The human body, in outline
Basic Science · BECE · JSS (BECE)
Know the organ, its job, and one thing that goes wrong with it.
What you need to know
- Digestion: mouth → oesophagus → stomach → small intestine (absorption) → large intestine (water) → anus.
- Enzymes: amylase (starch), pepsin (protein, needs acid), lipase (fats).
- Blood: red cells carry oxygen (haemoglobin), white cells fight infection, platelets clot, plasma carries the rest.
- The heart is a pump with four chambers. Arteries go away from the heart; veins come back. Capillaries are the thin exchange vessels.
- Lungs: alveoli, large surface, moist, thin walls, lots of capillaries — that is how oxygen gets in.
- Reproduction: fertilisation is fusion of sperm and egg, normally in the oviduct. The foetus develops in the uterus.
The mistake to avoid
Food does not “go into the lungs.” The epiglottis closes the windpipe when you swallow. Choking is when that fails.