unit two power point

THE SENSESTHE SENSES

UNIT TWOUNIT TWOSENSITIVITY AND SENSITIVITY AND COORDINATIONCOORDINATION

THE SIGHT

The organ for the sense of sight is the eye. the eye. The main part of the eye is the eyeball.

http://www.youtube.com/watch?v=gvozcv8pS3c

The sight The light reaches the eyeball.

The light goes through the cornea, the pupil and the iris.The retina focuses the image and the information goes through the optic nerve to the brain.

http://www.youtube.com/watch?v=0G0tvuc7tqo&feature=fvwrel

http://www.youtube.com/watch?v=Z8asc2SfFHM&feature=related

THE HEARING

The organ for the sense of hearing is the ear . It is made up of the outer ear, the middle ear and the inner ear.

The organ of the sense of hearing has three parts:1º The outer ear: It is made up of

the ear and outer auditory canal2º

The middle ear: it is made up of the eardrum and the small bones

3º

The inner ear: it is made up of the colchlea and the auditory nerves

TOUCHThe organ for the sense of touch is the skin. It has three layers: The epidermis, the dermis and the hypodermis.

1ºLayer

2º Layer

3º Layer

The epidermis is the outer layers and it protects our body.

The dermis is under the epidermis and it has the receptors of cold, heat and pressure.

The Hypodermis: It is under the dermis and it has fat and protects us from cold.

SMELLThe organ for the sense of smell is the nose. Receptors of smell are in the pituitary.

TASTEThe organ for the sense of taste is the tongue. Receptors for different flavours are in the taste buds.