TOUCH

Touch is our part:

When you feel something you use the sense of touch.

From head to toe you feel the sense of touch through the entire  surface of your skin.

The skin has many layers the inner layer is called dermis, dermis has millions of nerve endings.

Touch is 4 sensations:

-HOT

-COLD

-PAIN 

-PRESSURE

Not all the body parts are equally sensitive for example, your fingertipts face and lips have more nerve endings. 

THE 5 SENSES SIGHT

  

    Your eye is like a ball. The eyes have  6 parts:

pupil, iris, cornea, lens, retina and optic nerves.

Pupil is a small black spot.

 Iris is the colorful part of an eye. Cornea is a white part of an eye.

Light passes to the cornea, arqueous humor and lens, then goes to the retina, finally the image goes to the brain and the image turns around. The pupil is like a window it  can open our shut to let the light  in.  For example if you are in a dark room your pupil is big. If you switch the light on your pupil gets small. The pupil and lens are adjusting all the time. So you can see clearly. Some people can't adjust properly and they need to use glasses.

$TASTE AND SMELL$

-We have a very good sense of taste.

- We can only detect a few basic tastes: salty, sweet, sour and bitter.

-The sense of taste is incomplete without the sense of smell.

-The nose smells the molecules in the air and sends the message to the brain.

-The animals  have a very good sense of smell.

HEARING

- Sound waves enter  the ear and they travel through the external auditory canal.

-The waves strike the eardrum, the central part of the eardrum is conected to a  small bone called  malleus, the malleus  vibrates and transmits the sounds to the other two bones:

- The incus and stapes.Stapes  moves and pushes to the oval window

-The sound passes to the cochlea wich is a structure in the shape of a snail.

- Inside of the cochlea there is the spiral organ of corti.
This organ has hair cells. Sensory nerves take the sounds vibrations and carry them to the brain.