The Nervous System is a network of specialized cells

and tissues that includes the brain, spinal cord, and

peripheral nerves.

It is responsible for receiving, transmitting, and

processing information within the body, like
movement, sensation and the regulation of vital
processes such as heart rate, breathing, and digestion.

It enables communication between different parts of

the body and allows organisms to interact with their
environment.

The nervous system includes the central nervous system

(CNS) and peripheral nervous system (PNS). The CNS is
made up of the brain and spinal cord, whereas the PNS is
made up of the somatic and autonomic nervous systems.
Central Neural System (CNS)
• The brain is the central information processing organ of our body, and acts as the
‘command and control system’.
• It controls the voluntary movements, balance of the body, functioning of vital
involuntary organs (e.g., lungs, heart, kidneys, etc.), thermoregulation, hunger and
thirst.
• The human brain is well protected by the skull. Inside the skull, the brain is covered by
cranial meninges consisting of an outer layer called dura mater, a very thin middle
layer called arachnoid and an inner layer (which is in contact with the brain tissue)
called pia mater.
• cranial nerves which arise from the brain and spinal nerves which arises from the spinal cord.
They are mainly part of the peripheral nervous system i.e. helps in the transmission of
information from the brain.
• Cranial nerves are a group of nerves that arises from the brain.
• The 12 pairs of nerves arise from the brain and brain stem that carries signals from the brain to
different parts of the body mainly to the head and neck.
• Vagus nerve: This nerve monitors the level of oxygen and helps us to feel the sensation of heat
or cold near the throat area.
• The spinal cord is a part of the central nervous system. It is a long pipe-like structure arising
from the medulla oblongata, part of the brain consisting of a collection of nerve fibres, running
through the vertebral column of the backbone.
• The spinal nerves consist of a group of 31 nerves.
• The spinal nerves carry messages to and from the skin of specific regions of the body called
dermatomes.

• The Somatic Nervous System is the part of the peripheral nervous system that handles voluntary
control of body movements. ... The Autonomic Nervous System is the part of the peripheral
nervous system that acts as an involuntary control system
• Organs receive nerves from both sympathetic and parasympathetic nerve fibres. They have
opposite effects on the organs if one is stimulatory, the other is inhibitory.
• The sympathetic nervous system consists of nerves arising from the spinal cord between the neck
and waist region. It prepares the body for violent actions against abnormal conditions and is
generally stimulated by adrenaline.

Effects of Sympathetic and Parasympathetic System :

Para-sympathetic
Organ Sympathetic System
system
Heart Increases heart beat Decreases heart beat
Constricts arteries & Dilates arteries &
Blood vessels
raises blood pressure. lowers blood pressure

Inhibits secretion of
Salivary glands Stimulates secretion
saliva
Relaxes urinary Contracts urinary
Urinary bladder
bladder bladder.
Promotes bile
Liver Reduces bilei secretion
secretion.
Brain

• A brain is an organ that serves as the centre of the nervous system in all vertebrate and most
invertebrate animals. The brain is the most complex organ in the body. The brain is situated in
the skull.
• The skull helps to guard the brain. The brain has the outermost region known as the cerebral
cortex.
• Weight – 1300 to 1400 gram
• It is 2% of human body.
• The Cerebrospinal Fluid (CSF) is a fluid that circulates within the skull and spinal cord, filling up
hollow spaces on the surface of the brain.
• The brain consumes most of the energy processed by the body. As well as brain is responsible for
the consumption of more oxygen.
• Likely there are 100 billion neurons are present in the brain. The brain uses 20% of body energy
to perform its task.
• Brian can be divided into four lobes. All these four lobes simultaneously work to assist other
functions of the body.
• The spinal cord is responsible for the reflex action of the body. So, the Central Nervous System is
the controller of reflex actions.
• An electroencephalogram (EEG) is a recording of brain activity. During this painless test, small
sensors are attached to the scalp to pick up the electrical signals produced by the brain. These
signals are recorded by a machine and are looked at by a doctor.
• Temporal Lobe: This is the special lobe in the brain. This lobe is situated on the front side of the
brain. It is placed in the lower side of the brain.
• This region helps to record the sensory inputs. And it helps to provide the meaning of those
sensory inputs. The temporal lobes sit behind the ears and are the second largest lobe.
• This region also helps to maintain the memory of the body. This is also used for language
interpretation.

• Frontal Lobe: This lobe is situated at the front of the

brain.
• frontal lobe is home to areas that manage thinking,
emotions, personality, judgment, self-control, muscle
control and movements, memory storage and more.
• The parietal lobes are located near the back and top of
the head.
• The parietal lobe is vital for sensory perception and
integration, including the management of taste,
hearing, sight, touch, and smell.

• Occipital Lobe: This lobe is another important lobe. As the name suggests, this lobe is used to
maintain the task related to the optical nerve. The optical nerve is used to get vision & it works
with the eye.

Parts of Brain
• It is mainly composed of neurons – the fundamental unit of the
brain and nervous system. Recent estimates have suggested
that the brain contains anywhere between 86 billion to 100
billion neurons.
• Fore Brain
• Mid Brain
• Hind Brain
Fore Brain

Fore Brain consist of 3 Parts:

1. Cerebrum
2. Thalamus
3. Hypothalamus

Cerebrum

• Largest part of human brain.

• This is the major part of the brain. The parts belonging to this category are having 2/3rd of the brain
area.
• This region helps to do the movements & regulation of temperature in the body. Also, this helps in
the thinking, reasoning & judgment process. This region also gets the nerves that help in vision,
hearing, touch, etc.
• It is responsible for memory.

Thalamus
• Receive sensory impulses from various part of the body and integrated it.
• It is consist of Pineal gland. The pineal gland is a small, pea-shaped gland in the brain,it produces
and regulates some hormones, including melatonin. Melatonin is best known for the role it plays in
regulating sleep patterns.
• The main function of the pineal gland is to receive information about the state of the light-dark
cycle from the environment and convey this information by the production and secretion of the
hormone melatonin.

Hypothalamus

• releasing hormones.
• Also, this helps to maintain body temperature, thirst & hunger.
• controlling appetite.
• managing of sexual behaviour.
• regulating emotional responses.
• It is consist of Pituitary gland.

Pituitary Gland

• The pituitary gland is a part of your endocrine system. Its main function is to secrete hormones into
your bloodstream.
• Growth hormone
• Vasopressin
• Oxytocin
• Thyroid-stimulating hormone
• Melanocyte-stimulating hormone
Mid Brain
• It is located between the hindbrain and forebrain. All
sensory and motor information that travels between the
forebrain and the spinal cord passes through the midbrain,
making it a relay station for the central nervous system.
• It basically connects the forebrain and the hind brain. It
has four corpora quadrigemina which are the reflex
centres of eye movement and auditory responses.

Hind Brain
• This is the lowest part of the brain. This helps to connect the brain with the spinal cord. There are
also three parts present in this area.
• It is composed of the medulla oblongata, the pons, and the cerebellum.

Cerebellum

• Second largest part of human brain.

• The cerebellum, which stands for “little brain”, is a
structure of the central nervous system.
• The cerebellum receives information from the
sensory systems, the spinal cord, and other parts of
the brain and then regulates motor movements.
The cerebellum coordinates voluntary movements
such as posture, balance, coordination, and
speech, resulting in smooth and balanced
muscular activity.

Pons
• The pons is the major structure of the brain stem present between the midbrain and medulla
oblongata.
• Regulating the magnitude and frequency of the respiration.
• Pons is also involved in sensations, such as the sense of taste, hearing and balance.
• It is also involved in controlling the sleep cycles.

Medulla Oblongata

• The medulla oblongata plays a critical role in transmitting signals between the spinal cord and the
higher parts of the brain and in controlling autonomic activities, such as respiration, digestion, heart
rate, functions related to the blood vessels, swallowing, and sneezing.
• This region helps to do the involuntary function. Like, this helps us in breathing, vomiting, etc.
Some Points

• Brain part for moral understanding and intelligence?

Answer: Cerebrum
• The part of the brain known as the 'small brain'?
Answer: Cerebellum
• How many spinal nerves?
Answer: 31 pairs
• The part of the brain that controls voluntary functions?
Ans: The cerebellum control voluntary movement.

Nervous System Diseases

• Parkinson’s disease:This disease is a result of the damage to the nerve cells of a region of the brain
that produces dopamine.
• Epilepsy
• Guillain- Barre syndrome
• Alzheimer’s disease