Reference articles on history, science, culture and more
Learning path · Beginner

Inside the human body

Cells, genes, the heart, the brain and the immune system, in the order that makes each one easier. 7 guides, about 55 minutes of reading.

  1. The cell: the unit everything living is built from

    What is inside a cell, what each part does, and the difference between the two great classes of cell.

    Step 1 · Biology · 8 min read
  2. DNA, RNA and how a gene becomes a protein

    The structure of the molecule, the code it carries, and the two steps that turn instructions into working machinery.

    Step 2 · Biology · 8 min read
  3. Genetics and inheritance

    From Mendel's peas to the human genome: how traits pass from parents to children and why siblings differ.

    Step 3 · Biology · 8 min read
  4. Human body systems, and how they cooperate

    A tour of the major systems, what each one solves, and the principle that links all of them.

    Step 4 · Biology · 9 min read
  5. The heart and circulation

    How a fist-sized muscle pumps blood through about 100,000 kilometres of vessels, and what keeps it healthy.

    Step 5 · Health · 7 min read
  6. The brain

    The structure of the brain, how neurons communicate, and what we know about how it changes over a lifetime.

    Step 6 · Health · 8 min read
  7. The immune system

    How the body recognises invaders, fights them off and remembers them, from skin and fever to antibodies and T cells.

    Step 7 · Health · 8 min read