carries deoxygenated blood.
- Confusing absorption (small intestine into blood) with digestion (breaking food down).
- Mixing insulin (lowers blood glucose) with glucagon (raises it).
- Thinking the nervous response is slower than the endocrine - nerves act fast and briefly; hormones act slowly and longer.
Worked example / rule of thumb
Trace a drop of blood: right atrium → right ventricle → pulmonary artery → lungs → pulmonary vein → left atrium → left ventricle → aorta → body. Rule of thumb: right = lungs (pulmonary), left = body (systemic). For hormones, remember insulin lowers sugar, glucagon raises it.