Follow the body from a single cell up to the organ systems that feed it, move it, control it and defend it — each one in an order that builds.
Every system in the body is made of cells, so that is where this starts — what they are, how they multiply, and how they group into systems.
Food in, oxygen in, energy out. These five trace a meal and a breath all the way to the cells that use them.
The macronutrients and micronutrients the body needs, the main food groups, and what a balanced diet looks like.
The organs of digestion, enzymes, and how nutrients are absorbed.
Breathing mechanics, the alveoli, gas exchange, and lung disease.
The heart, blood vessels, blood components, and double circulation.
Aerobic and anaerobic respiration, ATP, and the differences between them.
How the body holds itself up, moves on purpose, and coordinates the whole operation through nerves and hormones.
What attacks the body, how it fights back, and how the instructions get passed on.
Bacteria, viruses, fungi, and protists — structure, role, and disease.
Pathogens, physical barriers, white blood cells, antibodies, and vaccination.
Sexual and asexual reproduction, fertilisation, and the male and female reproductive systems.
How genetic information is stored in DNA and passed from parents to offspring through chromosomes, genes, and the rules of inheritance.