By:M. Thiru murugan Unit – 11: Types of nerves- structure and functions Brain and cranial nerves. Spinal cord and motor and sensory pathways of the spinal cord, autonomic nervous system. Nervous system: Nervous system is one of vital system in our body which control and coordinate all the functions of body parts. Classification: Central nervous system (CNS) Peripheral nervous system (PNS) 1. Central nervous system (CNS): brain and spinal cord 2. Peripheral nervous system (PNS): Somatic nervous System & Autonomic nervous system (ANS) Central Nervous System (CNS): The central nervous system (CNS) controls most functions of the body and mind. It consists of two parts: the brain and the spinal cord. The brain is the center of our thoughts, the interpreter of our external environment, and the origin of control over body movement. It interprets information from our special senses, as well as from internal organs Meninges: The coverings of brain and spinal cord are called meninge. There are 3 layers surrounding the brain and spinal cord. Dura (outer layer) Arachnoid (middle layer) Pia matter (inner layer) Dura mater: The tough outer layer is called the dura mater. protect the central nervous system. Arachnoid: The middle layer is the arachnoid, It contains cerebrospinal fluid, which acts to cushion the brain Pia matter: the innermost layer of the meninges, the pia mater closely covers the brain. Brain: Introduction: The brain is a complex organ that controls thought, memory, emotion, touch, motor skills, vision, breathing, temperature, hunger and every process that regulates our body. the brain and spinal cord Together make up the central nervous system, or CNS The brain receives information through our five senses: sight, smell, touch, taste, and hearing - often many at one time Diagram: Structure: The brain is composed of the cerebrum, cerebellum, and brainstem Cerebrum (telencephalon or endbrain): is the largest part of the brain and is composed of right and left hemispheres. It performs higher functions like interpreting touch, vision and hearing, as well as speech, reasoning, emotions, learning, and fine control of movement. Cerebellum (little brain): is located under the cerebrum. Its function is to coordinate muscle movements, maintain posture, and balance. Brainstem: consist midbrain, the pons, and the medulla oblongata acts as a relay center connecting the cerebrum and cerebellum to the spinal cord. Functions such as breathing, heart rate, body temperature, wake and sleep cycles, digestion, sneezing, coughing, vomiting, and swallowing. Lobes of the brain:  Each hemisphere has 4 lobes: Frontal lobe Temporal lobe Parietal lobe Occipital lobe Each lobe may be divided, once again, into areas that serve very specific functions The cerebral cortex has many folds, called the gyrus (plural: "gyri") and its trough is called a sulcus (plural: sulci) Deep structure of Brain: Hypothalamus: is located in the floor of the third ventricle and

1. By:
M. Thiru murugan
The Nervous System

2. Unit – 11:
a)Types of nerves- structure and functions
b)Brain and cranial nerves.
c)Spinal cord and motor and sensory pathways of the
spinal cord, autonomic nervous system.

3. Nervous system:
•Nervous system is one of vital system in our body which
control and coordinate all the functions of body parts.
Classification:
1. Central nervous system (CNS)
2. Peripheral nervous system (PNS)
1. Central nervous system (CNS): brain and spinal cord
2. Peripheral nervous system (PNS): Somatic nervous System
& Autonomic nervous system (ANS)

4. 1. Somatic
Nervous
System
Sym
NS
Motor
Nerves
2. Autonomic
Nervous
System
Sensory
Nerves
Spinal
Cord
Brain
2. Peripheral
nervous system
1. Central
Nervous System
Nervous System
Para
Sym
NS
Body to brain Brain to
Body Muscle
3. Enteric
nervous
System
(GIT)
Stimulate
the Body
Functions
Controls
Bodily
Functions

5. Central Nervous System (CNS):
• The central nervous system (CNS)
controls most functions of the body and
mind.
• It consists of two parts: the brain and
the spinal cord.
• The brain is the center of our thoughts,
the interpreter of our external
environment, and the origin of control
over body movement.
• It interprets information from our special
senses, as well as from internal organs

6. Meninges:
• The coverings of brain and spinal cord are called
meninge.
• There are 3 layers surrounding the brain and spinal
cord.
1. Dura (outer layer)
2. Arachnoid (middle layer)
3. Pia matter (inner layer)
• Dura mater: The tough outer layer is called the dura
mater. protect the central nervous system.
• Arachnoid: The middle layer is the arachnoid, It
contains cerebrospinal fluid, which acts to cushion the
brain
• Pia matter: the innermost layer of the meninges, the pia
mater closely covers the brain.

7. Brain:
Introduction:
• The brain is a complex organ that controls thought, memory, emotion,
touch, motor skills, vision, breathing, temperature, hunger and every
process that regulates our body.
• the brain and spinal cord Together make up the central nervous system, or
CNS
• The brain receives information through our five senses: sight, smell, touch,
taste, and hearing - often many at one time
Diagram:
Structure:
• The brain is composed of the cerebrum, cerebellum, and brainstem

8. Diagram of Brain:

9. • Cerebrum (telencephalon or endbrain): is the
largest part of the brain and is composed of
right and left hemispheres. It performs higher
functions like interpreting touch, vision and
hearing, as well as speech, reasoning, emotions,
learning, and fine control of movement.
• Cerebellum (little brain): is located under the
cerebrum. Its function is to coordinate muscle
movements, maintain posture, and balance.
• Brainstem: consist midbrain, the pons, and the
medulla oblongata acts as a relay center
connecting the cerebrum and cerebellum to the
spinal cord.
• Functions such as breathing, heart rate, body
temperature, wake and sleep cycles, digestion,
sneezing, coughing, vomiting, and swallowing.
Brainstem

10. Lobes of the brain:
• Each hemisphere has 4 lobes:
• Frontal lobe
• Temporal lobe
• Parietal lobe
• Occipital lobe
• Each lobe may be divided, once again,
into areas that serve very specific
functions
• The cerebral cortex has many folds,
called the gyrus (plural: "gyri") and
its trough is called a sulcus (plural:
sulci)

11. Deep structure of Brain:
• Hypothalamus: is located in the floor of the third ventricle and is the master control of
the autonomic system. It plays a role in controlling behaviors such as hunger, thirst,
sleep, and sexual response. It also regulates body temperature, blood pressure,
emotions, and secretion of hormones.
• Pituitary gland: The pituitary gland is connected to the hypothalamus of the brain by
the pituitary stalk. Known as the “master gland,” it controls other endocrine glands in
the body.
• Pineal gland: is located behind the third ventricle. It helps regulate the body’s internal
clock and circadian rhythms by secreting melatonin.
• Thalamus: serves as a relay station for almost all information that comes and goes to
the cortex. It plays a role in pain sensation, attention, alertness and memory.
• Basal ganglia: This work with the cerebellum to coordinate fine motions, such as
fingertip movements.

13. Ventricles of the brain and
cerebrospinal fluid(CSF):
• The brain has hollow fluid-filled cavities
called ventricles.
• Inside the ventricles is a ribbon-like
structure called the choroid plexus that
produces clear colorless cerebrospinal fluid
(CSF).
• CSF flows within and around the brain and
spinal cord to help cushion it from injury.
• There are 4 ventricles: 2 lateral ventricles,
third ventricle & fourth ventricle

14. Functions of brain:
•Frontal lobe: Personality, behavior, emotions, Judgment,
planning, problem solving, Speech: speaking and writing
(Broca’s area), Body movement (motor strip), Intelligence,
concentration & self awareness
•Parietal lobe: Interprets language, words, Sense of touch,
pain, temperature Interprets signals from vision, hearing,
motor, sensory, memory, Spatial and visual perception
•Occipital lobe: Interprets vision (color, light, movement)
•Temporal lobe: Understanding language (Wernicke’s area),
Memory, Hearing, Sequencing and organization

15. Neuron:
• Definition:
• The basic structural and functional unit of nervous system or brain is
called the Neuron.
Parts or structure:
• A neuron has three main parts:
1. Cell body
2. Dendrites
3. Axon
Classification of neuron:
1. Functional Classification
2. Structural Classification

16. Classification of neuron
• Functional Classification:
1. Sensory Neurons ( cells to brain)
2. Motor Neurons (brain to cells)
3. Interneurons (connects to other
interneuron)
• Structural Classification:
1. Unipolar Neurons
2. Bipolar Neurons
3. Multipolar Neurons

17. Diagram of Neuron:

18. Structure of Neuron:
• Also known as a soma, Neurons consist of a main part called the CELL
BODY, which contains the nucleus and various organelles. maintains the
neuron’s structure, and provides energy
• A DENDRITE (tree branch) is where a neuron receives input from other
cells. Like antennae, dendrites receive and process signals from the axons
of other neurons. Neurons can have more than one set of dendrites, known
as dendritic trees.
• An AXON is a long, tail-like structure which joins the cell body at a
specialized junction. Many axons are covered with a fatty substance
called myelin. Myelin helps axons to conduct an electrical signal.
Neurons generally have one main axon.

19. Functions of neuron:
• The main function of the neurons is to pass the receiving
information and send appropriate signals to the rest parts of
the body. The signals received are in the form of electrical
signals.
Glia cells: or Neuroglial cells:
• Glia (Greek word meaning glue) are the cells of the brain that
provide neurons with nourishment, protection, and
structural support. Ex - astrocyte, oligodendrocyte, and
microglial cell

20. CSF:
• Cerebrospinal fluid (CSF) is a clear,
colorless fluid found within the tissue
that surrounds the brain and spinal cord
Secretion:
• choroid plexus secrete cerebrospinal
fluid (CSF) and circulate in the
ventricles of brain
Function:
• Protection of brain and spinal cord
• Supply nutrient
• waste removal from brain.

21. Cranial nerves
Definition:
• The cranial nerves are a set of twelve nerves that
originate in the brain. Each has a different
function for sense or movement
• Each nerve has a name that reflects its function
and a number according to its location in the brain
• The general functions of the cranial nerves are
sensory, motor, or both:
• Sensory cranial nerves help a person to see,
smell, and hear.
• Motor cranial nerves help control muscle
movements in the head and neck.
I. Olfactory nerve
II. Optic nerve
III. Oculomotor nerve
IV. Trochlear nerve
V. Trigeminal nerve
VI. Abducens nerve
VII.Facial nerve
VIII.Vestibulocochlear
IX. Glossopharyngeal
X. Vagus nerve
XI. Accessory nerve
XII.Hypoglossal nerve

23. Cranial nerves &
Functions

24. Spinal cord:
• The spinal cord is a long, thin,
tubular structure made up of nervous
tissue, which extends from
the medulla oblongata in
the brainstem to the lumbar region of
the vertebral column
• It is about 45 cm long in men and about
43 cm in women
• Which contains CSF fluid.
• The brain and spinal cord together
make up the central nervous
system (CNS).

25. Structure:
• The spinal cord is divided into four different regions: the
cervical, thoracic, lumbar and sacral regions
• There are 31 segments, 31 pairs of nerves, These nerves
are divided into 8 cervical, 12 thoracic, 5 lumbar, 5
sacral, and 1 coccygeal nerve
• The cord is covered by meninges - Dura, Arachnoid
and Pia
• The collection of nerves at the end of the spinal cord is
known as the cauda equina
• The filum terminale is the nonfunctional continuation of
the end of the spinal cord
• Functions primarily in the transmission of nerve
signals from the motor cortex to the body, and from
the afferent fibers of the sensory neurons to the sensory
cortex.

26. Peripheral nervous system:
• the PNS consists of the nerves and ganglia outside the brain and spinal cord.
• The main function of the PNS is to connect the CNS to the limbs and organs,
essentially serving as a connection between the brain and spinal cord and the
rest of the body.
• It consist of Somatic Nervous System and Autonomic Nervous System
• The somatic nervous system (SNS), or voluntary nervous system is the part
of the peripheral nervous system associated with the voluntary control of body
movements via skeletal muscles.
• The somatic nervous system consists of sensory nerves carrying the sensation
from the body to the central nervous system (CNS).
• The other nerves are motor nerves carrying the commands from the CNS to
stimulate muscle contraction.

27. Autonomic nervous system:
• The autonomic nervous system is a involuntary control system
• Autonomic functions include control of respiration, cardiac regulation (the
cardiac control center), vasomotor activity (the vasomotor center), and
certain reflex actions such as coughing, sneezing, swallowing and vomiting.
• Parts: Three branches: sympathetic, parasympathetic nervous system and
the enteric nervous system.
• Sympathetic nervous system: primary process is to stimulate the body
functions. Ex - increase heart beat
• Parasympathetic nervous system: controls bodily functions when a person is
at rest. Ex - slows heart beat
• Enteric nervous system: Control the activity of intestine and GIT