Structure and function of the brain

Biology · Anatomy

Tap an area to read its job. Then switch the labels off and test yourself.

Switch the name labels off, then see if you can still name each area before you select it.

A side view of the human brain, with the front on the left. Select each of the three main areas to see where it sits and what it does.

Where the brain fits: from change to response

Step through it. Notice that the brain never touches the outside world directly. It only receives information and sends instructions.

1. 1Something changesIt all starts with a change, either inside your body (the internal environment) or around you (the external environment).+
2. 2Sensory organs detect itSensory organs all over your body pick up the change and send information about it to the brain.+
3. 3The brain processes itThe brain is the processing centre. It takes in the information and coordinates a response: it works out what the body should do.+
4. 4Impulses travel outThe brain sends its response back out through neurones, carried as electrical impulses, to parts of the body such as muscles.+
5. 5The body respondsThe muscles carry out the response, and that response affects the internal or external environment.+

Which part is in charge?

Which part of the brain controls each process?

Which of the three main areas controls this?

11 of 11 still to sort.

Pick a process, then pick the area of the brain that controls it. Then switch the rule and sort the same processes again.

Predict, then check

Two real situations. Use the map of the brain to predict what each person loses, and what they keep.

Person A has an injury to the brain stem. Person B has dementia, which affects the cerebral cortex. Which prediction fits?

What you need to know

• The brain is an organ made of billions of neurones, and it is part of the central nervous system.
• The brain processes information from sensory organs and coordinates a response, which travels along neurones as electrical impulses to parts of the body such as muscles.
• The three main areas are the cerebral cortex, the cerebellum and the brain stem (also called the medulla or medulla oblongata).
• Unconscious processes (such as heart rate, breathing rate, body temperature, sneezing and vomiting) happen all the time. Conscious processes (such as communication, learning and memory) happen only when you are awake.
• Each hemisphere controls the opposite side of the body.

The big picture

The brain is an organ of billions of neurones in the central nervous system. It processes information from sensory organs and coordinates a response, sent along neurones as electrical impulses to muscles. The cerebral cortex, the largest part, handles conscious thought; the cerebellum at the back controls balance and coordination; the small brain stem at the bottom regulates unconscious processes such as heart rate. Each hemisphere controls the opposite side of the body.

⚠ Watch out

Mixing up the cerebellum and the brain stem, because both sit low down at the back of the brain. The cerebellum controls balance and coordination. The brain stem regulates unconscious processes such as heart rate and breathing rate.

Memory hook

Top thinks, back balances, bottom breathes. The cortex on top does the thinking, the cerebellum at the back keeps you balanced, and the brain stem at the bottom keeps you breathing (and your heart beating) without you ever asking.

Check yourself

Your breathing rate keeps going while you are asleep. Name the area of the brain that controls it, say where it is found, and explain why breathing rate counts as an unconscious process.