The nervous system consists of nerves that control and coordinate all body functions and systems. It has three primary functions - sensory input, information processing, and motor output. The basic functional unit of the nervous system is the neuron. There are three types of neurons - sensory, motor, and interneurons. The brain is the control center and is divided into regions including the cerebrum, brainstem, and cerebellum that control various functions like movement, senses, reasoning, and balance. The spinal cord relays messages between the brain and body and is divided into cervical, thoracic, lumbar, and sacral regions.

2. Nervous System
- body’s communication network that
consists of all nerves, controls and
coordinates all essential functions of the
body including all other body systems.

3. HOW THE
NERVOUS
SYSTEM
WORKS?

4. Three Primary Functions:
• Sensory Input- The ability of the nervous system to
sense changes in either the internal or external
environment.
• Integrative (information processing)- the ability of the
nervous system to analyze and interpret the sensory
information to allow for proper decision making,
producing the appropriate response.
• Motor output- The neuromuscular response to the
sensory information.

5. NEURON
-basic functional unit or cell of
nervous system

6. THREE TYPES OF NEURONS:
• Sensory neurons –
bring messages to CNS.
• Motor neurons - carry
messages from CNS.
• Interneurons –
between sensory &
motor neurons in the
CNS.

8. NERVOUS TISSUE two main cell types:
• neurons (nerve cells)
• neuroglia (glial cells)-
Glia, also called glial cells
or neuroglia, are non-
neuronal cells in the
central nervous system
(brain and spinal cord)
and the peripheral
nervous system that do
not produce electrical
impulses

9. Divisions of
Nervous System

10. THE BRAIN

11. Cerebrum
• The cerebrum (front of brain)
is composed of the right and
left hemispheres, which are
joined by the corpus
callosum. Functions of the
cerebrum include: initiation
of movement, coordination
of movement, temperature,
touch, vision, hearing,
judgment, reasoning,
problem solving, emotions,
and learning.

12. Brainstem
• The cerebellum (back of
brain) is located at the back
of the head. Its function is
to coordinate voluntary
muscle movements and to
maintain posture, balance,
and equilibrium.
Cerebellum

13. The Lobes of the Brain

14. CORTEX
• The surface of the cerebrum is called the cortex. The cortex contains 16 billion
neurons (the cerebellum has 70 billion = 86 billion total) that are arranged in
specific layers. The nerve cell bodies color the cortex grey-brown giving it its
name – gray matter. Beneath the cortex are long nerve fibers (axons) that
connect brain areas to each other — called white matter. The folding of the
cortex increases the brain’s surface area allowing more neurons to fit inside the
skull and enabling higher functions. Each fold is called a gyrus, and each groove
between folds is called a sulcus.

15. Deep Structures

16. Hypothalamus
• 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.

17. Pituitary Gland
• lies in a small pocket of bone
at the skull base called the
sella turcica. 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. It secretes hormones
that control sexual
development, promote bone
and muscle growth, and
respond to stress.
• is located behind the third
ventricle. It helps regulate
the body’s internal clock and
circadian rhythms by
secreting melatonin. It has
some role in sexual
development.
Pineal Gland

18. 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.

19. • includes the caudate,
putamen and globus
pallidus. These nuclei
work with the
cerebellum to
coordinate fine
motions, such as
fingertip movements.
• Is the center of our
emotions, learning, and
memory. Included in this
system are the cingulate
gyri, hypothalamus,
amygdala (emotional
reactions) and
hippocampus (memory).

20. THE SPINAL CORD
• The spinal cord is about 18 inches long and is the thickness of your thumb. It runs
from the brainstem to the 1st lumbar vertebra protected within the spinal canal.
The spinal cord serves as an information superhighway, relaying messages between
the brain and the body. The brain sends motor messages to the limbs and body
through the spinal cord allowing for movement. The limbs and body send sensory
messages to the brain through the spinal cord about what we feel and touch.
Sometimes the spinal cord can react without sending information to the brain

21. • The spinal cord is made of gray and white matter just like other parts of the
CNS. It shows four surfaces: anterior, posterior, and two lateral. They
feature fissures (anterior) and sulci (anterolateral, posterolateral, and
posterior). The gray matter is the butterfly-shaped central part of the spinal
cord and is comprised of neuronal cell bodies. It shows anterior, lateral, and
posterior horns. White matter surrounds the gray matter and is made of
axons. It contains pathways that connect the brain with the rest of the body.

22. • The spinal cord and spinal nerve roots are wrapped within three
layers called meninges. The outermost is the dura mater, underneath
it is the arachnoid mater, and the deepest is the pia mater. Dura
mater has two layers (periosteal and meningeal), between which is
the epidural space. Between the arachnoid and pia mater is the
subarachnoid space, it is filled with cerebrospinal fluid.

23. Spinal Cord Divided Into Four Regions:
• Cervical Segments (8)- Being the
anterior most segments of the
spinal cord that run across seven
cervical vertebrae, it is located
along the neck region
• Thoracic Segments (12)- vertebrae
in the thoracic region, they
constitute 12 pairs of thoracic
nerves each of which leaving the
vertebral column below the
associated vertebral division.

24. • Lumbar Segments (5)- It is one of the
parts of spinal cord that is protected by
five lumbar vertebrae; it gives rise to
five pairs of nervous extensions each
of which emerges below the
associated vertebra.
• Sacral Segments (5)-The same is the
case with this region, i.e. five sacral
nerve pairs leave your backbone just
beneath each bony segment and are
named as S1, S2, S3, S4 and S5.

25. • Coccygeal Segments (1)-The
lower most portion of the
neural tube that gives rise to
one pair of coccygeal nerves
and leaves the vertebrae
through sacral hiatus.
However, here you will find
that three segments of the
region fuse together to form a
single unit.