Central nervous system- An introduction

1. NERVOUS SYSTEM-I
Dr Vishwajit Deshmukh
MBBS, M.D. Anatomy

2. Terms commonly used in nervous system
• Nerve fiber Axon
• Nerve Bundle of nerve fibers outside CNS
• Tract Bundle of nerve fibers inside CNS
• Ganglion Nerve cell bodies outside CNS
• Nucleus Nerve cell bodies inside CNS
• Sensory neuron To the CNS
• Motor Neuron From the CNS
• Nerve Plexus Network of intercalated nerves
Terminologies

5. DEVELOPMENT OF
NERVOUS SYSTEM
 Study of development helps to understand it’s
complex organization and the occurrence of
congenital anomalies
 The whole of the nervous system develops from
the ectoderm except it’s blood vessels and some
glial cells
 The specific cell population giving rise to the to
entire nervous system is termed as
neuroectoderm

6. Neurulation
Anterior
and
posterior

11. Parts of
Nervous system

14. THE NEURONS ARE THE
STRUCTURAL AND
FUNCTIONAL UNITS OF THE
NERVOUS SYSTEM
 They are specialized for
reception, integration,
interpretation and onwards
transmission of the
information
 They conduct the nerve
impulses across the long
distances
 1012 number of neurons

15. STRUCTURE OF NEURON

17. Neurons are classified based on number of processes arising from the soma

18. Relative length of the axon and dendrites

20. ASTROCYTES AND
FUNCTIONS
Astrocytes are the largest of the neuroglial
cells. They form a network of cells within
the CNS and communicate with neurons to
support and modulate many of their
activities.
Some astrocytes span the entire thickness
of the brain, providing a scaffold for
migrating neurons during brain
development. Other astrocytes stretch their
processes from blood vessels to neurons.
The ends of the processes expand, forming
end feet that cover large areas of the outer
surface of the vessel or axolemma.

21. BBB

22. Fibrous astrocytes are more
common in the inner core of the brain
called white matter. These astrocytes
have fewer processes, and they are
relatively straight
Protoplasmic astrocytes are
more prevalent in the outermost
covering of brain called gray matter.
These astrocytes have numerous,
short, branching cytoplasmic
processes

24. Oligodendrocytes and Schwann Cells

26. Microglial cells
Smallest glial cells
Derived form the
phagocytic WBC
Derived from mesoderm
They enlarges and becomes
phagocytic in area of
inflammation

28. Other glial cells in Nervous system

29. • The point at which the nerve impulse passes from one neuron
to another is called synapse
• The nerve impulse passes in one direction
• Slight delay and get fatigue

31. Thanks
VDsnaps