Nervous tissue( Neuroglia, Myelination, and Nuerons)

Astrocytes (Neuroglia > CNS)

largest and most

numerous/make up the blood

brain barrier (BBB)

Oligodendrocytes (Neuroglia > CNS)

form

myelin sheath/form internodes

and myelin sheath gaps (grey and white matter)

Microglia (Neuroglia > CNS)

these are

phagocytic cells(remove waste)

Ependymal Cells (Neuroglia > CNS)

involved in

cerebrospinal fluid (CSF)

production, make up cellular lining(ependyma)

The cell bodies in the PNS are

clustered in

ganglia

Myelination sections

internode(protection) and seprates the internodes are nodes(no protection)

Myelination

a Schwann cell wrapping a single Axon

Axons are bundled together to form

peripheral nerves

Satellite Cells (Neuroglia > PNS)

surround cell

bodies

Schwann Cells: neurolemmocytes (Neuroglia > PNS)

surround

Axons, consist of:

• Axolemma /

neurolemma

Perikaryon

neuron cytoplasm

Neurofilaments/ Neurotubules

make up the neuron cytoskeleton

Nissl bodies

clusters of free

ribosomes

Axon hillock

area where the

initial segment connects to the

cell body

Axoplasm

cytoplasm of the

axon

Collaterals

branches off the

axon

Telodendria

ends of

the axon and

collaterals

Axon terminals

ends

of the telodendrias

Axoplasmic

transport

the

movement of material

between the cell body

and the axons

Structural classification

Based on the number of

processes extending

from the cell body

Functional classification

– Sensory

– Motor

– Interneuron (involved

with both sensory and

motor)

Anaxonic

– Has many processes but

cannot differentiate between

axons and dendrites

– Found only in the CNS

Bipolar

– The cell body is between the

dendrite and axon

– Axons are not myelinated

Pseudounipolar

– The cell body is off to one

side of the axon

Multipolar

– Typically has a single axon

and multiple dendrites

– Most common type in the

CNS

Functional Classification of Neurons 3 groups

Sensory neurons - Motor neurons - Interneurons

Sensory (afferent division)

Neurons

– The axons are afferent fibers

– Sends information from the

PNS to the CNS

Interoceptors (Sensory)

monitor

internal organ activity

Exteroceptors (Sensory)

provide

information about the

external environment

Proprioceptors (Sensory)

monitor

position and movement

Motor Neurons

– The axons are efferent fibers

– Send information from the

CNS to the periphery

Somatic nervous system

(SNS) Motor

consists of somatic

motor neurons

Autonomic nervous system

(ANS) Motor

consists of visceral

motor neurons, preganglionic fibers

and postganglionic

fibers

Interneurons

– Located entirely in the CNS

– Situated between the motor and

sensory neurons

– Analyze sensory input and

coordinate motor outputs

– Can be excitatory or inhibitory