Biological basis of Behaviour of Humans.

Biological basis of
Behaviour
SESSION-6,7,8

Everything psychological has a biological base and
environmental and cultural influences do play a role in our
behavior

chapter outline
Neurons : building blocks of the nervous system
The nervous system : its basic structure and functions
The brain : where consciousness is
The brain And human behaviour where biology and consciousness meet
Heredity and behavior
Culture and behavior

Biological basis of behavior
Bio psychology-biological psychology
The scientific study of the biological bases of behavior and mental processes
Neuroscience : scientific study of the nervous system
Neuroscientists and bio psychologists answer questions about the relationship between
behavior, mental processes and biology
Nervous system : An extensive system or organs and nerves that are in charge of relaying
information and signals between different parts of the body.
Composed of primarily specialized cells called NEURONS. Brain is composed of 100 billion
neurons

Neurons : building blocks of the Nervous
system
Neurons : cells specialized for communicating
information ,in the nervous system the basic
building blocks of the nervous system
Dendrites : the parts of the neurons that
conduct action potential towards the cell body
Axon : the part of the neuron that conducts
the action potential away from the cell body
Glial cells : cells in the nervous system that
surround and support and protect neurons

system
A neuron is a specialized cell that is
responsible for transmitting electrical and
chemical signals in the nervous system. It is
the basic building block of the nervous system
and is composed of three main parts: the cell
body, dendrites, and axon.
The cell body, also known as the soma,
contains the nucleus and other organelles
necessary for the neuron to function. It is
responsible for synthesizing and processing
proteins and other molecules necessary for
the neuron to function properly.

system
Dendrites are branched extensions of the cell
body that receive signals from other neurons
or sensory cells. These signals are transmitted
through specialized structures called synapses,
which are small gaps between neurons that
allow for the transfer of chemical or electrical
signals.
The axon is a long, slender projection of the
neuron that carries signals away from the cell
body towards other neurons or effectors. It is
covered by a fatty substance called myelin,
which helps to insulate and speed up the
transmission of electrical signals along the
axon

system
At the end of the axon, there are specialized structures called axon terminals that release
chemical messengers called neurotransmitters into the synapse. These neurotransmitters can
either excite or inhibit the activity of the next neuron in the circuit, allowing for the transmission
of information throughout the nervous system
Overall, the unique structure of the neuron allows for the precise and rapid transmission of
information throughout the nervous system, making it a key component of many biological
processes, including perception, cognition, and behavior

Communication between neurons :
synaptic transmission
Communication between neurons occurs through a process called synaptic transmission.
Synaptic transmission involves the transfer of information between neurons through specialized
structures called synapses, which are small gaps between neurons.
When an action potential reaches the end of an axon, it triggers the release of
neurotransmitters from the axon terminal into the synapse. These neurotransmitters bind to
specialized receptors on the dendrites or cell body of the next neuron in the circuit, initiating a
new action potential in that neuron

The neurotransmitters can have either excitatory or inhibitory effects on the next neuron in the
circuit, depending on the type of neurotransmitter and the specific receptors it binds to.
Excitatory neurotransmitters increase the likelihood that the next neuron will fire an action
potential, while inhibitory neurotransmitters decrease the likelihood of firing
After the neurotransmitters have been released into the synapse, they are quickly removed from
the synapse by either reuptake back into the presynaptic neuron or enzymatic degradation by
specialized enzymes. This allows for the precise regulation of synaptic transmission and prevents
the buildup of excess neurotransmitters in the synapse

Overall, synaptic transmission plays a critical role in the communication between neurons and is
essential for many biological processes, including perception, cognition, and behavior.
Dysregulation of synaptic transmission has been implicated in a variety of neurological and
psychiatric disorder

Neurotransmitters : chemical keys to the
nervous system
Neurotransmitters location effects
acetylcholine Found throughout the central
nervous system, in the autonomic
nervous system
Involved in muscle action,
learning, and memory
nonrepinephrine Found in the neurons of the ANS Primarily involved in control and
alertness
dopamine Produced by neurons located in
the region of the brain called
substantia nigra
Involved in the movement
,attention and learning.
Degeneration of dopamine has
resulted in Parkinson’s disease.
Too much has been linked to
schizophrenia
serotonin Found in the spinal cord and in
the brain
Plays a role in regulation of mood
and in the control of
eating,sleepand arousal
GABA: gamma-amino-butyric acid Found throughout the brain and It is the major inhibitory

Drugs and neuro transmitters
Drugs can affect neurotransmitter function in a variety of ways. Some drugs mimic the effects of
neurotransmitters and bind to their receptors, while others block the reuptake or degradation of
neurotransmitters, leading to an increase in their concentration in the synapse.
Agonists : A chemical substance that mimics the action of the neurotransmitters at a receptor
site
Antagonist : A chemical substance that inhibits the effect normally produced by a
neurotransmitter

One example of a drug that mimics the effects of a neurotransmitter is nicotine. Nicotine binds
to nicotinic acetylcholine receptors in the brain, which are normally activated by the
neurotransmitter acetylcholine. This binding leads to the release of dopamine, a
neurotransmitter involved in the brain's reward system, leading to feelings of pleasure and
reward.
Another example of a drug that affects neurotransmitter function is cocaine. Cocaine blocks the
reuptake of dopamine in the synapse, leading to an increase in its concentration and prolonged
activation of the dopamine receptors. This leads to a feeling of euphoria and is the basis for the
drug's addictive properties.

Antidepressant drugs like selective serotonin reuptake inhibitors (SSRIs) work by blocking the
reuptake of serotonin in the synapse, leading to an increase in its concentration and prolonged
activation of serotonin receptors. This can help alleviate symptoms of depression, which is
thought to be related to low levels of serotonin in the brain.
Overall, drugs can affect neurotransmitter function in a variety of ways, leading to changes in
behavior and mood. Understanding the effects of drugs on neurotransmitters can help develop
new treatments for neurological and psychiatric disorders.

The nervous system : its basic structure
and its function
The nervous system is a complex network of
specialized cells and tissues that are
responsible for transmitting and processing
information throughout the body. It is divided
into two main parts: the central nervous
system (CNS) and the peripheral nervous
system (PNS).

and its function
he CNS is composed of the brain and spinal
cord, which are responsible for processing and
integrating information from the PNS and
initiating appropriate responses.
The brain is composed of different regions that
are specialized for different functions, such as
perception, movement, and cognition.
The spinal cord serves as a relay between the
brain and the PNS and is responsible for
reflexive responses to stimuli

and its function
Central nervous system: The brain is a highly
complex organ, composed of different regions
that are specialized for different functions.
The cerebrum is responsible for perception,
movement, and cognition, while the
cerebellum is responsible for motor
coordination and balance. The brainstem
controls vital functions like breathing, heart
rate, and blood pressure.

The spinal cord serves as a relay between the
brain and the PNS and is responsible for
reflexive responses to stimuli. The spinal cord
is protected by the vertebrae, which also
provide support for the body.
The CNS is composed of two main types of
cells: neurons and glial cells. Neurons are
specialized for transmitting and processing
information through electrical and chemical
signals, while glial cells provide support and
protection for neurons

Dysfunction of the CNS has been implicated in a variety of neurological disorders, including
Alzheimer's disease, Parkinson's disease, multiple sclerosis, and epilepsy. These disorders can
result from a variety of causes, including genetics, environmental factors, and injury.
Overall, the CNS plays a critical role in many biological processes, including perception,
cognition, behavior, and regulation of bodily functions. Its complex structure and functions allow
for the precise and coordinated regulation of bodily functions and behavior, making it a
fundamental component of many biological processes.

and its function
The PNS is composed of all the nervous tissue
outside of the CNS, including sensory neurons,
motor neurons, and autonomic neurons.
Sensory neurons carry information from the
body's sensory organs to the CNS, while motor
neurons carry information from the CNS to the
muscles and glands. Autonomic neurons
regulate involuntary functions like heart rate,
digestion, and breathing.

. The PNS is divided into two main branches:
the somatic nervous system and the
autonomic nervous system.
The somatic nervous system is responsible for
regulating voluntary movements and sensory
information from the body's sensory organs. It
is composed of sensory neurons that carry
information from the body to the CNS and
motor neurons that carry information from the
CNS to the muscles.

. The autonomic nervous system is responsible
for regulating involuntary functions like heart
rate, digestion, and breathing.
It is composed of two branches: the
sympathetic nervous system and the
parasympathetic nervous system.
The sympathetic nervous system is
responsible for the "fight or flight" response,
while the parasympathetic nervous system is
responsible for the "rest and digest" response.

. The PNS is composed of two main types of
cells: neurons and glial cells. Neurons are
specialized for transmitting and processing
information through electrical and chemical
signals, while glial cells provide support and
protection for neurons.
Dysfunction of the PNS has been implicated in
a variety of neurological and psychiatric
disorders, including peripheral neuropathy,
Guillain-Barre syndrome, and autonomic
dysfunction. These disorders can result from a
variety of causes, including genetics,
environmental factors, and injury.

Overall, the PNS plays a critical role in carrying
information between the CNS and the rest of
the body and for regulating bodily functions.
Its complex structure and functions allow for
the precise and coordinated regulation of
bodily functions and behavior, making it a
fundamental component of many biological
processes

and its function
The basic functional unit of the nervous
system is the neuron, which is specialized for
transmitting and processing information
through electrical and chemical signals.
Neurons communicate with one another
through specialized structures called synapses,
which are small gaps between neurons that
allow for the transfer of chemical or electrical
signals.

and its function
The nervous system plays a critical role in
many biological processes, including
perception, cognition, behavior, and regulation
of bodily functions. Dysregulation of the
nervous system has been implicated in a
variety of neurological and psychiatric
disorders, such as Alzheimer's disease,
Parkinson's disease, depression, and anxiety.
Overall, the nervous system's complex
structure and functions allow for the precise
and coordinated regulation of bodily functions
and behavior, making it a fundamental
component of many biological processes.

The endocrine system: chemical
regulators of bodily processes
The endocrine system is a complex network of
glands that are responsible for producing and
secreting hormones, which are chemical
messengers that regulate bodily processes.
The hormones produced by the endocrine
system play a critical role in regulating many
physiological processes, including growth and
development, metabolism, and reproduction

The endocrine system is composed of several
major glands, including the pituitary gland,
thyroid gland, adrenal gland, pancreas, and
ovaries or testes. Each gland produces and
secretes specific hormones that have unique
functions in the body

The pituitary gland, often referred to as the
"master gland," secretes hormones that
regulate the function of other endocrine
glands. The thyroid gland secretes hormones
that regulate metabolism, while the adrenal
gland secretes hormones that help the body
respond to stress. The pancreas secretes
hormones that regulate blood sugar levels,
and the ovaries or testes produce sex
hormones that regulate reproduction

The endocrine system works closely with the
nervous system to regulate bodily functions.
While the nervous system uses electrical and
chemical signals to communicate, the
endocrine system relies solely on chemical
signals (hormones) to transmit information.

Dysfunction of the endocrine system can lead
to a variety of disorders, including diabetes,
thyroid disorders, and hormonal imbalances.
These disorders can result from a variety of
causes, including genetics, environmental
factors, and lifestyle choices.
Overall, the endocrine system plays a critical
role in regulating many physiological processes
in the body. Its complex structure and
functions allow for the precise and
coordinated regulation of bodily processes,
making it a fundamental component of many
biological processes.

Brain : where the consciousness is ..
The human brain is a complex organ that is
responsible for controlling many physiological
and cognitive processes in the body. It is
composed of three main regions: the
cerebrum, the cerebellum, and the brainstem
The cerebrum is the largest and most complex
region of the brain, responsible for perception,
movement, and cognition.
It is divided into two hemispheres, each of
which is further divided into four lobes: the
frontal lobe, parietal lobe, temporal lobe, and
occipital lobe. Each lobe is responsible for
different functions, such as the frontal lobe's
role in decision-making and problem-solving.

Here are the basic functions of the different
lobes of the cerebrum:
Frontal lobe: The frontal lobe is located at the
front of the brain and is involved in various
functions such as reasoning, planning, problem-
solving, decision-making, personality, and
voluntary movement.
Parietal lobe: The parietal lobe is located at the
top and back of the brain and is responsible for
processing sensory information such as touch,
taste, temperature, and pressure, and spatial
orientation.

Temporal lobe: The temporal lobe is located on the sides
of the brain and is involved in processing auditory
information, visual memory, and language comprehension.
Occipital lobe: The occipital lobe is located at the back of
the brain and is responsible for processing visual
information and object recognition.
Each lobe plays a unique and important role in various
cognitive and motor functions, and they work together to
process and integrate information from the senses and
control various aspects of behavior and cognition.
Dysfunction in any of these lobes can lead to cognitive and
neurological disorders such as dementia, apraxia, or
agnosia.

Cerebellum :The cerebellum is a part of the brain that
is located at the back of the brainstem, below the
cerebrum. It is a highly convoluted structure that plays
a crucial role in motor coordination, balance, and
posture. The cerebellum receives sensory information
from various parts of the body and integrates it with
motor commands from the cerebrum to produce
smooth and coordinated movements.
The cerebellum is divided into several lobes and is
composed of a dense network of neurons, called
Purkinje cells, which are responsible for transmitting
signals from the cerebellum to other parts of the brain.
It is connected to the brainstem and the cerebrum
through a complex network of neural pathways.

Damage to the cerebellum can result in various
motor coordination and balance problems, such
as ataxia, dysarthria, and nystagmus. These
conditions can result from various factors such as
trauma, genetic disorders, infections, or
exposure to toxins.
Overall, the cerebellum is a crucial structure that
plays a vital role in the precise coordination of
movements and balance. It works closely with
other parts of the brain to integrate sensory
information and motor commands to produce
accurate and coordinated movements.

Biological basis of Behaviour of Humans.

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