Nerves Flashcards
Where are ganglion located?
Outside CNS
What does the central nervous system consist of?
Brain and Spinal cord
What does the peripheral nervous system consist of?
Everything except brain and spinal cord
What is the cell body called?
Soma, perikaryon
What is Nissl substance and where is it located?
Clumps of rER located in the cell body and dendrites
Does the soma have a nucleolus?
Yes
What is the background of nervous tissue called?
Neutropil
Do dendrites conduct signals toward or away from the soma?
Toward
D axons conduct signals towards or away from soma?
Away
When do axons not transmit information away from the soma?
Pseudounipolar neurons
What cells produce myelin in the central nervous system? Peripheral?
Central: oligodendrocytes
Peripheral: Schwann cells
What are the 3 types of neuron shape?
Bipolar, pseudounipolar, multipolar
What are bipolar neurons used for?
Sight, hearing, smell
What are pseduounipolar nerves used for?
Regular sensory neurons
What are multipolar neurons used for?
Most motor neurons
Where can synapses occur?
Cell body, axons, dendrites
What is bodain classification of neurons?
Dendritic zone (area that is stimulated/inhibited)
Axonic zone (conducting part)
Telodendritic zone (terminal mods that allow for transfer of information at synapse)
What is the bodain classification of a bipolar neuron?
Dendritic zone: Dendrites
Axonic zone: Axon & cell body
Telodendritic zone: End of axon
What is the bodain classification of a pseduounipolar neuron?
Dendritic zone: on lower part of neuron
Axonic zone: Axon, cell body
Telodendritic zone: right above cell body
What is the bodain classification of a multipolar neuron?
Dendritic zone: Dendrites & cell body
Axonic zone: Axon
Telodedritic zone: End of axon
What are the neuroglial cells of the central nervous system?
Astrocytes, Microglia, Oligodendrocytes, Ependymal cells
What are the glial cells of the peripheral nervous system?
Satellite cells (ganglionic gliocytes)
Schwann cells (neurolemmocytes)
What is the purpose of neuroglial cells?
To provide support to the central nervous system because there is little CT
Form scars by proliferating astrocytes after injury
Nutrition, communication
What is an astrocyte?
Largest neuroglial cell
Protoplasmic is found in grey matter
Fibrous is found in white matter (surround nodes of ranvier)
What is the purpose of astrocytes?
Recycle neurotransmitters, maintenance of synapses, maintain the blood-brain barrier, antigen-presenting
What diseases are astrocytes key in?
Alzheimers, ALS, Alexander’s disease
Where are oligodendroglia located?
In the CNS
In grey matter near perkarya to produce myelin
In white matter to produce myelin
How many neurons can one oligodendrocyte envelop?
Several
What are ependymal cells?
Line cavity of brain and spinal cord
Contribute to formation of Cerebrospinal fluid
Stem cell properties (proliferate in response to injury, generate neuroblasts and astrocytes)
What are microglial cells?
Small and dense phagocytic cells
What is the bouton?
Expanded area of the axon that contributes the presynaptic membrane
Describe the synaptic cleft
Gap between neurons that contains fine filaments and electron dense material
What is the subsynaptic web?
Filamentous materials associated with the post synaptic membrane
What is the tripartite synapse?
Astrocytic processes at the synaptic cleft form connections with neuronal synapses and each other with gap junctions
Does neurogenesis occur?
Yes, throughout life.
Neural stem cells have astrocytic and neuroepithelial potential
Ependymal cells of the central canal are pluripotential
What is dedifferentiation?
Progenitor cells are mono or uni-potent. If a cell becomes bipotent it has dedifferentiated to a stem cell
What is transdifferentiation?
A cell becoming a cell type from a different embryonic lineage
Where is epineurium located?
Around entire nerve fiber
Where is perineurium located?
Around each fasicle
What are the perineural cells?
A sleeve-like layer of epithelioid cells immediately around fasicles
What is endoneurium?
Surrounds individual axons (along with myelin)
How many neurons can schwann cells envelop?
One, many schwann cells on one axon
Describe unmyelinated fibers
Several nerve fibers sit in simple clefts of schwann cells
What is the gap between schwann cells called?
Node of ranvier
What is each separate myelin segment referred to as?
Internode
Why don’t myelin sheaths stain?
They’re made of mostly lipids
Where are satellite cells located?
Surrounding the perikarya in the ganglion
What neuron types do not leave the CNS?
Interneuron, upper motor neuron
What are the 3 layers of connective tissue that surround the CNS?
dura mater (outer) arachnoid (inner) pia mater (inner)
What space is filled with CSF?
Subarachnoid space
