anatomy of nervous system

1. NERVOUS SYSTEM
BY
SONI KUMARI SHAH

2. Nervous System
Chief controlling and conducting system of our body which regulates all body
activities based on sensitivity, conductivity and responsiveness
Classification Of Nervous System
Nervous system
Peripheral Nervous SystemCentral Nervous System
Spinal CordBrain AfferentEfferent
Autonomic Nervous
System
Somatic Nervous
System
Sympathetic Parasympathetic

3. Functions Of Nervous System
Controls, regulates and co-ordinates body activities.
Respond the stimuli within the body and in the external environment.
Transmit nerve impulses to and away from the CNS.
Interprets nerve impulses arriving in the cerebral cortex of the brain.
Assimilates experiences as required in memory, learning and
intelligence.
Initiates glandular secretion and muscular contraction.

4. Cell Types Of Nervous System:
1. Excitable Cells:
Neurons Or Nerve Cells
2. Non-excitable Cells:
Neuroglial Cells
A. Ependymal Cells
B. Capsular Or Satellite Cells
C. Schwann Cells
D. Astrocytes
E. Oligodendrocytes
F. Microglia

5. Neuron
Structural and Functional unit of nervous system.
It receives, integrates, interpret and transmit the nerve impulse from one part
of the body to another.
 Specialized for sensitivity and conductivity
Shows dynamic polarity in its processes

6. Structure of neuron
Cell body/perikaryon
Cytoplasm contains all cell organelles of a typical cell.
It also contains Nissl substance, Neurofibrils and pigment granules.
Processes/neurites
Dendrites- short processes which carrries nerve impulses towards the cell.
Axon- single long process which carries impulse away from the cell.

7. Classification of Neurons
According to number of their processes:
1. Unipolar Neuron- has only one neurite; either axon or dendrite
eg. mesencephalic nucleus
2. Pseudo unipolar Neuron- only one process arise from the cell but shortly after it
bifurcates into 2 processes; one axon and one dendrite
eg. sensory ganglia or spiral ganglia
3. Bipolar Neuron- has 2 processes; one axon and one dendrite
eg. spiral & vestibular ganglia
4. Multipolar Neuron- has many processes; one axon and numerous dendrites
eg. cerebrum & cerebellum
According to size:
1. Macroneuron: >7µm
2. Microneuron: <7µm

8. According to Length of Axon:
1. Golgi Type I: long axons
eg. pyramidal cells of cerebral cortex, purkinje cells of cerebellum and
anterior horn of spinal cord
2. Golgi Type II: short axons
eg. cerebral cortex, cerebellar cortex
3. Amacrine Neuron: without axon
eg. retina of eyeball
According to Shape:
1. Stellate
2. Basket
3. Fusiform
4. Pyramidal

9. According to Function:
1. Sensory Neurons- carries sensory information from peripheral receptors to CNS
a. Primary
- dorsal root ganglion of spinal nerves
b. Secondary
- grey matter of spinal cord, brainstem
c. Tertiary
- thalamus
2. Motor Neurons-carries motor information from CNS to effector organs
Motor Neuron Of Somatic Nervous System
a. Upper motor neurons
- motor area of brain
b. Lower motor neurons
- cranial nerve nuclei, anterior horn of spinal cord
Motor Neurons Of Autonomic Nervous System
a. Parasympathetic
b. Sympathetic
3. Interneurons- associates or connects sensory neurons with motor neurons

10. Functional Neurons cont……
Sensory neurons(afferent)
Carry information to CNS
Detect pressure heat or light
Interneurons
Connect motor and sensory neurons in CNS(most numerous type of neuron)
Carries information from spinal cord to brain]
Motor neurons(efferent)
Carry information to the muscles and glands
Important part of PNS

11. Supporting cells:
1. CNS supporting cells:
a. Astrocytes: star shaped; assists in exchange
between blood capillaries and neurons;
help to form BBB
b. Oligodendrocytes: forms myelin sheath
around axon in CNS
c. Ependymal cells: covers choroid plexus;
lines ventricles of brain; produce CSF;
assist in circulation of CSF
d. Microglia: behave like macrophages; phagocytic Ependymal cell

12. 2. PNS supporting cells:
a. Capsular or Satellite cells:
surrounds neuron cell body in ganglion;
provide structural support;
regulates exchange of materials between
neuron cell body and interstitial fluid.
b. Schwann cells:
forms myelin sheath around axon in PNS

13. Usually axon carries nerve impulse
1. Towards the cell body
2. Towards the dendrite
3. Away from cell body
4. All of the above
Blood Brain Barrier is made up of
1. Oligodendrocytes
2. Astrocytes
3. Schwann cell
4. Meninges
The physiological unit of nervous system is
1. Neuron
2. Neuroglia
3. Astrocytes
4. Nerve impulse