biological basis of human behavior

BIOLOGICAL

BASIS OF

HUMAN

BEHAVIORDr. Jayesh Patidar

www.drjayeshpatidar.blogspot.com

INTRODUCTION

• The biology of behavior is the study of behavioral

functions of the nervous system, particularly the

brain.

• „Physiological psychology‟ is that branch of

psychology which seeks to determine how activity in

the nervous system is related to behavior & the mind.

• Human behavior involves the body-mind interaction of

the various bodily factors. The most important are:

1. The sense organs, called receptors.

2. The muscles & endocrine glands called effectors

3. The nervous system known as the connecting or

integrating mechanism.

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RECEPTORS

• Behavior in all its forms &

shapes has definitely a

biological or physiological base.

• The behavior is based on the

various stimuli present in the

external environment & lying

within our body.

• The stimuli in the form of

various sensory experiences are

received by our sensory

systems known as receptors


• External receptors are those

sensory mechanisms that

help us make contact with the

outer world, for example,

eyes, ears, nose, tongue &

skin.

• The specific receptor cells for

receiving the external stimuli

lie within these sensory

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External Receptors

RECEPTORS

• These receptors are associated

with the internal stimuli present in

our body.

• They are responsible for feelings

of pain, hunger or nausea.

• Another variety of these internal

receptors helps us in maintaining

balance, bodily posture &

equilibrium & also exercise

control over the muscle.


Internal Receptors

RECEPTORS

• Our sense organs help in

assimilating knowledge of the

world around us. Each of our

sense organs has a distinct

function to perform.

• Sense organs consist of

receptors, which are specialized

sensitive cells associated with

ending of sensory nerve fibers.

These receptors are stimulated

by objects outside the body &

also by internal conditions.


Sense Organs

RECEPTORS

• When the receptors

are not functioning

properly, they lead to

sensory defects or

disorders- visual,

auditory, cutaneous,

olfactory, gustatory,

kinaesthetic & static

disorders.


Sense Organs Count…

RECEPTORS

EFFECTORS

• Effectors are termed as the organs of responses.

• What is received through the sensory organs in

the form of sensory input is responded through

bodily reactions & motor activities carried out

through muscles & glands, particularly the

hormones secreted by the ductless gland which

are responsible for most of our behavior patterns.

• The under-activity or over-activity of these

glands, causes deficiency or excess of hormonal

secretion.

• This affects the entire personality make-up of the

individual.2/6/2015 8www.drjayeshpatidar.blogspot.com

• Our behavior & activity involves

movement of different parts of

our body.

• Muscles help the organism to

carry out motor activities in

order to respond to various

stimuli.

• There are mainly three types of

muscle – smooth muscles,

cardiac muscles & skeletal

muscles.2/6/2015 9www.drjayeshpatidar.blogspot.com

Muscles

EFFECTORS

• Glands play an important role in

human behavior.

• They also assist in the digestion

of food, elimination of waste

products, production &

prolongation of emotion states &

regulation of metabolism of the

body.

• There are two types of glands:

1. Duct glands

2. Ductless or endocrine glands.2/6/2015 10www.drjayeshpatidar.blogspot.com

Glands

EFFECTORS

• The duct glands release their chemical

secretion through little ducts or tubes into the

body cavities or on the surface of the body.

Some of the duct glands are

Salivary glands

Gastric glands

Sweat glands

Lacrimal glands

Kidney

Sex glands


Glands Count…

EFFECTORS

• The ductless or endocrine glands secrete chemical

substances called hormones.

• The hormones are released into blood stream & are

carried to all parts of the body.

• They play a vital role in the determination of human

personality.

• They affect the development of the body, general

metabolism, mental development, development of

secondary sex characteristics & emotional behavior.

• The endocrine glands are:


Glands Count…

EFFECTORS

The pituitary

Thyroid

Parathyroid

Adrenals

Male sex glands or gonads

Pancreas

CONNECTORS

• Connectors or adjustors help in regulating,

controlling or coordinating the activities of

receptors & effectors

• The ability to play a piano drive a car or hit a

tennis ball depends on muscle co-

ordination.

• It is necessary for the body to provide

messages to the muscles to coordinate.

• These messages are passed through

specialized cells called neurons.


• A nerve cell with all its branches is

called a neuron.

• These are the basic elements of

the nervous system.

• A neuron has a nucleus, a cell

body & a cell membrane to

enclose the whole cell body called

dendrites.

• Their role is to receive message

through electrical impulses from

the sense organs or adjacent

neurons & carry them to the cell

body.2/6/2015 14www.drjayeshpatidar.blogspot.com

Neuron

CONNECTORS

• The messages from the cell body further travel

the length of a nerve fiber known as the axon.

• There are three types of neurons.

The sensory neurons – they help in the process

of sensation & perception.

The motor neurons – they are responsible for

physical movements & activation of glands.

The inter-neurons or association neurons – they

carry signals in the form of memories & thoughts

& add reflex or automatic activities.


Neuron Count…

CONNECTORS

• Neurons are the receivers & transmitters of

messages.

• These messages are always in the form of

electrochemical impulses.

• There is a fluid-filled space called the synapse

between the axon of the neuron & the receiving

dendrite of the next neurons.

• Enlargements of the axon endings of the

transmitting neurons called boutons, contain

neuro-transmitter chemicals which are stored in

small vesicles.2/6/2015 16www.drjayeshpatidar.blogspot.com

Neural Impulse

CONNECTORS

• Neurotransmitters are a particularly important link

between the nervous system & behavior.

• Deficiency or an excess of a neurotransmitter can

produce severe behavior disorders.

• Some major neurotransmitters are:

Acetylcholine

Glutamate

Gama-amino butyric acid (GABA)

Dopamine

Serotonin

endorphins2/6/2015 17www.drjayeshpatidar.blogspot.com

Neurotransmitters

CONNECTORS

NERVOUS SYSTEM

• The human nervous system can be divided

into two parts


Central Nervous

System

It constitutes of the

brain & spinal cord

Peripheral Nervous

System

It constitutes of the

somatic system &

autonomic system

NERVOUS SYSTEM

BRAIN

Forebrain

- Thalamus

- Hypothalamus

- Limbic system

- Cerebral cortex

Midbrain

Hindbrain

- Medulla

- Pons

Cerebellum


CENTRAL NERVOUS SYSTEM

NERVOUS SYSTEM



• It‟s important structures are

thalamus, hypothalamus,

limbic system & the

cerebrum.

• All sensory impulses pass

through from thalamus to the

higher centers.

• The thalamus has plays a

role in the control of sleep &

alertness.

The forebrain

NERVOUS SYSTEM



• It lies below the thalamus.

• It exerts a key influence on all

kind of emotional as well as

motivational behavior.

• Centers in the hypothalamus

have control over the important

body processes like eating,

drinking, sleeping, temperature

control & sex.

Hypothalamus

NERVOUS SYSTEM



• It consists of structures in the

thalamus, hypothalamus &

cerebrum which form a ring

around the lower part of the

forebrain.

• The limbic system often called the

emotional brain, functions in

emotional aspects of behavior

related to survival, memory, smell,

pleasure & pain, rage &

aggression, affections, sexual

desire etc.

The limbic system

NERVOUS SYSTEM



• It is most complex & largest part

of the brain.

• The cerebrum is covered by a

thick layer of tightly packed

neurons called the cerebral

cortex.

• It is divided into two

hemispheres; the left & right

hemispheres.

The Cerebrum

NERVOUS SYSTEM



• It is concerned with the relaying of

messages particularly those related to

hearing & sight to higher brain centers.

• One of its important structures is known as

Reticular Activating System (RAS).

• With the help of this structure an individual

is able to decide which impulses should be

registered consciously & which should be

rejected.

The midbrain

NERVOUS SYSTEM



• It is composed of three structures, the medulla, the

pons & the cerebellum.

• Medulla controls breathing & many important

reflexes & it also regulates the digestion, respiration

& circulation.

• The pons assists in breathing, transmitting impulses

from the cerebellum to the higher brain regions.

• Cerebellum is responsible for body balance & the

coordination of body movements like dancing,

typing, playing, etc.

The midbrain

NERVOUS SYSTEM



• It works as a channel of communication from

& to the brain.

• It is a rope like structure made up of long

round nerve fibers.

• It also works as an organ for effective reflex

actions like withdrawal of the hand when

something is hot.

• These reflex actions are almost automatic in

nature.

Spinal Cord

NERVOUS SYSTEM



Localization of mental functions in the brain

NERVOUS SYSTEM


PERIPHERAL NERVOUS SYSTEMPeripheral Nervous System

Made up of long axons & dendrites, it contains all

parts of the nervous system other than the brain

& spinal cord

Somatic division

(Voluntary)

Parasympathetic division

Acts to clam the body after an emergency

situation has engaged the sympathetic

division, provides a means for the body to

maintain storage of energy sources.

Automatic division

(Involuntary)

Acts to prepare the body in stressful

emergency situations, engaging

resources to respond to a threat

Sympathetic division

BRAIN AND BEHAVIOR


• The entire behavior is effectively managed &

controlled by the co-ordination & functioning

of the nervous system.

• How we will behave in a particular situation

depends upon the judgment of our brain.

• The sense impressions, which are received

through the sense organs, do not bear any

significance unless they are given a meaning

by the nervous system.


Integrative function of the Nervous System

Localization of mental functions in the brain

BRAIN AND BEHAVIOR


Importance of knowledge of the nervous system

& glands to a nurse

BRAIN AND BEHAVIOR

• It helps the nurse to understand the physiological

basis of patient behavior.

• It helps the nurse to understand how glandular

secretions influence personality.

• It helps the nurse to understand the various

diseases of nervous system & glands & their

effects on human behavior.

• It helps the nurse in understanding the process

of attainment of knowledge & learning, by

knowing this she can make desirable changes.


LEVELS OF FUNCTIONING

• The individual functions at three levels:

1. Conscious level

2. Preconscious level

3. Unconscious level


1. Conscious Level

BRAIN AND BEHAVIOR

• It constitutes all those experiences of which an

individual is immediately aware of at any

particular time.

• It consists of his current thoughts & experiences.

• For example; attending to something, observing,

thinking, reasoning, judging, imagining.

• Every conscious experience has three aspects

cognitive, affective & conative or knowing



2. Pre-conscious Level

BRAIN AND BEHAVIOR

• Pre-conscious thoughts are memories of which

an individual may not be aware of, but can recall

to mind when he wishes.

• Pre-conscious mental process are also called

subconscious mental process.

• Foe example; sometimes we forget a name in

the course of a conversation. We do not become

conscious of it, we make an effort & try to

recollect, after sometime, the name which we

were in search of, springs all at once into

consciousness.



3. Unconscious Level

BRAIN AND BEHAVIOR

• Experiences those which are not easily reached

by our conscious thoughts as the pre-conscious

experiences.

• We are not aware of our unconscious functions &

cannot understand them at any one time.

• Unconscious experiences cannot become

conscious but must be inferred from our

behavior.

• For example; certain things make you very angry

but you cannot understand why you become so

angry



BODY-MIND RELATIONSHIP• Psychology studies human behavior which

involves both body & the mind.

• They are interrelated & interact upon each other.

• Mental functions & physical states affect each

other.

• Body & the mind are two aspects of the living,

dynamic & adjusting personality.

• Mind is regarded as a function of the body; it does

not exist apart from the body.

• It is some total of various mental process such as

observing, knowing, thinking, reasoning, feeling,

imagining, remembering, judging & others.


Modulation Process in Health and Illness

Effects of bodily conditions on mental functioning

• Increased blood pressure causes mental

excitement.

• Severe pain reduces the concentration level

• Chronic illness causes depression

• Malfunctioning of the endocrine glands for

example, may exert a full influence on one‟s

personality, resulting in lethargy, nervous

tension, etc.

BODY-MIND RELATIONSHIP


Modulation Process in Health and Illness

Effects of mental conditions on bodily functioning

• Unpleasant emotions like fear, anger & worry

cause irritability, insomnia, headache etc. mental

processes are intimately connected to brain or

cortical processes.

• Emotional conflicts are responsible for peptic

ulcer, ulcerative colitis etc.

• Deep thinking & concentration can cause

physical strain.

BODY-MIND RELATIONSHIP


Heredity

• Heredity is considered as “the sum total of inborn

individual traits”.

• Biologically, it has been defined as “the sum total

of traits potentially present in the fertilized ovum”.

• According to Douglas & Holland “one‟s heredity

consists of all the structures, physical

characteristics, functions or capacities derived

from parents, other ancestry or species”.

HEREDITY AND ENVIORNMENT


Heredity

• Heredity is the basis for the development of

human personality.

• Many aspects of human behavior & development

ranging from physical characteristics such as

height, weight, eye & skin color, the complex

patterns of social & intellectual behavior are

influenced by person‟s genetic endowment.


Genetics and Behavior


Environment

• The child inherits the traits & characteristics of

his parents & forefathers through genes at the

time of conception.

• After conception, how he develops is the

outcome of the interaction between his heredity

& environment.

• Environment covers the social, moral,

economical, political, physical & intellectual

factors which influence the development of the

individual from time to tiem.



Environment

• The environment is every thing that affects the

individual except his genes.

- (Boring, Langfield and Weld)

• Environment covers all the outside factors that

have acted on the individual since he began life.

- (Woodworth)


Definition


Environment

1. Intercellular environment: It relates to embryonic

development.

2. Intrauterine environment: It shelters the baby

during prenatal life.

3. External environment: It divided into three kinds:

a) Physical environment

b) Biological environment

c) Psychosocial environment


Types of Environment


Thank You

biological basis of human behavior

Education

sensory organs

behavior activity

sense organs

muscles glands

sensory systems

external receptors

internal receptors

sensory defects