BY:PAULA FERNÁNDEZ PRIETO

UNIT 2SENSITIVITY AND COORDINATION

STIMULIA stimulus is anything you see,touch,smell or taste

Stimuli can be: Internal stimuli External stimuli

RECEPTORS The body has different receptors to receive different types of stimulus.

Internal receptors External receptors

RESPONSE A response is the body answer

to a stimulus.

There are two different types of responses:

Muscular response Glandular response

SIGHT

The eye is the organ of sight

SIGHT (2) First light goes throught

the cornea

Then light passes throught the pupil,the opening of the iris.

After that light passes throught the lens wich focuses the image on the retina

Finally in the retina travels to the brain throught the optic nerve.

SMELL The nose is the organ of smellThe receptors of smell are in the pituitary gland,inside the nostrils

nostrils

HEARINGThe ear is the organ hearing The outer ear includes the ear

and ear canal The middle ear includes the

eardrum and the small bones The inner ear includes the

cochlea and the auditory nerve

HEARING (2) First the outer ear

receives sounds

Then the middle ear changes sounds into vibrations

Finally the inner ear changes vibrations into nerve impulses that go to the brain

TOUCH AND TASTEThe skin is the organ of touch.

It is made up of three layers.

Te tonge is the organ of taste.

The receptors of taste are in the taste buds

THE NERVOUS SYSTEMThe nervous system is made up of nerve centers and nerves.

Nerve centers intrerpret the imformation and develop response,forming the central nervous system.

PARTS OF CENTRAL NERVOUS SYSTEM

The central nervous system has two different parts:

The brain is inside the skull.it is made up of the cerebrum,the cerebrellum and the brain stem

The spinal cord is made up of many neurons and it is protect by vertebrates.

PARTS OF PARIPHERAL NERVOUS SYSTEM

The pariphetal nervous system has two different parts:

Sensory nerves Motor nerves

NEURONSBoth the central and peripheral nervous system are made up of specialised cells called neurons.

cell body axons dentrites

VOLUNTARY AND INVOLUNTARY MOVEMENTS

Our bodies react to stimuli making voluntary or involuntary movements.

Voluntary movements:the brain produces a response in the case of voluntary movements.

Involuntary movements:the spinal cord produces a response in the case of involuntary movements.

THE SKELETONThe skeleton is made up of all the bones

of the body. Head bones: skull bones and facial bones Trunk bones : spine and rib cage Limb bones: upper limb bones and lower limb

bones

THE MUSCULATURE The musculature is the set of muscles in the

body Head muscles: masseter,buccinator and orbicular Trunk muscles:

sternocleidomastoid,abdominal,pectoral,intercostal,trapezius

limb muscles:

bicep,tricep,deltoy,quadriceps,gluteus,calf muscles.