1.dental lecture1 (introuduction)(1).pdf

7/30/2019 1.dental lecture1 (introuduction)(1).pdf

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Neurophysiology of the central

nervous system

Dr. Loai Alzghoul

[email protected]


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Organization of the nervous

system


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Organization of the nervous

system


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Levels of the CNS

1)Spinal cord

2)Brain stem and sub cortical

3)Cerebral cortex


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3 Major Levels of CNS Function

The spinal cord level.

more than just a conduit for signals from

periphery of body to brain and vice versa.

cord contains:

walking circuits.

reflexes circuits.


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The brain stem and subcortical

Contains:

medulla, pons, mesencephalon,

hypothalamus, thalamus, cerebellum and

basal ganglia.

Controls subconscious body activities:

arterial pressure, respiration, equilibrium,

feeding reflexes, emotional patterns.


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The Higher Brain or Cortical

Level

Higher order functions : language,

thoughts and personality

Large memory storehouse.

Each portion of the nervous system

performs specific functions, but it is the

cortex that opens the world up for onesmind.


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Organization of the Nervous System

Sensory Division

tactile, visual, auditory, olfactory.

Motor Division

respond to and move about in our

environment.

Integrative Division

process information, creation of memory.


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Figure 45-2

Somatosensory

Axis of theNervous System


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Figure 45-3

Skeletal Motor

Nerve Axis of theNervous System


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Terminology:

Afferent

VS

Efferent


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Terminology:

1st order , 2nd order and

3rd order neurons


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Histology of the NS


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Neuron

Structure


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Neuroglia


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Neuroglia

Myelination


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Neuroglia

Myelination

In PNS =Schwann cell


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Neuroglia

Form the

blood-

cerebrospinal

fluid barrier


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Neuroglia

Phagocytize


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Neuroglia

Astrocytes

Astrocytes

Astrocytes

1)Support for neurons

2)Form the bloodbrain

barrier

3)Learning and memory

4)Maintain the prober

environment for the

neurons


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Neuroglia

Astrocytes

Astrocytes

Astrocytes

1)Support for neurons

2)Form the bloodbrain

barrier

3)Learning and memory

4)Maintain the prober

environment for the

neurons

In PNS= Satellitecells


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Nervous tissue


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Nervous tissue

Gray matter : neuron cells

White natter: myelinated axons


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Synapses and Neurotransmitters


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Communication Between

Neurons Synapse:


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Neurons Synapse: A specialized site of contact, and

transmission of information between a neuron

and an effector cell

Figure 45-5

Anterior

MotorNeuron


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Neurons Electrical synapse


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Synaptic Transmission


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Action of Neurotransmitter on

Postsynaptic Neuron

postsynaptic membrane contains receptor

proteins for the transmitter released from the

presynaptic terminal. The effect of neurotransmitter on the post

synaptic neuron depend on the type of the

receptor


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Postsynaptic Neuron

Two types of receptors

Ion channels receptors


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Postsynaptic Neuron

Two types of receptors

Ion channels receptors

Second messenger receptors


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Ion Channels receptors

transmitters that open sodium

channels excite the postsynaptic

neuron.

transmitters that open chloride

channels inhibit the postsynaptic

neuron.

transmitters that open potassiumchannels inhibit the postsynaptic

neuron.


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Seconded messenger receptors(as example G-protein)

Ion

Channel

1Opening specific ion

channels

2Activation of cAMP or

cGMP

3Activation of one or more

intracellular enzymes

4Activation of genetranscription.


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Neurotransmitters

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