The human nervous system coordinates the activities of the body and allows it to respond quickly to external stimuli. It is composed of neurons, which are specialized cells that transmit signals. Neurons have an axon, which transmits signals, dendrites, which receive signals, and a cell body. The central nervous system, made up of the brain and spinal cord, processes all information and is protected by bone and fluid. Reflexes are automatic responses that travel through a reflex arc in the spinal cord without involving the brain.

2. • It is system that helps all other
system of our body to work.
• Its function is to coordinate the
activities of our body.
• The human nervous system
receives information from the
surrounding , processes it ,
interprets it and respond quickly.

4. • OUR NERVOUS SYSTEM IS MADE UP OF
SPECIAL CELLS CALLED NEURONS
• THE CELL BODY OF A NEURON IS LIKE A
TYPICAL ANIMAL CELL WHICH CONTAIN
CYTOPLASM AND NUCLEUS

5. THE NEURONS HAVE 3 COMPONENTS :
AXON : It is the longest fibre on the cell body of
neuron. it has an insulating and protective sheath of
myelin around it.
DENDRITES : It picks up the nerve impulse
(message) from receptors and the passes to cell
body and then to axon.

6. CENTRAL
NERVOUS
SYSTEM
PERIPHERAL
NERVOUS
SYSTEM
AUTONOMIC
NERVOUS
SYSTEM
VOLUNTARY
NERVOUS
SYSTEM

7. • The human central nervous system is made up of;
• 1. Brain
• 2. Spinal cord
• The complete central nervous system consist of up
to 100 billions inter-neurons
• Brain and spinal cord are protected in protected
bony armour, the skull and the vertebral column.
• Both the spinal cord and brain are covered in three
continuous sheets of connective tissue called
meninges.
• A plasma like fluid, the cerebrospinal fluid (CSF)
bathing the neurons of CNS is yet another
protection to CNS.

9. • Brain is the highest coordinating centre in the body
• Located inside the skull (at the top of the spinal chord)
• protected by a bony box in the skull-Cranium
• Surrounded by 3 membranes-Meninges
• The space between the membranes id filled with a
cerebro spinal fluid, which protects the brain from
mechanical shocks

10. ►The brain of all vertebrates develops from
three swellings at the anterior end of the
neural canal of the embryo.
►Human brain is divided into three parts;

13. • Reflex Action-This is a rapid, automatic
response to a stimulus which is not
under voluntary control of the brain. The
stimulus produces the same response
every time
• Sneezing and Blinking are two examples
of Reflexes.

14. • REFLEXES are very fast, and Most Reflexes
Never Reach the Brain.
• Sensory Neurons carry impulses from
RECEPTORS to the spinal cord.
• Motor Neurons carry impulses from the spinal
cord to the EFFECTORS.
• Within the spinal cord, motor and sensory
neurons are connected by INTERNEURONS.

16. • Reflex Arc- The pathway (or route)taken by nerve
impulses in a reflex action