MECHANISM OF HUMAN BEHAVIOR

General PsychologyCHAPTER 4

The Receiving Mechanism

Mechanism of receptors:

this is the different sense ( eyes, ears, nose, mouth and skin) of the body receive the stimuli from the environment.

There are three mechanisms of human behavior that help the individual to respond and interact to the environment. These are the receiving mechanisms or receptors, the connecting mechanisms or the connectors and the reacting mechanisms or reactors.

Mechanism of Human Behavior

•Interoceptors: are found in the linings of the respiratory, digestive and

genital -urinary tracts. These nerves when stimulated produce orgasmic sensation associated hunger, thirst, sex and excretion.

3 Kinds of receptors of the human body that receive the outside stimuli:

•Exteroceptors: a person becomes aware of the color, shape, smell, taste,

sound, heat, softness or roughness and cold of his envi’nt.

through the receptors w/c are located in the eyes, nose, mouth and skin. •Proprioceptors: are situated in the lining of the tendons, muscles and joints. The nerve linings w/c are connected with the nerve

pathways to the brain make the muscles feel the sensations.

The Eyes and Visual Sensation

• The Eyes:- The human eye is an organ which reacts to light from several purpose.

- The eyes give sense of vision which allows one to see the world- One has to consider the

stimulus that produces vision which is light.

- The eyes react to light which causes Visual Sensation.

- The eyes are ball-shaped so that they moved

in different directions.

- It is found within a bony cavity called Eye Socket.

- The bony cavity which contains the eyeball and its

associated  muscles, vessels, and nerves.

•The three coats of Eyeball Sclerotic coat is the tough white sheath that

forms the outer-layer of the ball. The white

 sclerotic continues around the eye; most of

which is not visible while the eyeball is

located in its socket within the face/skull.

The main area of the eye that is not covered

by the area is the front part of the eye that is

protected by the transparent cornea instead.

- Cornea is the transparent front part of the

  eye that covers the iris, pupil, and anterior

chamber.

- The cornea, with the anterior chamber and 

lens, refracts light, with the cornea accounting

for approximately two-thirds of the eye's total  

optical power.

- Choroid coat , also known as the

  choroidea or choroid coat, is the

 vascular layer of the eye, containing

 connective tissue, and lying between

the retina and the sclera .

- The front part of Choroid is Iris.

- Iris is a thin, circular structure in the eye,

responsible for controlling the diameter and

size of the pupils and thus the amount of light

reaching the retina. "Eye color" is the color of

the iris, which in humans can be green, blue,

brown, and in rarer cases, hazel , grey or

even violet.

- Pupil  is a hole located in the center of

the iris of the eye that allows light to enter

the retina. It appears black because light

rays entering the pupil are either absorbed

by the tissues inside the eye directly, or

absorbed after diffuse reflections within

the eye that mostly miss exiting the

narrow pupil.

- Once light passes through the pupil, it enters the Lens which is located behind the pupil.

- The lens act to bend rays of light to focus them on the retina.

•Retina: - Is the most innermost coat which contains the true receptor cells.

•Rods:-Are long and cylindrical.

-Are responsible for twilight vision or light of low intensity.

•Cones:-Are short, thick and tapered.

- Are responsible for daylight vision and colors.

•Fovea centralis:-Is the center of the retina which is the point of the clearest vision in the daylight.

- Is a very sensitive region of the retina.

•Optic nerve:-Is a bundle of ganglion axons at the back of the eyeball.

- It carries visual information to the brain.

•Blind spot:-As the optic nerve leaves the retina, there are neither rods nor cones.

•Optic nerve:

- The optic nerves coming from each eye splits at the optic chasm.

- Optic chasm is a point between and behind the eye wherein the more impulses from the optic nerve are reversed in the brain. • Color Vision and Night

blindness: - There are people who have limited perception of light and colors. People who find difficulty in seeing light or object at night are called night-blind because they have defective rods. Night blindness can be corrected by taking large doses of vitamin A. Vitamin A is richly found in green, leafy and yellow fruits and vegetables.

•Color blindness:There are people who cannot distinguish certain colors

either totally or partially. This condition is called color blindness. There are certain kinds of color- blindness, like the following:

- Dichromats- can match the entire colors or spectrum into two colors. There are two of this type deuteranopes

that see red as poor yellow and green as gray and

protanopes that cannot see red but black and green as

whitish gray.

- Trichomats- can see three colors from the spectrum.

•Common Eye Deviations from Normal Vision:

-Myopia or Nearsightedness:

This is cause by abnormal long eyeball so that the image is focused in front of retina. A myopic or nearsighted person cannot see objects at a far distance. They have to use eyeglasses with concave lenses.

-Hyperopia or farsightedness:

This happens when the eyeball is so short that the image is so short that the image is focused in the front of the retina. A person with this defect cannot see effectively near objects. A hyperopic person has to use eyeglass with convex lenses to correct the condition.

-Presbyopia:

This is farsightedness of old age which is caused by the slow hardening of the lens. Since the eyes cannot see near object one has to put the object little away from him in order to visualize it. A presbyopic person has to use corrective eye glasses.

-Astigmatism:

This is caused by the uneven curvature of the cornea. This generally is congenital (from birth) but it may be caused by injury of inflammation. Too much eyestrain may contribute to astigmatism

-Cross-eye:

Generally cross-eye is congenital farsightedness. Crossed-eyed person have unequal two visions in two eyes. Crossed-eyed persons have one eyed either turned outward or inward. The treatment could be done through operation.