THE SENSES

We have five senses. They are part of the vital function of sensitivity: sight, hearing, smell, taste  and touch.

1.- SIGHT

It is used to distinguish shapes, colours, size and distance.

In order to see, we need (necesitamos) light..

The light must reach your eyes. .Little light, you see things in black and white. 

Enough (suficiente) light, you see things in colour.

EYES

The eyes are the sense organs of sight.

Eyes are very delicate and need protection.

Their function is to capture light.

Parts of the eye :

a)      Outer Parts

   Eyebrow, eyelid, eyelashes, iris and pupil.

. Eyebrows protect the eyes

. Eyelids protect the eyes opening and closing them- 

. Eyelashes clean the eyes. Tears keep the eyes moist

. The iris is the coloured ring.

. The  iris control the level (nivel) of light

. The pupil is the black hole in the eye.

. The light enters through the pupil.

b)      Inner parts

There are four main parts:

The cornea,, the lens,  the retina, optical nerve.

How does light enters through the eyes?

1^st .-  light passes through the cornea. The cornea is transparent.

2^nd.-   light passes through the pupil. The pupil is the hole in the centre of the iris.

3^rd .- The lens helps the eye to focus.

4^th.-  The retina captures the light.

5^th.- The optical nerve transfer the information to the brain.

6^th.- The brain identify  us what (que) we see.

2.- HEARING

When something makes a noise, it vibrates and sends ( manda) vibrations, or sound waves, through the air.

Hearing is used to capture sounds.

Ears are the sense organs of hearing.

Some sounds are pleasant. Others are irritating.

We  have two ears, one on each side of your head.

The ears capture sound vibrations and send them to the brain.

-          Parts of the ear

The ear has three parts:  the outer ear, the middle ear and the inner ear.

The Outer ear:

 It  is external. And it is made by ( y está formado  por ) the pinna  and the ear cannal.

The pinna captures  the sound.

The sound travels through the ear canal to the middle ear.

The Middle ear:

It consists of the eardrum and three small bones.

The  sound reaches the eardrum,  and it vibrates.

The small bones make the sound louder (mas alto o comprensible).

The Inner ear

The inner ear is inside your head.

 It is very delicate.

It consists of the cochlea.

The cochlea receives the sound vibrations.

The auditory nerves send the sound vibrations to the brain

The brain interprets the received information.

3.- SMELL

The sense organ of smell is inside your nose.

One  odour  travels through the air.

It  enters the nose through the nostrils

It  reaches the nasal lining inside the nasal cavity.

The nasal cavity has special smell receptors that capture the odour..

The smell receptors send signals to the olfactory bulb in the brain.

The brain interprets the information..

4.- TASTE

Taste captures different flavours of food.

The sense organ of taste   is the tongue .

 The tongue is inside the mouth. It is covered with taste buds.

These taste buds distinguish five basic  flavours: sweet, salty, sour, bitter and umami.

The inside of the mouth and the nose are connected.

When food enters your mouth, it reaches the tongue and the nose.

Taste and smell work together to distinguish different flavours.

5.- TOUCH

It  identifies characteristics of the objects.

The skin is the sense organ of touch.

The skin has sensitive touch receptors. It allows you (te permite) to distinguish different sensations: temperature, pressure and pain (dolor).

Touch receptors send this information to the brain.

Some parts of your skin, for example your fingertips and lips, are more sensitive to touch than others.

By touching things, you can distinguish if objects are hot or cold, soft or hard, or wet or dry.