CHAPTER 3

THE PHYSIOLOGICAL FOUNDATION

OF BEHAVIOR

HUMAN BEHAVIOR IS INFLUENCED BY MANY FACTOR

THESE MULTIPLE BASES OF BEHAVIOR, PHYSIOLOGICAL AND PSYCHOLOGICAL, ARE APPARENT IN ALMOST ALL AREAS OF HUMAN FUNCTIONING

UNDERSTANDING MANY BASIC PHYSIOLOGICAL FACTS AND THEORIES, FROM HOW WE SEE AND HEAR TO ALTERED STATES OF CONSCIOUSNESS, DEMANDS BASIC UNDERSTANDING OF PHYSIOLOGICAL PROCESSES

THE NERVOUS SYSTEMThe most complex and elaborate system of structures in the human bodyComposed of a group of interrelated and interrelating units that enable man to receive stimuli from the environment and to make the necessary and appropriate responses to such stimuliRegulates the behaviour of the whole individual to enable him to survive

THE NERVOUS SYSTEM

PERIPHERAL NERVOUS

SYTEMPart of the

nervous system outside the

brain and the spinal cord

which includes all the nerves

CENTRAL NERVOUS SYSTEM

Composed of the brain and the spinal cord

Central Nervous System SPINAL CORD

Composed mainly of the nerve connections running between the brain and the various parts of the body

There are 31 pairs of spinal nerves

These nerves are mixed nerves with both motor

and sensory fibersEach nerve is attached to

the cord by two roots:1. Dorsal root

Transmits sensory impulses

2. Ventral rootTransmits motor

impulses

BRAINPortion of the

nervous system that is encased in the cranial bonesWeighs 3 lbs and contains 90 % of

the body’s neuronsThe most

specialized organ in the body

THE BRAIN

BRAIN

HINDBRAIN

1. CEREBELLUM2. PONS VAROLI3. MEDULLA OBLONGATA

MIDBRAIN FOREBRAIN

1. THALAMUS2. LIMBIC SYSTEM3. CEREBRUM

•Situated at the back of and above the medulla•Composed of hemisphere•Controls body balance and keeps us right side up•Assists in coordinating our bodily movements and

keeping them rhythmic and accurate•Plays an important role in controlling the tonicity of

the skeletal muscles

Cerebellum

•Contains nerve fibers that connects both hemispheres of the cerebellum with each other as well as with nerve fibers that transmit neural impulses upward and downward within the central nervous system

•Portion of the brain with an enlarge ventral portion above the medulla

Pons Varoli

•The lowest portion of the brain and it connects with the spinal cord

•Nervous impulses travel through it to and from the higher brain centers

•It contains centers that regulate heart beat, blood pressure and breathing and it controls the activities of the internal organs

Medulla Oblonga

ta

•Brain’s major relay station connecting the lower structure of the brain and the spinal cord with the cerebrum

•Here lies the cell bodies of important connecting neurons for the various senses

•These neurons receive messages from the sense organs and send them to specific centers in the cerebrum

Thalamus

•Includes Amygdala, Hippocampus, Siptum, and portions of the Hypothalamus and Thalamus

•It performs many functions specially receiving sensory messages from the visceral organs and helps control their activities

•AMYGDALA-connected with Hypothalamus serves as the main area involved with emotions and fundamental for self-preservation, when triggered, it gives rise to fear and anxiety which leads animal to a stage of alertness

•HIPPOCAMPUS-involved with memory, especially the formation of long-term memory

Limbic System

•The largest part of the brain•Divided into two halves called the Cerebral

Hemispheres•These hemispheres contains centers for sensory

integration and for voluntary motor activity activities

•Also play important roles in governing memory and intelligence

Cerebrum

THE NEURON

The basic unit of nervous system also known as nerve cell

About 100 billion of it in the brain of an average size

variety of shape and sizes but all possess common attributes

Each of it is composed of a cell body which contains a nucleus

NERVE

A compound structure consisting of a number of neuron fibers bound together

There may be thousands of fibers in a single nerve

Each of these neuron fibers is insulated from all the others and conduct impulses independently of the others

CLASSIFICATION OF NEURONS ACCORDING TO THEIR FUNCTION

AFFERENT or Sensory Neurons Carry messages towards the central nervous

system from the receptors such as the eyes, ears, and other sense organs

EFFERENT or Motor Neurons Carry messages from the central nervous system

to the muscles and glands CONNECTING or Association Neurons

Also called as middle me between neurons Between the sensory and motor neurons Most of it found within the central nervous system

THE PERIPHERAL NERVOUS SYSTEMCOMPOSED OF NERVES THAT CONNECTS THE BRAIN AND

THE SPINAL CORD TO THE PERIPHERY OF THE BODY

•Are found outside the central nervous system

•They connect to the skin, muscles and glandsPeripher

al Nerves

•Nerves carrying sensory input to the central nervous systemAfferent nerves

•Carrying motor output away from the central nervous system to muscles and glandsEfferent nerves

THE AUTONOMIC NERVOUS SYSTEM

BEYOND OUR VOLUNTARY CONTROL AND IT CONTROLS HEART ACTION, DIGESTION, EXCRETION, SALIVATION, AS WELL AS

THOSE INVOLVED WITH SEXUAL ORGASM, PERSPIRATION

DIVIDED INTO : SYMPATHETIC

Tends to operate in stress situations Example: it increases heart beat when danger

threatens PARASYMPATHETIC

Governs regular activities Example: it slows down the heart for normal

functioning

THE ENDOCRINE GLANDS1. PITUITARY GLANDS

Sometimes called the master glands2. THYROID GLANDS

Located in the neck and produce the hormone Thyroxin3. PARATHYROID GLANDS

Secret Parathormone, a hormone necessary to control balance of various minerals in the bloodstream especially calcium

4. THYMUS Sometimes called the Gland of Childhood

5. ADRENALS Composed of two part: the Medulla (inner part) secretes

Adrenalin, and the Cortex (outer part). Adrenalin is referred to as the emergency hormone because it enables one to cope with emergency situations

6. ISLETS OF LANGERHANS Group of cells in the Pancreas which secrets Insulin that is

needed in the regulation of blood sugar by the cells7. GONADS

1. Refer to the Ovaries (produce Estrogens and Progesterone) and Testes ( produce male sex hormone Testosterone)