neurohistology Flashcards
Excitatatory neurotransmitters
Glutamatergic neurons
Cholinergic neurons
Inhibitory neurotransmitters
GABAergic neurons
Glycinergic neurons
Modulatory / polymodal neurotransmitters
Neurons that release biogenic amines :
noradrenergic, adrenergic, dopaminergic
Bipolar neurons which have one axon and one dendrite are in
○ olfactory cells of the nose,
○ certain neurons of the retina, and
○ sensory neurons of the ear.
Unipolar neurons r located in
spinal (dorsal root) ganglia
and sensory ganglia
of cranial nerves
(CN) 5,7,9,10,
Structural classification of Neurons
●Unipolar/Pseudounipolar
● Bipolar
● Multipolar
● Anaxonic (In retina)
Golgi type 1 neurons are known for having
long axons ( i.e span a long distance )
Golgi type 1 neurons include
○ Pyramidal cells of the cerebral cortex
○ Purkinje cells of the cerebellar cortex
○ Motor cells of the spinal cord
Golgy type II neurons are known for _____
their short axon
the structure. of Golgi type 2 neurons which give them a star-shaped
appearance;
short dendrites
Golgi type 2 neurons are numerous in
cerebral and
cerebellar cortex and are often inhibitory
in function.
Aggregation of polysomes and Rough endoplasmic reticulum found in the perikaryon ( cell body ) of neuorons
Nissl substance ( NT : NOT IN AXON/AXON HILLOCK)
In axonal transport - movement away from the soma down the axon
- movement up the axon toward the soma
Anterograde transport
Retrograde transport
Axonal transport may be inhibited by ——— which depolymerizes
microtubules.
Colchicine
FAST ANTEROGRADE (by kinesin )occurs at the rate
of
200-400mm/day
FAST RETROGRADE (by dynein) occurs at the rate of
100-200mm/day
SLOW ANTEROGRADE occurs at the rate of
1 to 5
mm/day.
NT:
Damaged nerves regenerate at a
speed governed by slow axonal
transport.
CNS neuroglia not derived from neural crest
microglia
cells for regeneration of damaged PNS nerve fibers
Schwann cells. ( separated by nodes of ranvier )
fibrous astrocytes are in
Protoplasmic astrocytes are in
white matter
gray matter
cells associated with ependymal cells
Tanycytes
The anterograde degeneration
characterized by the disappearance of axons and myelin
sheaths and the secondary proliferation of Schwann cells.
Wallerian degeneration
The result of retrograde degeneration in
the neurons of the CNS and PNS resulting in loss of Nissl substance
Chromatolysis
A 10-year-old boy has severed his radial nerve. Which of the following cells
plays a major role in axonal regrowth?
(A) Fibrous astrocytes
(B) Fibroblasts
(C) Oligodendrocytes
(D) Protoplasmic astrocytes
(E) Schwann cells
(E) Schwann cells
