nervous system cells Flashcards
neurons
nerve cells
-information processing
-signaling units
multipolar
multiple dendritic projections coming off the cell body and usually an axon
bipolar
two processes coming off the cell body
-CN 8 cells
pseudounipolar
cell body with one thing coming off and then decided to have the arm going in two direction, dendritic side and axon side (impulse goes from dendrite side to the axon side), axon terminals
soma (perikaryon)
cell body
-supports metabolic and synthetic needs
dendrites
branching processes
-receiving information from other neurons
axons
conducts information away from the cell body and to other neurons or other organs
glial cells
a type of supportive cells referred to as “the glue”
-supply firmness and supports chemical environments
schwann cells
specialized glial cells, flattened
-within the PNS
-produces myelin
-protective and insulating coating around axonal segments PNS neurons
what does myelin do
increases speed of transmission of action potentials to carry the electrical signals/messages
phagocytes
part of immune system that helps remove debris from immune system
-cleaning up
oligodendryocytes
forms myelin shealth around neurons in the CNS
-within CNS glial cells
1 oligodendrocytes goes to _______ axons in the CNS
20 to 60
astrocytes
provides structural and metabolic support within the CNS
ependymal cells
lines ventricles within the CNS
microglia
become active in response to antigens
-makes up about 5-10%
PNS vs. CNS
PNS : no meninges, neurons, glia (schwann)
CNS : covered by meninges, neurons, glial cells
separation of fluid
extracellular space, intracellular compartments and cell membrane
what is the cell membrane
bilayer of lipid molecules and protein molecules
-maintains ion concentrations, selectively permeable
-active pumping mechanism
types of synapses
axo-somatic, axo-axonic and axo-dendritic
-synapse can be with another neurons or with a muscle at the neuromuscular junction with a gland
axo-somatic
axons with soma synapse
axo-axonic
one terminal bouton with another terminal bouton
axo-dendritic
one axon is carrying information with dendrite of next cell
nuclei
groups of functionally related cell bodies in the CNS
-such as cochlear nuclei
collections of axons within the CNS
fasciculus, funiculus, lemniscus, peduncle, and commonly tract (such as optic tract)
ganglia
clusters of functionally related cell bodies in the CNS
-such as spiral ganglia
nerve
axons in the PNS for the peripheral nerves
details of myelin
lipids and proteins, wrapping axons, nodes of ranvier (bare space where there is no myelin) and insulation
endoneurium
individual fiber wrapped in this
perineurium
several axons with individual endonerium
-this is what wraps around that
epinerurium
what wraps around a bundle of perineurium
gray matter
cell bodies and dendrites
-nuclei functionally related cell bodies in the CNS
white matter
mostly axons due to the myelin sheath around many axons
-myelin is mostly composed of lipids and has a fatty white appearance
multiple sclerosis
autoimmune disorder, destruction of myelin in patchy areas of CNS, slowing and failure of AP conduction
-muscle weakness
guillain barre
autoimmune attack on peripheral nerves
-patchy demyelination
-slowing and failure of AP conduction
