THE SENSE OF TASTE

The  tiny, pink bumps on your tongue are called tastebuds. They can detect special chemical in the things that you eat and drink. The chemicals mix with saliva and then the tastebuds detect them. The tastebuds produce nerve impulses and transmit them to the gustatory nerves. These nerves are inside the tongue, connected to the tastebuds. These nerves then transmit the impulses to the brain. Finally, the brain interprets the information.

THE SENSE OF SMELL

Smells are made up of gases in the air. When air goes into your nose, the gases go into your nasal passages. The olfactory cells detect the gases and send nerve impulses to the olfactory nerve. The olfactory nerve transmits the impulses to the brain and the brain interprets the information.

THE SENSE OF HEARING

Sound waves go into our ear and hit the eardrum. As a result, the eardrum vibrates.

When the eardrum vibrates, it makes the small bones inside the ear vibrate too.

The cochlea detects the vibrations and produces nerve impulses. The auditory nerve transmits these impulses to the brain. Then the brain interprets the information.

THE SENSE OF SIGHT

Light goes into the eye through the pupil. Then it passes through the lens.

The lens projects an upside down image onto the retina. This information is sent to the optic nerve.

The optic nerve transmits the information to the brain.

The cornea covers and protects the iris and the pupil.

The iris is the coloured part of the eye. It opens and closes the pupil.

The pupil is a small hole that lets light into the eye.

The lens focuses light onto the retina.

The retina detects light and colours. It sends information to the optic nerve.

The optic nerve transmits information from the retina to the brain.

THE SENSE OF TOUCH

Our sense of touch enables us to touch and feel things with our skin or dermis. Nerve endings detect information about the objects that we touch. They produce nerve impulses which the sensory nerves transmit to the brain.

NEURONS

The nervous system is made up of neurons. There are millions of neurons in your brain.

Neurons are cells that consist of a cell body, the axon and the dendrites.

To transmit messages they create electrical signals called nerve impulses.

The cell body controls the neuron and creates nerve impulses.
The axon transmits the nerve impulses to other neurons.
Dendrites receive nerve impulses from other neurons.