Unit 2 sensitivity and coordination

Maria boizas

Stimuli

A stimulus is anything you see,hear,touch,smell or taste.

There are two types of stimuli: Internal stimuliExternal stimuli

The smell of a flower is an external stimuli.

receptors

There are two types of receptors:Internal receptorsExternal receptors

Responses

A response is the body’s answer to a stimulus

There are two different types of responses:Muscular responses Glandular responses

Chewing is a muscular response

The senses

sight

The eye is the organ of sight.

it is made up of the eyeball and protected by the eyebrows,eyelids and eye lashes.

Process of sight

First light goes through the cornea.Then light passes through the pupil,the

opening of the iris.After that light passes through the lens

with focuses the image on the retina.The information in the retina travels to

the brain through the optic nerve

smell The nose is the organ of smell.The

receptorsof smell are in the pituitary gland,inside the nostrils.

hearing The ear is the organ os hearing. It has three parts:

The outer ear The middle ear The inner ear

The process of hearing

First the outer ear receives soundsThen the middle ear changes sounds

into vibrations.Finally the inner ear changes vibrations

into nerve impulses that go to the brain

touch The skin is the organ of touch. It is made up of three layers:

Epidermis Dermis Hypodermis

tasteThe tongue is the organ of taste.The receptors of taste are in the taste

buds.There are taste buds all around the

tongue.

The nervous system

The nervous system is made up of nerve centres and nerves.

The peripheral nervous system is made up of:Sensory nerves Motor nerves

The central nervous system has two parts:The brainThe spinal cord

neurons

They are made up of a cell body,dendrites and axons.

Neurons receive information from other neurons.

Voluntary and involuntary movements

Our bodies react to stimuli making voluntary or involuntary movements.

Voluntary movements

When we see the clouds our sensory nerves inform the brain about this.

Our brain processes the information and produces a response.

Our motor nerves transmit a response to the muscles.

Involuntary movements

The spinal cord produces a response in the case of involuntary movements.Sensory nerves transmit information about

involuntary movements to the spinal cord.The spinal cord produces a very fast

response.

The skeletal system

The skeletal and muscular system is in charge of carrying muscular responses created by the nervous system.it is made up of the skeleton and the musculature.

The skeleton

The skeleton is made up of all the bones in the body.Head bones:skull bones and facial bones.Trunk bones:spine and rib cage.Limb bones:there are two groups the upper

limb bones and the lower limb bones.

joints

The joints are located where two or more bones meet.Bones are connected by ligaments.

There are three types of joints:Moveable jointsSemi-moveable joints Fixed joints

The musculature

The musculature is the set of muscles in the body.locomotor muscles are conected to the bones.when they contract or relax,they move the bones.

Head muscles:masseter,buccinator and orbicular. Trunk muscles:sternocleidomastoid,abdominal, pectoral,intercostal and trapezius. Limb muscles:biceps,triceps,deltoid,quadriceps, gluteus and calf muscles..

The end