2. The brain, spinal cord and the nerves are the components of the
human nervous system.
Human nervous
system
can be
divided into
Central Peripheral Autonomic
Nervous System Nervous Nervous
System System
CNS PNS ANS
3. The CNS is a delicate structure
composed of BRAIN and SPINAL
CORD.
Protective membranes called
MENINGES are present in the space
between soft CNS and the bone.
CRANIUM or the SKULL is a bony structure
which protects the brain.
VERTEBRAL COLUMN or the BACK
BONE protects the spinal cord.
4. Different parts of brain Spinal cord
Ventricles, central canal and spaces
between meninges are filled with
CEREBROSPINAL FLUID(CSF), keeping
CNS nourished.
It protecting CNS by absorbing
mechanical shock.
5. NERVES
All the nerves are included in the peripheral system.
Forms a network and spreads throughout the body.
Instrumental in connecting all parts of the body in CNS.
On the basis of function, they are categorized as: afferent
and efferent nerves.
Afferent Nerves carry impulse: Sensory organs Brain.
Efferent Nerves carry impulses: Brain Sensory organs.
6. NEURONS
Direction of impulse
Nucleus
Dendrite
s
Nerves are
composed of
specialized cells-
neurons capable of Cyton
creating & (cell body)
transmitting
electronic impulses
& neuroglia-
supportive cells
assisting neurons in Axon
their function.
To next neuron
Axon ending
7. Neuron
In accordance to their functions, NEURONS are classified into:
Neurons
Sensory Motor Association
neurons neurons neurons
Conducts impulses from Conducts impulses from Brain Perform integrative functions of
sense organs to Brain &spinal cord to effector organs, nervous system.
&Spinal cord. i.e. muscles and glands
8. Peripheral Nervous System.(PNS)
Voluntary actions involve our muscles. Brain sends message to the muscles
& muscles act accordingly. This communication between the CNS and
other parts of body is brought about by the PNS.
Composed of CRANIAL NERVES arising from brain & SPINAL NERVES
arising from spinal cord. or Medulla oblongata
Cerebrum or forebrain is
main thinking part of brain.
Involuntary actions are
controlled by mid-brain and
hind brain(medulla
oblongata).
Cerebrum has regions
which receive the sensory
impulses from various
receptors.
9. AUTONOMIC NERVOUS
SYSTEM
It is called as ANS.
It comprises of all nerve present in the involuntary organs like heart , stomach ,
lungs , etc.
Conducts impulses from CNS to cardiac muscles, smooth muscles and glands.
10. Left hemisphere of brain has 186 million more neurons than the right
hemisphere.
750-1000 ml of blood flows through brain every minute.
Brain can stay alive 4-6 min without oxygen.
Albert Einstein's brain weighed 1230 gm., less than avg., weight of
human brain-1300 to 1400 gm.
