REGULATORS OF LIFE

Human nervous system

-By Gauri Chaudhari

10th B

Human nervous system

The brain, spinal cord and the nerves are the components of the human nervous system. Human nervous system

can be divided into

Central Nervous System

CNS

Peripheral Nervous System

PNS

Autonomic Nervous System

ANS

CENTRAL NERVOUS SYSTEM

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.

CAVITIES

Ventricles

Central Canal

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.

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.

NEURONS

Dendrites

Nucleus

Cyton(cell body)

Axon

Axon ending

Direction of impulse

To next neuron

Nerves are composed of specialized cells-neurons capable of creating & transmitting electronic impulses & neuroglia-supportive cells assisting neurons in their function.

NeuronIn accordance to their functions, NEURONS are classified into:

Neurons

Sensory neurons

Association neurons

Motor neurons

Conducts impulses from sense organs to Brain &Spinal cord.

Conducts impulses from Brain &spinal cord to effector organs, i.e. muscles and glands

Perform integrative functions of nervous system.

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.

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.

Interesting Facts……. 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.

THANK YOU!!!