Neurons, Glia, Brain Tissue Flashcards
White matter contains mostly _____.
myelinated axons
Myelin consists of?
fat/lipid bilayers
Gray matter is collections of ___, ____, and _____.
cell bodies, dendrites, synapses
Cell bodies all live in the _____.
gray matter
What is a ganglion?
a collection of neural cell bodies outside of the CNS
This is a collection of neural cell bodies outside of the CNS.
a ganglion
What is a primary afferent neuron?
the first neuron that receives info from the outside world and relays it toward the CNS
This is the first neuron that receives info from the outside world and relays it toward the CNS.
a primary afferent neuron
What is a primary efferent neuron?
the first neuron that directs info from the CNS to the effector cell
This is the first neuron that directs info from the CNS to the effector cell.
a primary efferent neuron
What are glial cells?
the supportive cells
Neurons contain many mitochondria and distinctive collections of rough ER called _____.
Nissl substance (Nissl bodies)
Neurons contain many mitochondria and distinctive collections of ____ called Nissl substance (Nissl bodies)
rough ER
Can the CNS axons regenerate?
yes, but the astrocytes prevent regeneration
Name 6 functions of glia.
potassium buffering recycling of neurotransmitters nutrient support myelination BBB supply of growth and trophic factors
Name the cell that possesses these functions? potassium buffering recycling of neurotransmitters nutrient support myelination BBB supply of growth and trophic factors
glial cell
Conduction in a neuron (pathway) is?
dendrite–> cell body (soma)–> axon
In general, axons of this diameter are myelinated.
> 1 micrometer
In general, axons >1 micrometer diameter are ______.
myelinated
What is a synapse?
where the end of an axon contacts the dendrite of the next cell
This is where the end of an axon contacts the dendrite of the next cell.
a synapse
Most synapses are ____ in nature.
chemical
Where are NTs packaged?
in vesicles in the presynaptic terminal
When an AP reaches the terminal, _____ influx permits fusion of the vesicles within the plasma membrane, thereby dumping NT.
Ca++
Name 2 general classes of NT receptors.
ionotropic and metabotropic
What is an ionotropic receptor?
a receptor that allows the flow of ions to depolarize or hyperpolarize a cell
This is a receptor that allows the flow of ions to depolarize or hyperpolarize a cell.
ionotropic receptor
What is a metabotropic receptor?
receptors that activate 2nd messenger systems w/I the neuron
This is a receptor that activates 2nd messenger systems w/I the neuron.
metabotropic receptors
Name 3 types of glial cells within the CNS.
microglia
oligodendrocytes
astrocytes
What is the major type of glial cell in the PNS?
Schwann cells
What are microglia?
tiny, phagocytic glial cells in the CNS
arise outside the neural tube
key role in chronic pain syndrome
Name 2 types of glia that form myelin.
oligodendrocytes and Schwann cells
What is an oligodendrocyte?
cells that form the myelin in the CNS; can myelinate several axons
Name the cell:
tiny, phagocytic glial cells in the CNS
arise outside the neural tube
key role in chronic pain syndrome
microglia
These cells form the myelin in the CNS; can myelinate several axons
an oligodendrocyte
What is a Schwann cell?
cells that form the myelin in the PNS; can myelinate only one axon
These cells form the myelin in the PNS; can myelinate only one axon.
Schwann cells
What is an astrocyte?
large, star-shaped glia maintain ionic equilibrium remove extra K+ clear and recycle NTs convert glutamate to glutamine envelop all CNS blood vessels and regulate blood flow
Name the cell: large, star-shaped glia maintain ionic equilibrium remove extra K+ clear and recycle NTs convert glutamate to glutamine envelop all CNS blood vessels and regulate blood flow
an astrocyte
Minor damage to peripheral nerves is usually repaired by _____, which is facilitated by _____.
regeneration of the damaged axons; Schwann cells
What happens when the CNS is damaged?
oligodendroglia don’t clear the debris; a glial scar is formed to prevent axonal regeneration
How are proteins transported from the nucleus to the axon terminal and back?
by axoplasmic flow
What is axoplasmic flow?
the active transport of proteins from the nucleus to the axon terminal and back
What does the nucleolus do?
it makes the ribosomes
Neurons make a larger diversity of _____ and a larger amount of them.
proteins
What are breaks in the myelin sheath called?
Nodes of Ranvier
What is a Node of Ranvier?
a break in the myelin sheath
Myelin increases conduction velocity by a factor of ___.
10
A local increase in neuronal activity results in a substantial increase in _____.
local blood flow
What is an increase in neuronal activity, thereby increasing blood flow, called?
functional hyperemia
How is blood flow increase with increased neuronal activity?
they release NO and nearby astrocytes convert glutamate to EET to dilate the BVs
