Biological Foundation of Behavior

Presented by: DR. RHEA LOWELLA SANTILLAN FISER, RPsy, Rpm, CSIOP
BIOLOGICAL
FOUNDATION
OF BEHAVIOR

Learning Objectives
1. Identify the parts and functions of the main
divisions of the nervous system.
2. Explain how hormonal imbalance affects
one’s behavioral responses.
3. Describe the anatomy and functions of the
major parts of the brain.
4. Trace the pathway of the nerve impulse
from the receptor cells to the effectors.
5. Appreciate the significance of the nervous
system in integrating the different bodily
activities.
Presented by:
DR. RHEA LOWELLA SANTILLAN FISER, RPsy, Rpm, CSIOP

WHAT IS NERVOUS SYSTEM?
The nervous system
comprises of two
main divisions:
1. The Central
Nervous System
(CNS)- consist of
the brain and the
spinal cord

2. The Peripheral
Nervous System
(PNS) – composes
all the nerve
fibers that
connect the
receptors to the
central nervous
system.

NERVOUS SYSTEM
❑CONTROLS ALL OUR
BODY ACTIVITIES AND
BEHAVIORAL
RESPONSES.
❑IT IS MADE UP MAINLY
OF NEURON OR
NERVE CELLS WHICH
NUMBERS TO ABOUT
ONE HUNDRED
BILLION.

The Neuron or
Nerve Cell
❑ the basic structural and
functional unit of the
nervous system
Three Parts of Neuron
✓ CELL BODY
✓ DENDRITES
✓ AXON

The Neuron

Presented by: DR. RHEA LOWELLA G.
SANTILLAN, CSIOP, Rpm
The Neuron

The nervous system
comprises of two main
divisions:
1. The Central Nervous
System (CNS) – consist of
the brain and the spinal
cord
2. The Peripheral Nervous
System (PNS) – composes
all the nerve fibers that
connect the receptors to
the nervous system and
which further connects
the central nervous system
to the effectors

The Neuron
Neurons are grouped
into three according to
their functions:
1. Sensory or
afferent neurons
carry messages or
nerve impulses from
the sense organ
toward the brain/
central nervous system

2. Motor or efferent
neurons carry messages or
nerve impulses away from
the brain , that is , it goes
to the effectors like the
muscles and glands
3. Inter-neurons ,
connector neurons or
association neurons carry
messages or nerve
impulses within the brain
or central nervous system

Characteristics of
Neuron
1. Irritability – is the
ability of neurons
to react to external
stimulation
2. Conductivity –
ability of neurons
to transmit nerve
impulses up to the
end of the nerve
fiber

Stimulus refers to
anything that
excites or initiates
an activity. Once a
stimulus is received
by the receptor, it
leads to the
creation of
electrical signals
known as nerve
impulses or
messages

Sending of a nerve impulse or ‘firing’
of a neuron down the axon from the
end of one neuron is called action
potential.

.
Before a nerve impulse
reaches its destination, it
has to pass through several
specialized nerve
boundaries or junctures
called synapses.
Once the nerve impulse or
action potential reaches
the tip of the axon, it
causes the release of a
chemical known as
transmitter into the
synapse because of this, the
receptor sites of the next
receiving neurons ‘catch’ or
bind with the chemical.

Laws governing the Neuron
1. All or Nothing Law- states that
it is either that neuron reacts
or not at all, but if it does, it
reacts with fullest strength
1. Law of Dynamic Polarity-
states that nerve impulses
travel only in one direction
from neuron to neuron

NERVOUS SYSTEM

The central nervous
system is situated
centrally. It is
basically made up
of the brain and
the spinal cord. As
such, the central
nervous system
serves as the
integrating
mechanism of the
entire human body.

Central Nervous System

BrainThe brain floats on a bath of
cerebrospinal fluid (CSF) and it is
protected by the skull.
It is jelly-like and extra soft weighing
about 1,400 grams.
The brain is the ‘master organ’ and it
is the busiest part of the body.
It controls and directs all activities in
the nervous system.
As the master or the chief organ, the
brain is responsible for the
integration of the central nervous
system (CNS) and peripheral
nervous system (PNS).

The brain has three
major divisions:
1. Forebrain- consists of
the cerebrum,
thalamus, and
hypothalamus

Cerebru
m
is the most
complex and
largest part of
the brain.
● It is considered
as the ‘seat of
consciousness’

CEREBRUM
It consists of the right hemisphere and
left hemisphere..

ACTIVITY
TIME:
GET ¼ SHEET
OF PAPER
TEST A B C
1
2
2.1
2.2
2.3
2.4
3
4
5
6
6.1
6.2
6.3
SAMPL
E ONLY

In which direction is the dancer
turning?
A B
1.

Choose the color, not word.  
You have 4 seconds for each task
GREEN
VIOLETGREEN
2.1

REDORANGE
RED
2.2

MAROONBLUE
2.3
BLUE

PINKBROWN
PINK
2.4

Of the following, which picture appeals
to you most
C

The picture is most similar to:

Of the following, which picture best fits
the theme of friendship

TEST 6

Put your hand on your head 
 
Which hand did you use?
LEFT RIGHT

Cross your legs 
 
Which leg is on top?

Look at an object and close one eye 
 
Which eye is still open?

INTERPRETATION

ANSWER
Test 1: Dancer
According to how your brain
works, the dancer will either
turn clockwise or counter
clockwise.
If she turns clockwise,
then you use predominantly the
right side of your brain and you
are more than likely right-
handed.

ANSWER
Test 2: Color Test
2.1 B
2.2 A
2.3 B
2.4 A

ANSWER
Test 2: Color Test
Conflict:
The right side of the brain wants to pick
the color that matches the word:
The left side of the brain wants to
chose the word written.
When you make a mistake, that the left side of the brain
in action

ANSWER
Test 3: PICTURE
ANSWER A:
If you choose this picture, the left side of your
brain is most dominant. This is because the circle
has a simple and recognized shape that is easy to
define

ANSWER
Test 3: PICTURE
ANSWER B
This shape is compromise between the simple first
picture and the wild picture in answer C.
The figure is more complex and fascinating, yet self
contained.
Therefore, it is choses most frequently by people
whose brain halves are equally pronounced.

ANSWER
Test 3: PICTURE
ANSWER C
If you chose this picture, the right side of your brain
is most dominant. The figure appears incomplete,
without shape or direction.
It offers the possibility of development.

ANSWER 
Test 4: SIMILAR TO
ANSWER A
Here, the figures are also equal in size. They differ
greatly, however, in color.
This visual factor is the result of the dominance of
the left side of your brain

ANSWER 
Test 4: SIMILAR TO
ANSWER B
The figures are equal in size and relatively
equal in color.
If you chose answer A, the right side of your
brain is most dominant.

ANSWER 
Question 4: SIMILAR TO
ANSWER C
Here, the original picture was broken down into
fragments.
If you chose this answer, the right side of your
brain is most dominant.

ANSWER 
Test 5: FRIENDSHIP
ANSWER A
The circles in this figure are loosely grouped,
but not entirely unstructured.
If you choose this answer, no side of your brain
claims dominance.

ANSWER 
Question 5: FRIENDSHIP
ANSWER B
The arrangement of circles in this figures is the
typical expectation of a friend circle.
This visual factor is the result of the dominance
of the left side of your brain

ANSWER 
Question 5: FRIENDSHIP
ANSWER C
In this image, the circles are distanced equally
from one another.
Answer C is chosen most frequently by those
whose right brain half dominates

ANSWER 
Test 6, 7, and 8
If your in right –brain mode,
You will use your left hand, left leg or left eye.
If your in left-brain mode, you will use your right hand,
right leg
or right eye.
In these cases, the right side of the body is controlled by the
left side of the brain and vice versa.

CEREBRUM
Each of the
cerebral
hemispheres is
subdivided into
four lobes which
are frontal lobe ,
temporal lobe,
parietal lobe, and
occipital lobe.

Lobes of the Brain

Thalamus
It is found right on
top of the
midbrain. This large
bundle of nuclei
serves as a relay
center of the
impulses being sent
to the brain areas.

Hypothalamus
✓It is located under
the thalamus .
✓It is considered as
the seat of
emotion.

The reticular
activating system
(RAS) controls
our level of sleep
and arousal
through the
reticular
formation that is
embedded within
its central core.

It plays important role
in regulating the
state of arousal or
consciousness.
It screens out all
background
information to enable
us to sleep and it also
enables us to wake up
sleep.

The limbic
system is
made up of
complex
structures
located around
the thalamus
just beneath
the cerebrum.

Also found here is
the
hippocampus
(SEA HORSE)
which is
responsible in
changing short-
term memories
into long-term
memories.

Amygdala
(ALMOND) is another
important part of
limbic system which
is believed to cause
aggressive behavior
among the animals.

The midbrain serves as the bridge between
the hindbrain and the forebrain.

It is responsible in
linking the
sensory and
motor pathways
between the
upper and the
lower parts of
the nervous
system. Some
parts of the
midbrain are
also involved in
auditory and
visual activities.

The midbrain serves as
the bridge between
the hindbrain and the
forebrain.
Hindbrain is composed
of the pons , medulla
oblongata , and the
cerebellum. It is
connected to the
spinal cord.

• The pons is
located in front
of the cerebellum
and it is made up
of mostly of the
nerve fibers
running from one
part of the brain
to the others.

• The medulla
oblongata is
quite small , about an
inch long just above
the spinal cord. It
regulates the
involuntary muscles
responsible for our
heartbeat , rate of
breathing or
respiration ,
swallowing and
movements of the
stomach and
intestine.

The cerebellum or
‘little brain’ has
two hemispheres. It
is connected to the
back of the brain
stem. It is involved
in the coordination
of voluntary motor
activities. It
maintains our body
balance and
posture.

Spinal cord
The spinal cord is a
long and stem-like
structures running
down the vertebral
column.
It is composed of
nerves that lead to
and from the
brain..

•When you
demonstrate
sudden
withdrawal of
hand from
pain or blink
to loud
sound , you
are
experiencing a
more complex
reflex called
polosynaptic
reflexes.

There are two kinds of reflexes which are:
Monosypnaptic reflex takes place due to direct
connection between a sensory neuron and a
motor neuron , without intervening interneurons.

Monosypnaptic
reflex
It consists only one
synapse between
what you feel or
a sensory input.
An example of
this is the ‘knee-
jerk’ or patellar
reflex where
both kinds of
neurons involved
in such reflex are
found in the
spinal cord.

SYMPATHETIC NERVOUS
SYSTEM
It covers the activities
of the internal organs
within the thoracic-
lumbar regions. It also
activates and speeds
up life activities. It
prepares ourselves into
vigorous actions like
those of fight or flight
reactions to stress.

B. Autonomic or Visceral nervous system is
composed of the sympathetic system and
parasympathetic system. This division of
nervous system is responsible for all
involuntary movements within the body
that keep us alive.

Parasympathetic
System covers the
cranial sacral
regions. It slows
down the life
activities. This
system restores
the body – stored
energy, thus,
calming down the
body after
resolving a
stressful and
emergency
situation.

Endocrine
System
It is involved
with the
process of
maintaining
the
biochemical
equilibrium in
the body or
homoestasis.

Endocrine
System

The Endocrine Glands
1. Pituitary Gland, also
known as ‘the master
gland’ because it
secretes a number of
hormones that affect
the activities of
almost all the
endocrine glands

⬧ Acromegaly
characterized by an
overgrowth of
certain parts of the
bones like
individuals with a
hunchback.

Pineal Gland also
known as ‘gland of
childhood’ is
located in the head
adjacent to the
pituitary gland. It
controls the
activity of the
reproductive
organs. It secretes
the hormone,
melatonin.

3. Thyroid Gland is
the butterfly – shape
gland located at the
base and anterior
part of the throat. It
secretes thyroxine
and idothyroxine
which affect growth
and metabolism

Cretinism
(characterized to
be retarded
physical and
mental
development
during childhood

Myxedema
(characterized by
gain in weight,
thickening of the lips
slowing of motor
movements, and
yellowing of the skin
during adulthood)

• 4. Parathyroid
Glands are pea-
shaped gland
located at the
posterior of the
thyroid gland. It
secretes
parathormone
which controls the
calcium level in
the blood

5. Thymus Gland also
called the ‘gland of
babyhood’ keeps an
individual
‘childish’. It is
located above chest
cavity. It secretes
hormone, thymosin.
This gland inhibits
sexuality during the
childhood years.

6. Adrenal Gland
is located at the
upper end or tip
of each kidney.

Islets of
Langerhans ,
these are small
bodies made up
of clusters of
special cells
scattered all over
the pancreas.

8. Gonads / Sex
Glands
A. Testes which
is located in the
scrotal sac and
secretes the
hormone.
Testosterone is
responsible for
the appearance
of secondary
sexual
characteristics.

B. Ovaries are
located
within the
abdominal
cavity. The
ovaries
secrete two
hormones,
estrogen and
progesteron
e

Dr. Rhea Lowella Santillan-Fiser, RPsy, Rpm, CSIOP
Professor
For more questions you can email me through
rheasantillan@live.com
Youtube Channel
DR. Rhea Lowella Santillan Fiser
https://www.youtube.com/channel/UChWhr-Lk0o5mo6mXQR-
SGOA

Biological Foundation of Behavior

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