2. The five senes

Our five senses receive information from the world. They are important for interaction.

2.1. Sight

• Light enters our eye through the cornea and the pupil.
• The iris controls the amount of light. If there is a lot of light, it becomes small.
• The lens focuses the light.
• The image is proyected on the retina. It is connected to the optic nerve.
• The optic nerve sends the information to the brain.

2.2. Hearing

• Sound waves enter the ear through the auditory canal and the eardrum vibrates.
• The vibration moves the three small bones. They transmit this vibration to the cochlea.
• The cochlea transforms the sound into electrical signals that travel to the brain through the auditory nerve.

2.3. Smell and taste

2.3.1. Smell

• The air enters the nose through the nostrils.
• Nerve receptors send the information to the brain.

2.3.2. Taste

• When we eat, receptor on our tongue (called "buds") detect the different tastes. 
• This information is sent to the brain through different nerves.

2.4. Touch

• The dermis contains nerves that detect sensations: temperature, pain, texture, etc. This information is sent to the brain.