The nervous system of vertebrates (including humans) is divided into the central nervous system (CNS) and the peripheral nervous system (PNS). The (CNS) is the major division, and consists of the brain and the spinal cord. The spinal canal contains the spinal cord, while the cranial cavity contains the brain.

1. Nervous System
Mohammad Arman
Department of Pharmacy, IIUC

2. Nervous System
• The nervous system of vertebrates (including humans) is
divided into the central nervous system (CNS) and the
peripheral nervous system (PNS). The (CNS) is the major
division, and consists of the brain and the spinal cord. The
spinal canal contains the spinal cord, while the cranial cavity
contains the brain.
• Nervous system is body’s command center. Originating from
brain, it controls movements, thoughts and automatic
responses to the world. It also controls other body systems and
processes, such as digestion, breathing and sexual
development (puberty). Diseases, accidents, toxins and the
natural aging process can damage nervous system.

3. Affects of Nervous System
Nervous system affects every aspect of your health, including
your:
• Thoughts, memory, learning, and feelings.
• Movements, such as balance and coordination.
• Senses, including how your brain interprets what you see,
hear, taste, touch and feel.
• Sleep, healing and aging.
• Heartbeat and breathing patterns.
• Response to stressful situations.
• Digestion, as well as how hungry and thirsty you feel.
• Body processes, such as puberty.

4. Structure and function of nervous system

5. Overview of NS

6. Neuron
• Neurons are the building blocks of the nervous system. They
receive and transmit signals to different parts of the body. This
is carried out in both physical and electrical forms. There are
several different types of neurons that facilitate the
transmission of information.

7. Parts of Neuron
Following are the different parts of a neuron:
1. Dendrites: These are branch-like structures that receive messages
from other neurons and allow the transmission of messages to the cell
body.
2. Cell Body: Each neuron has a cell body with a nucleus, Golgi body,
endoplasmic reticulum, mitochondria and other components.
3. Axon: Axon is a tube-like structure that carries electrical impulse
from the cell body to the axon terminals that pass the impulse to
another neuron.
4. Synapse: It is the chemical junction between the terminal of one
neuron and the dendrites of another neuron.

8. Neuron Types
• There are three different types of neurons:
1. Sensory Neurons: The sensory neurons convert signals from the
external environment into corresponding internal stimuli. The
sensory inputs activate the sensory neurons and carry sensory
information to the brain and spinal cord. They are pseudounipolar
in structure.
2. Motor Neurons: These are multipolar and are located in the
central nervous system extending their axons outside the central
nervous system. This is the most common type of neuron and
transmits information from the brain to the muscles of the body.
3. Interneurons: They are multipolar in structure. Their axons
connect only to the nearby sensory and motor neurons. They help
in passing signals between two neurons.

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10. Neuroglia
• Neuroglia, also called glial cell or glia, any of several types of
cell that function primarily to support neurons. The term
neuroglia means “nerve glue.” In 1907 Italian biologist Emilio
Lugaro suggested that neuroglial cells exchange substances
with the extracellular fluid and in this way exert control on the
neuronal environment.
• Neuroglia are a large class of neural cells of ectodermal
(astroglia, oligodendroglia, and peripheral glial cells) and
mesodermal (microglia) origin. Neuroglial cells provide
homeostatic support, protection, and defense to the nervous
tissue.

11. Types and Function

12. Components of NS

13. Central Nervous System
• The central nervous system (CNS) consists of the brain and
spinal cord. It controls things like thought, movement, and
emotion, as well as breathing, heart rate, hormones, and body
temperature.
• Each nerve has a protective outer layer called myelin. Myelin
insulates the nerve and helps the messages get through.
It composed of two major interconnected organ:
1. The brain
2. The spinal cord

14. Brain

15. Brain
• Parts of the body:
Cerebrum: The cerebrum (front of brain) comprises gray matter
(the cerebral cortex) and white matter at its center. The largest
part of the brain, the cerebrum initiates and coordinates
movement and regulates temperature. Other areas of the
cerebrum enable speech, judgment, thinking and reasoning,
problem-solving, emotions and learning. Other functions relate to
vision, hearing, touch and other senses.
Cerebral Cortex: Cortex is Latin for “bark,” and describes the
outer gray matter covering of the cerebrum. The cortex has a
large surface area due to its folds, and comprises about half of the
brain’s weight.

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Brainstem: The brainstem (middle of brain) connects the
cerebrum with the spinal cord. The brainstem includes the
midbrain, the pons and the medulla.
I. Midbrain: The midbrain (or mesencephalon) is a very complex structure
with a range of different neuron clusters (nuclei and colliculi), neural
pathways and other structures. These features facilitate various functions,
from hearing and movement to calculating responses and environmental
changes.
II. Pons: The pons is the origin for four of the 12 cranial nerves, which
enable a range of activities such as tear production, chewing, blinking,
focusing vision, balance, hearing and facial expression.
III. Medulla: At the bottom of the brainstem, the medulla is where the brain
meets the spinal cord. The medulla is essential to survival. Functions of
the medulla regulate many bodily activities, including heart rhythm,
breathing, blood flow, and oxygen and carbon dioxide levels.

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Cerebellum: The cerebellum (“little brain”) is a fist-sized portion
of the brain located at the back of the head, below the temporal
and occipital lobes and above the brainstem. Like the cerebral
cortex, it has two hemispheres. The outer portion contains
neurons, and the inner area communicates with the cerebral
cortex. Its function is to coordinate voluntary muscle movements
and to maintain posture, balance and equilibrium. New studies
are exploring the cerebellum’s roles in thought, emotions and
social behavior, as well as its possible involvement in addiction,
autism and schizophrenia.

18. Gray matter and white matter?
Gray and white matter are two different regions of the central
nervous system. In the brain, gray matter refers to the darker,
outer portion, while white matter describes the lighter, inner
section underneath. In the spinal cord, this order is reversed: The
white matter is on the outside, and the gray matter sits within.

19. Deeper Structures Within the Brain
Pituitary Gland: Sometimes called the “master gland,”. The pituitary
gland governs the function of other glands in the body, regulating the
flow of hormones from the thyroid, adrenals, ovaries and testicles. It
receives chemical signals from the hypothalamus through its stalk and
blood supply.
Hypothalamus: The hypothalamus is located above the pituitary gland
and sends it chemical messages that control its function. It regulates
body temperature, synchronizes sleep patterns, controls hunger and
thirst and also plays a role in some aspects of memory and emotion.
Pineal Gland: The pineal gland is located deep in the brain and
attached by a stalk to the top of the third ventricle. The pineal gland
responds to light and dark and secretes melatonin, which regulates
circadian rhythms and the sleep-wake cycle.
Hippocampus: It supports memory, learning, navigation and
perception of space. It receives information from the cerebral cortex
and may play a role in Alzheimer’s disease.

20. Spinal Cord
• The spinal cord is a long, tube-like band of tissue. It connects
your brain to your lower back. Your spinal cord carries nerve
signals from your brain to your body and vice versa. These
nerve signals help you feel sensations and move your body.
Any damage to your spinal cord can affect your movement or
function.
• In most adults, your spinal cord is about 18 inches (45
centimeters) long.
What is the purpose of the spinal cord?
I. Control body movements and functions.
II. Report senses to brain.
III. Manage your reflexes.

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What are the main parts of the spinal cord?
Spinal cord has three main parts:
1. Cervical (neck).
2. Thoracic (chest).
3. Lumbar (lower back).
What tissues and fluids make up the spinal cord?
Like brain, layers of tissue called meninges cover the spinal cord.
These protective tissues include:
1. Dura mater: The outer layer that protects your spinal cord from
injury.
2. Arachnoid mater: The middle layer between the epidural and
subarachnoid space.
3. Pia mater: The inner layer that covers your spinal cord.

22. Peripheral Nervous System (PNS)
Peripheral nervous system (PNS) is that part of your nervous
system that lies outside brain and spinal cord. It plays key role in
both sending information from different areas of body back to
brain, as well as carrying out commands from your brain to
various parts of your body.
The four primary functions of the PNS are to:
i. Control autonomic body functions
ii. Control motor movements
iii. Digestion
iv. Relay sensory information to the central nervous system

23. Cranial Nerves
The cranial nerves are a set of 12 paired nerves in the back of
your brain. Cranial nerves send electrical signals between your
brain, face, neck and torso. Your cranial nerves help you taste,
smell, hear and feel sensations. They also help you make facial
expressions, blink your eyes and move your tongue.

24. Overview of Autonomic NS

25. Somatic Nervous System
• The Somatic Nervous System is the part of the peripheral nervous
system that handles voluntary control of body movements
• In somatic nervous system, In the process of voluntary movement,
sensory neurons carry impulses to the brain and the spinal cord.
After processing, a signal is sent back to the skeletal muscles,
organs, and skin by way of the somatic motor neurons. The second
function of the somatic nervous system is the process of the reflex
arc.

26. Autonomic Nervous System
• The Autonomic Nervous System is the part of the peripheral
nervous system that acts as an involuntary control system
(below the level of consciousness), and controls visceral
functions.
• The autonomic nervous system (ANS) is still controlled by the
brain too -- but is not conscious. The brain's hypothalamus is
required to send signals to the heart, your glands, breathing,
digestion etc.

27. Somatic Vs. Autonomic NS