i want 25 multiple choice questions with their model answer below each question that covers different aspects of all of the following information : Ganglia
They are collection of nerve cells outside the central nervous system. They are of 2 types; sensory (spinal) & autonomic (sympathetic
and parasympathetic).Spinal Ganglion
1)Covered by a thick C.T. Capsule.
2) Contains no synapses
3) Contains unipolar neurons
4) Nerve cells are small, medium-
sized or large(15-100 um).
5) Nerve cells are rounded
Sympathetic Ganglion
1) Covered by a thin C.T. capsule
2) Contains synapses
3)Contains multipolar stellate neurons
4) Nerve cells show a uniform size
(25 um).
5) Nerve cells are stellateSpinal Ganglion
6) Nerve cells are arranged in group
of rows, separated by nerve and C.T
7) Nerve cells are capsulated by the
satellite cells
8) Nerve fibres may become
convoluted forming glomeruli.
9) Nerve fibres are myelinated
10) Poor blood supply
Sympathetic Ganglion
6) Nerve cells are scattered.
7) Satellite cells are only found in
large ganglia.
8) No glomeruli are formed by the
nerve fibres.
9) non myelinated
10) Rich blood supply.Synapse
Histologically: it is formed of;
1.Presynaptic
side rich
vesicles
of
in
mitochondria and
chemical transmitter (in chemical synapse).
It shows separate zones of dense cytoplasm.
2.Synaptic cleft: 20-30 nm in width.
It shows delicate fibres or granules.
3.Postsynaptic side that has receptors for the chemical
transmitter.
It shows a continuous zone of dense cytoplasm which is
associated with a network of filaments called synaptic web.NEUROGLIA
Glial cells are 10 times more abundant in the
mammalian brain than neurons.
They surround the cell bodies and processes.Astrocytes (Macroglia):
•large Star shaped cells with
multiple processes.
•They have large pale nucleus.
•They have Centrioles so can
divide &form tumors.
•By E/M, they show bundles of
intermediate filaments that keep
their shape.
•They are ectodermal in origin.
•In grey matter and white matter.Astrocytes (Macroglia):
••Functions:
1.They have processes with
expanded end feet linked to
endothelium of blood capillaries so
can control metabolic exchanges
between nerve cell and blood.
2.Blood brain barrier.
3.Structural support.
4.Repair process by formation of
scar tissue.
There are 2 types;Fibrous astrocytes
In white matter.
Cytoplasm is fibrillary.
Few long processes.
Cytoplasmic astrocytes
In grey matter.
Cytoplasm is granular.
Many short processes.Oligodendrocytes
•They are medium sized cells which
have few processes.
•medium dark nucleus.
 They have Centrioles.
 Dense dark cytoplasm
rich
in
endoplasmic reticulum, Golgi
body, ribosomes and mitochondria.
 Ectodermal in origin.
Present in both grey and white matter.
There are 2 types;Interfasicular
Oligodendrocytes
Satellite
Oligodendrocytes
In white matter
in between bundles of axons
Formation of myelin sheath
and electric insulation
In Grey matter
closely associated with
the cell body of neurons
Support nerve cells.Microglia (mesoglia):
•Small cells with many branches.
The cell body and the branches are
decorated by spines.
•Oval dark nucleus.
•Cytoplasm is scanty rich
with lysosome.
•No Centrioles.
•Mesodermal in origin.
•In grey and white matter.
•Phagocytic cells.
•stained by vital stains as trypan blue.Ependymal cells • Line central canal of spinal cord and ventricles of brain. • They form simple cuboidal or columnar epithelium that may be ciliated in places. Cilia may be involved in propulsion of CSF. •Ectodermal in origin. Schwann cells
• In peripheral nervous system. • Responsible for myelin production, electric insulation and regeneration. • Ectodermal in origin.Satellite cells
• Low cuboidal cells,
• In peripheral nervous system.
• Around nerve cells in ganglia.Main functions
Functions of neuroglia cells Glial cell type
1 . Metabolic exchange. 2. Blood- brain barrier. 3. Structural support. 4. Repair processes.
Astrocytes
Myelin production, electric insulation. Oligodendrocytes Phagocytic activity
Microglia
Myelin production, electric insulation, regeneration.
Lining cavities of central nervous system
Schwann cells Ependymal cells