MECHANISM OF HUMAN BEHAVIOR

General Psychology

Dexter B. Cargullo

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

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.

•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 THREE COATS OF EYEBALL

- 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.

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.

THE EARS AND THE AUDITORY SENSATION

The Ears are the sense organs for hearing and the stimulus; it is made sensitive by the sound waves which is caused by the vibration of objects.

The ears consist of 3 parts:Outer EarMiddle Ear Inner Ear

PARTS OF THE EAR

OUTER EAR

Pinna – is the visible part of the ear that catches the sound and bring this sound to the auditory canal down to the middle Ear.

Auditory Canal – is a tube-like passage in the ear through which sound moves to the ear drum.

Eardrum – is a miniature (small) drum that vibrates when sound waves hit it.

PARTS OF THE EAR

MIDDLE EAR – is the small chamber which has tiny bones called malleus (hammer), incus (anvil) and stapes (stirrup)

How does it works?The malleus transfers vibration to the

anvil. The anvil transfers the vibration to the stirrup, and the stirrup brings the vibration to the oval windo.

The oval window is thin membrane between the middle ear and the inner ear.

PARTS OF THE EAR

INNER EAR – is the component of the ear that actually change the sound vibration into the form a form that can be transmitted to the brain.

HEARING DEFECTS

Conductive Deafness – is a result of disturbance in the conduction of air waves from the outer to the inner ear. Defects in oval window and basilar membrane which amplify sounds prevents the flow of vibration.

Nerve Deafness – is cause by loss of sensitivity of the receptors.

THE SENSE OF SMELL AND OLFACTORY RECEPTORS

The sense of smell or olfactory receptor is located in the upper part of the nasal cavities in a small space called olfactory region.

There are large membrane of sensitive nerve ending know as olfactory bulb. These receptors are very sensitive to gaseous elements.

CLASSIFICATION OF SMELL

Flowery scent Ethereal Smell Fruity smell Pepperminty Resinous Smoky or scorched Putrid stink

TASTE RECEPTORS AND GUSTATORY SENSATION

The receptor cell for taste are located in the TASTE BUDS which are distributed across the tongue.

There are tiny hair cell within the taste buds. These hair cells are connected to a nerve that reacts when taste stimuli cut in the taste pores. The taste is sensitive to taste. This means that solid food may be tasted only when it has become dissolved whole or partly by saliva.

4 TASTE QUALITIES

1. Sweet2. Sour3. Bitter4. Salty

Hypogeuia – loss of taste which is accompanied by the loss of smell or anosmia.

Hypogeuia and Anosmia – caused by respiratory infections within the nasal passages which has been extremely congested and obstructed.

SKIN RECEPTORS AND CUTANEOUS SENSATION

The sense organ involved in the sense of touch is the SKIN

The skin sensation respond to: touch, pressure, warmth, cold and pain.

Pain and Pressure are referred as Tactual or tactile experiences

Warmth and cold are called thermal experiences.

Sensitivity of the skin to the various stimulation is not equally distributed. Lips and fingertips are very sensitive to touch and pressure. Skin tissue is sensitive to pain when pinched or pricked. The legs is sensitive to cold.

THE CONNECTING MECHANISM

CENTRAL NERVOUS SYSTEM (CNS)

The CNS is made up of brain and spinal cord.

Brain – encased in the skull. It is responsible for the interpretation of sensory impulses, coordination and control of body activities and expression of emotions and thoughts. It is divided into 3 main parts:

Forebrain Midbrain Hindbrain

Forebrain – located at the front part of the brain. This consists of the cerebrum, cerebral cortex, thalamus and hypothalamus.

The cerebrum is the largest of the brain mass. Its principal part is the cerebral cortex which is seated of higher mental process, abstract reasoning, planning and higher mental process.

The thalamus is the receiver of information from the senses and relay this information to the cerebral cortex for processing. It is also responsible for the wakefulness and sleep.

Hypothalamus serves as the integrating center of many kind of physiological activities such as eating, sex, etc. it is also involves emotional responses and homeostasis.

Midbrain – this part serves as the connecting link between the hindbrain and the forebrain. It connects the sensory motor pathways between the lower and the upper portion of the nervous system.

Hindbrain – composed of medulla oblongata, pons and the cerebellum. The medulla oblongata is the connecting link between the spinal cord and the brain proper. It plays important functions in the essential physiological processes like respiration, heartbeat, breathing etc. The pons serves as a connection center and is involved in the motor coordination and equilibrium too. The Cerebellum function is to maintain posture and smooth out complex muscular coordination like walking, writing and even dancing.

THE SPINAL CORD

It is a large rope-like segments of nerve tissues running along the spine carrying message between the brain and the peripheral nervous systems.

In the spinal cord are spinal nerves which divide into 2 roots: dorsal and ventral.

Dorsal roots – carries sensory nerve fibers Ventral roots – carries motor nerve fiber

PERIPHERAL NERVOUS SYSTEM (PNS)

The PNS branches out from the spinal cord and the brain, and extended to the extremities of the body. It carries information in and from the CNS.

2 divisions: Somatic – control of voluntary movements of the

skeletal muscles and communication of information to and from the sense organ.

Autonomic – concerned with the parts of the body that makes it alive – heart, blood vessels, glands, lungs, etc. It has two subdivision.

AUTONOMIC SUB-DIVISIONS

Sympathetic subdivision – is the part that prepares the body to respond to stressful emergency situation. It increases heartbeat, raises BP and sends the blood to peripheral muscles.

Parasympathetic subdivision – acts to calm and relax body after the emergency situation is resolved.

Neurons – specialized cells that are the basic structural unit of the nervous system that transmit messages. Principal Parts: Cell body – found in protoplasm which is the

living part of the neuron. Dendrites – are clusters of nerve fibers which

carry messages toward the cell body. Axon – is a long, slim, tube like extension which

carries messages away from the cell body. Synapses – are point of connections between the

dendrites of some neurons and axons of others.

CLASSIFICATION OF NEURONS

Sensory Neuron – carry message from the receptors to the spinal cord and brain.

Motor Neuron- carry messages from the brain and spinal cord and send them to the motor organs like the muscles and glands.

Connector Neurons – provide connection between the sensory and motor neurons. These are found in the brain and spinal cord.

THE REACTING MECHANISM

MUSCLES AND GLAND

3 KINDS OF MUSCLES Voluntary – muscles that can be moved at the

person’s will. Also known as striped muscles, skeletal muscles.

Involuntary – muscles that cannot be moved at will. It has its own movement which are rhythmical. Also known as visceral muscle, smooth muscle. Involuntary muscles are generally found in the internal organs of the body.

Cardiac – muscles that are found in the heart.

CHARACTERISTICS OF MUSCLES

1. Contractility – ability to change from a long narrow shape while at rest and a shorter and thicker form while in action.

2. Extensibility – the capacity to be stretched or made longer.

3. Elasticity – the power of the muscle to go back to its original size and shape after contracting or stretching.

4. Tonicity – the ability to be in condition of healthy tension or partial contraction at rest.

FUNCTION OF MUSCLES

Shapes our body Secure internal organs of the body Muscles are made for motion Muscles are utilized for locomotion Muscles are used to produced heat in

the body

GLANDS

Glands are special secreting organs which pour the secretion either directly into the blood streams or pass it through the ducts or canals.

Endocrine GlandsThese secrete hormones, affect body

growth and functioning. Hormones are chemicals that circulate throughout the blood and affect the functioning and the growth of the parts of the body.(e.g. reproduction, metabolism)

Pituitary Glands The most influential gland which is found

at the base of the brain. It is called as “master gland” because of its influence on the endocrine glands. It has 2 parts:

Anterior lobe – secrete growth hormonePosterior Lobe – secrete2 important types

of hormones, the vasopresin which controls the secretion of water through the kidney, and oxytocins which stimulate the breast to produce milk.

Thyroid GlandLocated at the base of the throat. It secrets

two known hormones: thyroxine and idothyroxine.

Parathyroid GlandFound behind the thyroid glands. They

produce substance called parathormone which controls the different minerals in the blood stream specially calcium. Lack supply of this hormone will result to tetany which is the stiffening of the hand and fingers, muscles cramps and irritability.

Adrenal Gland Located on the top of each kidney. It is made up of 2

parts: adrenal cortex which secrets cortin, and adrenal medulla which secrets adrenaline hormone which serves to give extra energy needed during emergency.

Island of Langerhans IoL are small bodies floating in the pancreas. It

secretes hormone called insulin which are directly responsible in controlling sugar amount in the blood.

Gonads Gonads are sex glands. Male – Testosterone promotes

male sex secondary characteristics that make the male look kike masculine. Female – Estrogen and Progesterone