DR. JITENDRA PATEL (MBBS, MD) · DR. JITENDRA PATEL (MBBS, MD) Medical Educator & Researcher...

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DR. JITENDRA PATEL (MBBS, MD)

Medical Educator & Researcher

Associate Professor, Department of Physiology

Email: dr.jrpatel84@gmail.com Web: www.esphys.weebly.com2

Competency

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No. PY 10.1 (CNS Physiology)

CompetencyDescribe and discuss the organization of nervous system

D/L/Core K/KH/Y

AM Written/Viva voce

Integration Yes (Human Anatomy)

Imp. Concept Neurons

Phy. Trivia Functional aspects

OUTLINE

Basic introduction

Division

Functions

Cellular component

Basic concept in CNS

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Comparison with computer

Central Nervous System (CNS)

Brain Spinal Cord

Peripheral Nervous System (PNS)

Cranial nervesPeripheral nerves

Divisions Of Nervous System

Fore brain Mid brain Hind brain

•The brain :

•Fore brain

•Telencephalon – Cerebral hemispheres

•Diencephalon – Thalamus, Hypothalamus

•Mid brain/Mesencephalon

•Tegmentum, substantia nigra, tectum (sup/inf colliculi)

•Hind brain/Rhombencephalon

•Pons, medulla, cerebellum

•Spinal cord

•Nuclei:

•Clusters of cell bodies in CNS

•Ganglia:

•Clusters of cell bodies in PNS

Spinal Cord Organization

To the brain

From the brain

lobe

Lateral View of The Brain

Medial View of The Brain

Functions Of Brain

• 100 billion multipolar neurons

• It is responsible for processing sensory information,

• Integrating information

• Initiating motor activities.

• Storing memory

• Reasoning

• Controlling visceral activities,

• Providing personality, generating emotions, behavior, judgment, language

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• Neurons

• Glial cells

• Astrocytes

• Oligodendrocytes

• Microglia

• Ependymal cells

Glial cells

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Glial cells

Glial cells of nervous system are called neuroglia.

Glial cells neither conduct action potential nor form

functional synapse with other cells.

Though glial cells generally provide support for

neurons, their functions are complex and not

completely understood.

Neuroglias are 10 – 30 times plentiful than neurons.

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Features Functions

star shapeSite;

Brain and Spinal cord

1. They provide themechanical matrix.2. They serve metabolic andnutritive functions forneurons.3. Synapses in CNS are usuallysurrounded by the processesof astrocytes. Thus, astrocyteselectrically insulatesynapses and separate themfrom one another.

1. Astrocytes

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Features Functions

Oligodendrocytes are found close to the

myelinatedaxons in the brain and

spinal cord.

1. They form the myelin sheath.This sheath not onlyinsulates axons from oneanother, but also limitscurrent flow across the axonmembrane. (Schwann cellsdo for peripheral nerves)

2. Because of this myelination,action potential is conductedin a saltatory fashion inmyelinated fibers

2. Oligodendrocytes

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Features Functions

Microglia are the smallest cells in the

central nervous system

1. They are the scavengercells in brain. If thenervous tissue is damagedor infected, these cellsenlarge and becomemononuclear phagocytesto eliminate debris andorganisms.

3. Microglia

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Features Functions

Ependymal cells line the surfaces of the brain’s

ventriclesand central canal of the

spinal cord

Their function is unclear

4. Ependymal cells

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Cell BodyDendrites

Axon

MyelinSheath

Dendrites of another neuron

Synapse

• According to arrangement of axon or process

Unipolar

Pseudounipolar

Bipolar

Multipolar

Types of neuron

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• According to the length of axon

Golgi type I

Golgi type II

Types of neuron cont…

• According to the function

Sensory

Motor

Types of neuron cont…

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• According to dendritic pattern

Pyramidal cells

Stellate cells

Types of neuron cont…

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M

M

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What Matter…!!!

White Matter Gray Matter

White in color due to myelin sheath

Generally responsible for carrying information

Gray/red in color due to the lack of myelin sheath.

Generally responsible for processing information. (Nerve impulses are generated here)

(W-M)

• Sensory

First order neuron

second order neuron

third order neuron

• Motor

UMN

LMN

Basic concept

• Generalized response - Sympathatic

• Localized response - Parasympathatic

Sympathatic Vs Parasympathatic

Above brain stem

Higher centre Vs lower centre

• Receptor

• Afferent

• Centre

• Efferent

• Effector organ

• Response

Reflex

• Consciousness

• Learning and memory

• Speech

• Emotions

• Behaviors

Higher functions

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