Functional Organization of Nervous System - functions of central nervous system, spinal cord ( cross section) , cellular component of nervous system Physiology MBBS STUDENTS

1. Functional Organization
Of Nervous System
DR.ANITA CHOUDHARY
Prof. & Head
PHYSIOLOGY
R.D.Gardi Medical College
,Ujjain (MP)

2. NERVOUS SYSTEM
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2 SYSTEM
 System of COMMUNICATION- allows individual to
interact with external environment
 System of INTEGRATION – coordinate functions of
internal organs

3. Scientist contributed
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 Camillo golgi
 Santiago Ramon Cajal

4. Division of Nervous System
3 division
 Central nervous system (CNS)
 Peripheral Nervous System (PNS)
 Autonomic nervous system (ANS)
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5. CNS
 Part Of Nervous System Occupies The
Central Axis Of Body- Brain & Spinal Cord
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6. BRAIN
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 Weight …1.5kg(3% of total body weight)
 All structures are present inside the bony skull
 3 parts: fore brain
Mid brain
Hind brain
 4 interconnected cavities- cerebral ventricles

7. Brain is divided in 3 parts
 Fore Brain
 Mid Brain
 Hind Brain
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8. Telencephalon
 2 Cerebral hemisphere (
or cerebrum)
 Connected by bundle of nerve
fibers- commissures
 Cortex of each hemisphere is divided
into 4 lobes
Frontal , Parietal
Occipital , Temporal
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9. Cerebral cortex
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 Area of grey matter 3mm in thickness
 Have many folds – increase area for cortical
neurons

10. DIENCEPHALON
 Upper 2/3rd - Thalamus
 Lower 1/3rd -Hypothalamus
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11. FORE BRAIN-
Functions
 Telencephalon – 2 cerebral hemisphere
Perception of sensation , cognition ,learning
& memory , planning & programming of
responses
 Diencephalon – Thalamus &
Hypothalamus
Relay information to cortex and control
autonomic & endocrinal function4/11/2020
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12. Function of fore brain:
Involved in processing
complex information.
The midbrain and hindbrain are
similar with other animals, hence the
term Brain Stem
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13. MID BRAIN
Aqueduct of sylvius
divide into 2 parts
 Ventral part –
cerebral puduncle-
tegmentum,
substantia Nigra &
basis peduncle
 Dorsal part
(tectum) - colliculi
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14. Midbrain
 It is composed of two (2)
systems 1. The reticular
formation
2. Cluster of neurons having
dopamine, serotonin and
norepinephrine receptors
.
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15. Function of Mid brain:
 The reticular formation is involved with
stereotypical patterns of behavior such as
walking, sleeping, and other reflexes.
 The Midbrain serves to relay
information between the hindbrain and
the forebrain, particularly information
coming from the eyes and the ears.
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16. HIND
BRAIN(Rhobencephalon)
 The Hindbrain is located at the rear of the
skull and is the lowest portion of the brain.
 Include the Medulla, The Cerebellum And
The Pons.
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17. HIND
BRAIN(Rhombocephalon)
 Metencephalon –
Pons &
cerebellum)
 Myelencephalon -
Medulla oblongata
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18. Medulla
These where the spinal cord enters the
skull.
It is responsible for-
 controlling breathing
 regulating reflexes
 and maintaining an upright posture of the
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19. CEREBELLUM
 The cerebellum are two (2) rounded
structures located besides the medulla.
 It is responsible for coordinating motor
activity (movements of the body)
Extensive damage of the cerebellum can cause
failure to even stand up
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20. PONS
 Serves as the bridge towards the
midbrain.
 It is a cluster of neuronal fibers
surrounding the reticular formation
Responsible for monitoring sleep and
arousal by coordinating with the
autonomic nervous system.
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21. BRAIN STEM
 Mid brain ,Pons and Medulla together form brain
stem
 Cranial nerves situated in brain stem
Function of brain stem –control
 Cardio vascular function
 Respiratory function
 Motor activities
 Sleep wakefullness cycle
 Visceral function
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22. SPINAL CORD
 Length -45-50 cm
 Diameter – 2cm
 Shape – cylindrical
 Position – outside the skull base at foramen
magnum
 Terminate – 1st lumber vertebra
 Below that- cauda equina( lumber and sacral
roots)
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23. C.S of Spinal cord
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24.  Prominent anterior median fissure
 Less prominent posterior median fissure
 Between this is central cannal
 Grey matter – H-shaped
 Doral ( posterior) horn – long & narrow
 Ventral ( anterior) horn – thick & broad
 Horizontal septum of H- grey commissure
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25. Ventral or Anterior horn
 Contains cell bodies of alpha , gamma &
Renshaw motor neurons
 Axons of alpha & gamma motor neurons
pass – anterior roots
 These are pure motor nerves
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26. Doral or posterior horn
 Receives fibers of posterior roots
 Purely sensory in function
 Cell bodies lies in posterior root
ganglion ( swelling of posterior root)
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27. Intermediolateral horn
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 Present between ventral & dorsal horn
 Contain cell bodies of autonomic neurons
( sympathetic division)
 Extend only fro T1 toL2 segment of spinal
cord

28. White matter
 Surrounding the grey
matter
Three white coloumns
 Anterior white coloumn-
between ant median
fissure & anterior roots
 Lateral white coloumn –
between anterior &
posterior roots
 Dorsal white coloumn-
between posterior root &
posterior median fissure
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29. Function of the Nervous
System
 Communication between body parts &
integration of systemic function
 Appropriate regulation of body functions
 Coordinated interaction of the body with the
environment
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30. Basic design of Nervous
System
 Basic Functional unit – Neuron
 Sensory part of nervous system- Receptors
 Motor part of Nervous System- effectors
 Processing of information – Integrative
function
 Storage of information – Memory
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31. MAJOR PROCESS …
Recognition of stimulus & Transmission of
information in form of nerve signal to CNS
Processing of information in CNS
Generation of appropriate command signal in CNS
Specific response
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33. 1. Neuron
 CNS contain more than 100 billion neurons
 Incoming signal enter neuron through synaptic
connections
 Out put signals travel through Axon
 Signal passes only in forward direction from
axon of preceding neuron to dendrite on cell
membrane of subsequent neuron
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34. NEURON …SHOWING
IMPORTANT FUNCTIONAL PART
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35. 2 .SENSORY PART OF NS
 Nervous system uses its millions receptors to
monitor changes occurring inside and outside
body.
 Those changes are called stimuli
 and gathered information is called Sensory
input
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36. Information enter CNS through
peripheral nerves and conducted to
 Spinal cord at all levels
 Reticular sub of medulla & Pons
 Cerebellum
 Thalamus
 Area of Cerebral cortex
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37. 3. INTEGRATIVE FUNCTION
 The nervous system process and
interprets the sensory input and
make decision about what should be
done at each moment …a process
called integration
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38. ….Processing of information &
generation of command signal (
Synapse)
 Information relayed in Thalamus
 Processed in sensory cortex
 Than transfer to other signals
 Planning & programming mechanism
 Generation of appropriate command
 Transmission of command signal to effector
organs
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39. 3. MOTOR PART OF NERVOUS
SYSTEM
 The nervous system then sends
information to muscles, glands and
organs so they can respond
correctly, such as muscular
contraction or glandular secretion
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40. Motor function can be controlled at
many levels of nervous system
 Spinal cord
 Medulla & Pons
 Basal ganglia
 Cerebellum
 Motor cortex
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41. CELLULAR COMPONENT OF
CNS
2 TYPES OF CELLS
 Glial cells ( Neuroglia)
 Neurons
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42. GLIAL CELLS
 10 – 30 Times more than Neurons
 Support and protect the neurons
 Play metabolic role & provide nutrition to
neuron
 Maintain homeostasis of fluids(matrix) in which
neuron are placed
 Regulate blood blow through brain4/11/2020
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43. Glial cells ….
 Source of ions
 Insulate axons & synapses and electrically
isolate them from one another
 Phagocytose neural debris
 Do not conduct AP
 Do not form functional synapse
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44. Types of Glial cells
4 types
 Astrocytes ( Astroglia)
 Oligodendrocytes ( oligodendroglia)
 Ependymal cells
 Microglia
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45. Astrocytes
 Star shaped
 Found in brain &
spinal cord
 Process of
astrocytes
surrounds the
neurons & their
axons
 Terminate on
blood vessel
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46. Oligodendrocytes
 Found close to myelinated axons
 Wrap axons many times to form sheath that
insulate axons
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47. Ependymal cells
 These cells line the CSF-filled ventricles in
the brain and the central canal of the spinal
cord.
 These are nervous tissue cells with a ciliated
simple columnar form much like that of some
mucosal epithelial cells
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48. Microglial cells
 These cells mediate immune responses in the
central nervous system by acting as
macrophages, clearing cellular debris and
dead neurons from nervous tissue through the
process of phagocytosis (cell eating).
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50. THANK YOU
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51. PERIPHERAL NERVOUS
SYSTEM
 Part of Nervous system outside the CNS
 Divided into somatic & Autonomic Nervous
system & Enteric nervous system
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52. Somatic Nervous system
 Made up of all nerve fibers going from CNS to
skeletal muscle cells
 Consist of Spinal nerves & Cranial nerves
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53. SPINAL NERVES
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 31 Pairs of spinal nerves
 Each pair is attached to the spinal cord by 2 roots(
dorsal & ventral root)
8 pairs of cervical nerves
12 pairs of thoracic nerves
5 pair of Lumber nerves
5 pairs of Sacral nerves
1 pair of coccygeal nerve

54. Cranial nerves
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 12 pair
 Cell bodies in brain
 some are …afferent
 some are … efferent
 some are … mixed

55. AUTONOMIC NERVOUS
SYSTEM
 The innervations of all tissue other than
skeletal muscle is by ANS
Sympathetic Division
 Consist of thoracic & lumber ganglion-
(thoraco-lumber division)
Parasympathetic Division
 Consist of cranial ganglia ( III, VII, IX,& X
crainal nerves) & sacral ganglia ( 2nd 3rd & 4th
sacral segment) called cranio-sacral division
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56. C. ENTERIC NERVOUS
SYSTEM
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 It is extensive network of neurons located in
the walls of organs of the GIT

57. STUDENT MUST KNOW
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1. Division of nervous system and outline functions
of each division
2. Name different parts of brain and their functions
3. Name the cell type of CNS
4. List the type of Glial cell & give their function
5. Draw the cross section of spinal cord & label the
prominent structures
6. Describe the organization of nervous system