Neurons, Glia, and Brain Tissue Flashcards
In general, white matter is _________ to gray matter in the cortex. In the spinal cord, however, it is opposite: ___________.
deep; gray matter is on the inside
Tracts, peduncles, and fasciculi are all examples of ______ matter.
white matter
Nuclei are an example of _________ matter.
gray
Once stimuli pass from dendrites to the cell body, the _________ regulates whether the signal will continue down the axon.
axon hillock
What stain selects for RNA?
Nissl
Why do neurons need to make a lot of protein?
They are large cells, requiring extensive cytoskeletons to transport proteins to the periphery of axons and dendrites.
Which kind of neuron (peripheral or central) can regrow damaged axons?
Peripheral (CNS axons can regrow – demonstrated in vitro – but they are prevented from doing so by astrocytes)
Stacks of rough endoplasmic reticulum are called ___________.
Nissl bodies
Necrosis due to damaged axons is called ___________.
chromatolysis (loss of coloring)
What are myelin cells in the CNS called?
Oligodendrocytes or oligodendroglia
What are myelin cells in the PNS called?
Schwann cells
Embryologically, the nervous system comes from _____-derm.
ecto-
The microglia are the __________ of the brain.
macrophages
Why does ATP activate microglia?
ATP outside cells is a sign of lysis
What are the three types of supportive cells in the CNS?
Astrocytes
Oligodendrocytes
Microglia
Astrocytes provide what function in the CNS?
They fill in the spaces between cells.
What is the most common neurotransmitter?
Glutamate
What cell type is responsible for maintaining the blood-brain barrier?
Astrocytes (by instructing endothelial cells to form tight junctional complexes preventing leakage of plasma into extracellular space)
List the functions of astrocytes.
- Neurotransmitter clearance
- Neuronal support
- Blood-brain barrier
- Local control of blood flow
What is the cellular difference between white and gray matter?
White matter is myelinated.
The white matter can be thought of as merely the ______________.
cables connecting the processing areas of the brain
Cell bodies all live in ________ matter.
gray
Most pathways are named using a __________ system.
“from-to” (so the corticospinal tract connects the motor system in the cortex to the spin)
In terms of action potentials, how do dendrites and cell bodies differ from axons?
Dendrites and cell bodies are generally passive – meaning the electrical signal decreases with distance – while axons have voltage-sensitive channels that propagate an action potential.
In general, axons greater than ________ are myelinated.
1 micron
Recent research has indicated that __________ dysfunction may be a source of chronic pain.
microglia
Unlike oligodendrocytes, which can myelinate _________ cell(s), Schwann cells can myelinate ________ cell(s).
many; only one
___________ envelop all blood vessels in the central nervous system.
Astrocytes
What two sites in the brain do not have the blood-brain barrier?
The circumventricular organs: caudal medulla and the hypothalamus
By what two mechanisms do neurons communicate to the blood vessels that they need more oxygen?
They generate NO (which itself causes vasodilation); and the increased in glutamate uptake by astrocytes leads to activation of a phospholipase that produces EET; EET leads to hyperpolarization of the arteriolar membrane and thus vasodilation.
