CHAPTER 2:  MICROSCOPIC BASIS OF NEUROANATOMY

 

 

Histology

 

1. Neurons  (Nerve Cells); (with Chromatophil Substances & Neurofibrils/Microtubules)

* Parts:

a.  Dendrites

b.  Cell Body (Soma)

c.  Nucleus

d.  Axon Hillock

e.  Axon

f.  Myelin Sheath

g.  End Brush (Telondria)

h.  Boutons Terminaux  (Synaptic Knobs)

i.   Synaptic Vesicles

* Reactions to Injury:

a.  Eccentricity of Nucleus

b.  Chromatolysis

c.  Degeneration  (Retroactive/Retrograde & Wallerian)

* Types:

a.  According to Function

a.1.  Sensory/Afferent

a.2.  Motor/Efferent

a.3.  Internuncial/Intercalated/Connector

            b.  According to Number of Processes

b.1.  Unipolar

b.2.  Bipolar

b.3.  Multipolar

 

 µ AXON  (Nerve Fiber)

      * Parts:

            a.  Internode/Internodal Segment

            b.  Node of Ranvier

            c.  Schwann Cells

            d.  Myelin Sheath

            e.  Neurofibrils/Microtubules

            f.  Axoplasm

            * Types:

            a.  Myelinated with Neurolemma

            b.  Unmyelinated with Neurolemma

            c.  Myelinated without Neurolemma

            d.  Unmyelinated without Neurolemma

 

]     Saltatory Transmission  (myelinated fibers conduct impulses faster)

 

2. Synapses

* Types:

a.  Axosomatic

b.  Axodendritic

c.  Axoaxonic  (Presynaptic Inhibition)

 

3. Neuroglia  (Glial Cells)

* Types:

a.  Oligodendrocytes / Oligodendroglia

b.  Astrocytes / Astroglia

w  Types of Astrocytes:

b.1.  Fibrous

b.2.  Protoplasmic

w  2 Functions of Astrocytes:

b.1.  Supporting framework

b.2.  Cover synaptic contacts between neurons

b.3.  Absorb some neurotransmitters  (glutamate & GABA)

c.  Microglia

d.  Ependyma