Nervous system

Central nervous system (C.N.S.)

Prepheral nervous system

(P.N.S.)

Type of nervous system

Organization of the Nervous System

Figure 8-1: Organization of the nervous system

P.N.S.

Nerve :Nerve Fiber: Axons + Sheathe cells

(Schwan cells, oligodendrocyte )

Ganglion :

Perikaryons + dendrites + axons (first portion)

Satellite cells

Cells of nervous system

NeuronNeuroglia

Neuron

Neuron

Perikaryon

Perikaryion

Trigger Zone: Cell Integration and Initiation of AP

Trigger Zone: Cell Integration and Initiation of AP

Figure 8-8b: Subthreshold and suprathreshold graded potentials in a neuron

Dendritic spine

Axonal transport

Axonal transport

Antrograde Slow stream ( a few mm per day)

transport protein and microfilament Intermediate

transport mitochondria Fast stream (400mm per day)

transport substance that contained in vesicle Retrograde

Mechanism of the axonal transport

Dynein and kinesin

Axonal transport

Types of Neurons

Diverse Neuron Forms and Functions

Figure 8-3: Anatomic and functional categories of neurons

Types of neurons

MotorSensoryInterneuron

Wave of depolarization

Synapes

Electrical

Chemical

Synapse

Synapse

Metabolism and Synthesis in a Neuron

Figure 8-4: Axonal transport of membranous organelles

Membrane & Channel Changes during an Action Potential

Type of synapses

AxosomaticAxodendriticAxoaxoticDendrosomaticDendrodendroticdendroaxotic

Synapses transmit information

Neurotransmiter

Open or close ion channel or initiate second message

Neuromodulator

do not act directly on synapse but modify neuron sensitivity

Neuroglia

Astrocyte Protoplasmic Fibrous Oligodendrocyte Microglia Ependymal Schwann Satellite cell

Glial Cell Functions

Figure 8-5: Glial cells and their functions

Function of the astrocytes Regulating vasodilation within the CNS moving nutrients, wastes, and other metabolites between neurons and capillaries. Repair Guiding and physically supporting movements and locations of

differentiating neurons in the developing CNS Respond to several stimuli Influence on neuronal survival and activity by regulating constitutes of

ECM, absorb local access of neurotransmitter, release metabolites and neuroactive molecules

Extending processes that associate with or cover synapses in the CNS, affecting the formation, function, and plasticity of these structures.

Forming a barrier layer of expanded processes, called the glial limiting membrane

Astrocytes connect via gap junction very large cellular network for the coordinated

regulation of their various activities in different brain regions

Blood brain barrier

Neuroglia

Oligodendrovyte

Neuroglia

Nerve Fiber

Myelinization

Myelination

Myelination

M.MONSEFI

Myelinization

Nerve Fiber

Myelinated & Un

myelinated

Oligodendrovyte

Schmit-lanterman

Node of Ranvier

Nerve

Nerve

Nerve

Nerve

Repair Of

Injurednerve

Ganglions

Sensory

1:Cranial

2:spinal(dorsal root)

Autonomic

1:Sympathic

2:parasympathic

Ganglia

Ganglia

Sensory Ganglion

Sensory Ganglion

Autonomic Gangilion

Atonomic ganglia

Sensory ganglia Autonomic ganglia Pseudounipolar Larger Associated with

craniospinal nerves No synapses Nerve that enter or exit

belongs to one kind of neurons

Multipolar Smaller Associated with

autonomic nerves Has synapses Nerve that enter or exit

belongs to different nerves

C.N.S. (Brain & Spinal cord)

gray mater : perikarions + dendrites + axons (first portion)

protoplasmic astrocytes + oligodenrocytes + microglia

White mater : axons fibrous astrocytes + oligodendrocytes +

microglia

Braincerebellum

spinal cordspinal nerve

Spinal cordGray mater

Dorsal horn

(sensory neurons)

Ventral horn

(motor neurons)

Epandymal canal

White mater

Myelinated &

Unmyelinated axon

Summary Slide

Spinal cord

Anterior horn cell

Meninges

Dura matterArachnoid Pia matter

Meninges

Choroid plexus

Choroid Plexus

Brain

Cerebellum Gray mater

Molecular layer

Purkinje cell layer

Granular layer

White mater

Myelinated &

unmyelinated axons

Cerebellum

w.m.

White mater granular layer molecular layer

M.MONSEFI

White mater granular layer purkinje cell layer molecular layer

M.MONSEFIM.MONSEFI

Cerebellar cortex

Cerebellum

Cerebrum

Types of the cells in cerebrum

Autonomic system

FunctionTwo neuron networkPreganglionic fiberPostganglionic fiber

Type of Autonomic Fibers

Sympathetic systemParasympathetic system