The nervous system consists of the brain, spinal cord, and a network of nerves that facilitate communication between the central nervous system and the body's organs and tissues. It is composed of two main types of cells: neurons and glial cells, and features structures such as the cerebrum, cerebellum, brainstem, and various glands that regulate bodily functions. Major components like the pituitary gland and hypothalamus play crucial roles in hormone secretion and the regulation of multiple physiological processes.

1. NERVOUSSYSTEM
The nervous system derives its name
from nerves, which are cylindrical
bundles of fibers
(the axons of neurons), that emanate
from the brain and spinal cord, and
branch repeatedly to innervate every
part of the body.
The system of nerves and nerve
centers in human, including the brain,
spinal cord, nerves, and ganglia.

2. NERVE:
A nerve is an enclosed, cable-like bundle of axons (the projections of
neurons) in the peripheral nervous system (PNS).
In the central nervous system, the same structures are known as tracts.
A nerve provides a structured pathway that supports the electrochemical
nerve impulses transmitted along each of the axons through synapse.
Nerves are the organs that make up the peripheral nervous system
(PNS).
Theyserveasinformation pipelinesthat allow thebrain andspinal cord
to communicate with other tissues and organs.

4. Structure:
 Inside the nerves, groups
called fascicles (fasciculi).
of neurons (nerve cells) are organized into bundles
 Surrounding and holding together each fascicle is the perineurium. This layer appears
concentrically laminated and is composed of flattened cells, basement membrane, and collagen
fibers.
 Inside the fasicles, each neurons and blood vessels are held in place by a loose connective
tissue referrred to as endoneurium.
 Epineurium, a layer of dense connective tissue, covers and holds together the outer surface of
nerves.
 Arteries and veins are located between the fascicles. Branches of these vessels enter the fascicles
and supply the neuronswith nutrientsand gases.
 Renaut body is the pink colour cellular structure that perform supportive and mechanical cushion
effect on neurons.

5. THE NERVOUS SYSTEM CONTAINS TWO MAIN TYPES OF CELLS:
NEURONS GLIAL CELLS

10. THE CENTRAL NERVOUS SYSTEM (CNS)
THE CNS IS MADE UP OF
 THE BRAIN
 SPINAL CORD
 BRAINSTEM and
 RETINA.

12. BRAIN OVERVIEW:
• The average adult human brain weighs about 3 pounds (1300
to 1400 grams). When we consider a newborn baby’s brain, it
weighs approximately three-quarters of a pound (350 to 400
grams).
• In terms of dimensions, the human brain measures about 5.5 x
6.5 x 3.6 inches (140 x 167 x 93 mm).
• It has 86 -100 billion neurons, enables memory, learning, and
adaptability.
• the brain is considered fully formed by the age of 25.
• It develops from back to front, with the prefrontal cortex
responsible for decision-making and reasoning.
• Interestingly, men tend to have slightly larger brains than
women, but specific brain regions differ between the sexes.

14. THE BRAIN
THE BRAIN
The human brain is probably the most complex structure.
It is the centre of control of all the body functions and senses.
The average weight of the human brain is around 1.5 kg.
The brain is composed of the
 CEREBRUM,
 CEREBELLUM,
 AND BRAINSTEM

16. CEREBRUM
CEREBRUM
It is the largest part of the brain and is composed
of right and left hemispheres.
The surface of the cerebrum is called the cortex.

18. CEREBRALHEMESPHERE
Right brain – left brain:
 The cerebrum is divided into two halves: the right and left hemispheres.
 They are joined by a bundle of fibers called the corpus callosum that transmits messages from one
side to the other.
 Each hemisphere controlsthe opposite side of the body.
 In general, the left hemisphere controls speech, comprehension, arithmetic, and writing.
 The right hemisphere controls creativity, spatial ability, artistic, and musical skills.

21. MAJOR DIVISION OF
BRAIN

24. GYRUSANDSULCUS
GYRUSAND SUL
CUS
cerebral cortex has a folded appearance with hills and
valleys.
The cortex has a folded appearance. A fold is called a
gyrus and the valley between is a sulcus.

25. A gyrus (plural: gyri) is a ridge on the surface of
the brain. Each ridge is surrounded by fissures
known as sulci (singular: sulcus).
Gyri are unique structures that have an
important evolutionary function; they increase
the surface area of the brain up to an impressive
2000 centimeters squared.

28. The cortex contains neurons cellbodies (grey matter), which are
interconnected to other brain areas by axons (white matter).
Grey matter is the “outer shell” of the brain and makes up most of the surface,
or cortex, as well as the cerebellum, cerebrum, and brain stem.
•Grey matter gets its name from the pinkish grey colour of the brain tissue in
these areas—which comes from a dense collection of somas, dendrites, and
non-myelinated axons.

29. • White matter is what lies beneath the grey
matter in the brain.
• White matter is mostly made up of axon
tracts which transmit electrical signals to
other neurons.
• It gets its name from the fatty tissue that
wraps around the axon called myelin.

30. LOBES OF THE BRAIN:
 LOBES OF THE BRAIN:
The cerebral hemispheres have distinct fissures, which divide the brain into
lobes.
 Each hemisphere has 4 lobes: frontal, temporal, parietal, and occipital .
 Each lobe may be divided, once again, into areas that serve very specific
functions.

37. DEEP STRUCTURES
1. Pituitary gland,
It also called as Hypophysis,it is a ductless gland of the
endocrine system.
Known as the “master gland,” it controls other endocrine
glands in the body.
The term hypophysis (from the Greek for “lying under”)—
refers to the gland's position on the under the brain.

39. •Lies in a small pocket of bone at the skull base
called the sella turcica.
most inferior portion
•The sella turcica's is known as
the hypophyseal fossa , contains the pituitary gland
(hypophysis).
It is connected with the hypothalamus of the
brain by the pituitary stalk.

41. HORMONES PITUITARY

42. 2. Pineal gland:
• It is located behind the third ventricle secreting
melatonin hormone.
•It has some role in sexual development. promote
bone and muscle growth, and respond to stress.

44. 3. Hypothalamus:
•It 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.

46. 4.Thalamus:
•It 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.
•It is divided into right and left thalamus

49. The hormones produced in the hypothalamus are
• Corticotrophin-releasing hormone,
• Dopamine,
• Growth hormone-releasing hormone,
• Somatostatin,
• Gonadotrophin-releasing hormone
• Thyrotrophin-releasing hormone.

50. 5. Basal ganglia:
•The basal ganglia (or basal nuclei) are a group of
subcortical nuclei.
provide a feedback mechanism
•The basal ganglia to the
cerebral cortex, modulating and refining cortical activation.
• These nuclei work with the cerebellum to coordinate
fine motions, such as fingertip movements.

52. 6. Limbic system:
It consists of the Amygdala,
Hippocampus, Thalamus, Hypothalamus, Basal Ganglia,
And Cingulate Gyrus.
The limbic system is a set of structures in the brain that deal with
emotions and memory.
It regulates autonomic or endocrine function in response to
emotional stimuli .