Revise: Control and communicationStructure of the brain

Communication between cells in a multicellular organism occurs by use of nerve impulses or hormones. The central nervous system produces electrical impulses for rapid response.

Part ofBiologyRevision guides: Multicellular organisms

Structure of the brain

The human brain. The top section is labelled the cerebrum, the top end of the spinal chord enters the bottom of the brain. Next to it is the medulla and cerebellum.

The is the large folded area of the brain and is responsible for conscious thoughts, reasoning, memory and emotions.

The is found at the rear of the brain below the cerebrum and controls balance and coordinated movement.

The is found at the top of the spinal cord and contains groups of neurons that transmit electrical impulses to the heart and lungs to control heart rate, breathing rate and peristalsis.

Reflexes

A reflex action is a rapid automatic response to a stimulus (anything an organism can detect). Reflex actions are involuntary and do not necessarily involve the brain.

Reflex actions protect the body from further damage by allowing it to react quickly to stimuli, such as high temperatures, that may be harmful.

Reflex actions are quick because there is a direct link in the spinal cord called an inter neuron (between the sensory neuron and a motor neuron) that causes a muscle to make the protective response.

The circuit of the neurons that act to produce the reflex action is called the .