dr. jitendra patel (mbbs, md) · dr. jitendra patel (mbbs, md) medical educator & researcher...
TRANSCRIPT
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DR. JITENDRA PATEL (MBBS, MD)
Medical Educator & Researcher
Associate Professor, Department of Physiology
Email: [email protected] 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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