receptors

Autora: Marta García T.

SENSORY RECEPTORSThey are responsible for detecting stimuli in the world around us, and converting them into nerve impulses.

Receptors consist on special cells

which usually group to form

sense organs


RECEPTORS CLASSIFICATION

Depending on the type of stimuli required to activate them, receptors can be classified as:

Photoreceptors (light).Chemoreceptors (chemicals).Mechanoreceptors (pressure, contact on sound waves).


Pain receptors (injury).Thermoreceptors (temperature change).Propioceptors (internal receptors which receive information

about position of body parts, changes in muscle length or tension, internal processes, etc).

Can you guess any othe internal

process we must be informed

about?


FROM STIMULI TO SENSATIONS

All sense organs have common functional characteristics:

All of them are able to detect a particular stimulus.The stimulus is converted into a nerve impulse.The nerve impulse is perceived as a sensation in the CNS.


It is made up of the eyeball and some accessory organs and tissues:

Eyelids.Eyebrows.Eyelashes.Ocular muscles.Lacrimal glands.


EYE’S STRUCTURE


Sclera: outer layer of the eye. “white” of eye. it becomes transparent over iris, forming the cornea

Choroid: pigmented layer with different colour in each person. its front part is made up of muscle, forming iris. in the center of the iris there is an opening, the pupil. iris contractions dilates/constrict pupil.


Conjunctiva:Mucous membrane covering the front surface of the sclera

and lining the eyelid.

Crystalline Lens:Transparent and elastic body behind the pupil.Biconvex lens focusing light rays on the retina.Separates two chambers: anterior and posterior.


Aqueous humor: watery liquid filling the anterior cavity in front of the lens.

Vitreous humor: viscous liquid filling the posterior cavity behind the lens.


Retina: is the innermost layer, made up of two types of photoreceptor cells:

Rods: Any intensity of

light. Do not distinguish

colours.

Cones Great light intensity

( day vision). Color vision.


Visual PathwayNerve impulse leaves the eye through the optic nerve; the

point of exit has no receptors and is therefore called the blind spot.

Visual interpretation occurs in the visual cortex of the cerebrum.

http://www.youtube.com/watch?v=0HzWmldLDHI&feature=related




Read the colour of the word:


Ear functions:Hearing.Equilibrium and balance.

Structure: Outer.Middle .Inner ear.


Touch can involve perceiving different sensations:

Pressure.Pain.Temperature.Textures.


Skin receptors’ distribution is not uniform. Depending on the area, different types dominate.

What kind of sensation do they detect?


Taste allows us to detect different chemicals dissolved in saliva, resulting sensations called flavours.


Smell allows us to detect gaseous chemicals in the air.Olfatory cells are grouped together in the olfatory bulb.We can distinguish about 3.000 different smells.


• Movements are possible thanks to the relationship between:

– Bones: passive parts. Make up our skeleton (or skeletal system).

– Muscles: active parts. Make up our muscular system.

BONES• Bone cells (+mineral salts: Ca) bone tissue

bones (organs).• 2 types of bone tisssue:

– Compact– Spongy

Types of Bones

• Depending on their shape:

– Long Bones: epiphysis - diaphysis– Short Bones– Flat Bones

Cartilage• Less hard: no Calcium on it.• Ears, nose, vertebrae.• Long bones: allows growing.

JointsBones link together and form joints. There are 3 types, depending on the movement the

permit:Fixed Joints.Semi-mobile Joints.Mobile Joints.

• Mobile Joints:

– Synovial Fluid.– Ligaments.

Functions of Bones

To allow anchorage for the muscles. Support the body.Protect internal organs.Store calcium.Make blood cells in the red bone marrow of long

bones.

MUSCLESMuscular cells Muscular tissue Muscle Fibres

Muscles (organs).The ending points of the muscles, where they meet

the bones are called Tendons.

Deltoides

Esternocleidomastoideo

Triceps

Biceps

Gemelo

Cuádriceps

Abdominales

Flexores yExtensoresde los dedos

Bíceps femoral

Flexores yExtensoresde los dedos

Trapecio

Pectorales

Frontales

Orbiculares de los ojos

Orbiculares de la boca

Maseteros

Risorios

Muscular ContractionMuscles contract by getting shorter, which requires

energy.Muscles with opposite effects are called

“Antagonists”.

receptors

Documents

marta garca t

sense organs autora

receptors classification

intensity of light

pain receptors injury

crystalline lens

biconvex lens

light rays