Glia and Neurons Flashcards
What is the “cell theory” and who proposed it?
The tissues of all organisms are composed of cells
Proposed by T. Schwann
What is the “neuron doctrine” and who proposed it?
Neurons are special cases of the cell theory
Proposed by Ramon y Cajal
Ramon y Cajal used _____ studies and the methods developed by _____ to show that neurons are not continuous.
lesion/degeneration
Golgi
Transmission of nerve impulses shows a _____.
delay
Flw of information in a neural chain is _____.
unidirectional
Transmission at synapses was found to be _____ as well as ______.
excitatory
inhibitory
“Glia” comes from the Greek word for _____.
glue
Glia cells outnumber neurons by a ration of ~:
Ratios vary considerably by brain area.
3
1
_____ surround neurons and hold them in place.
Astrocytes
_____ and _____ supply nutrients and oxygen to neurons.
Astrocytes
Ependymal cells
_____ insulate one neuron from another.
Oligodendrocytes
_____ destroy pathogens and remove dead neurons.
Microglia
_____ modulate neurontransmission by making more or less neurotransmitter-precursor available.
Astrocytes
Microglia are _____.
phagocytes
Microglia arise from _____ of blood cells outside the CNS.
progenitors
In microglia’s “resting state,” they _____.
move around and survey their domain for debris.
After injury or inflammation, microglia are _____ and migrate to the site of injury to help clear dead and dying cells.
activated
Microglia _____ the debris in the brain.
phagocytose
wrap around and “swallow”
Microglia can also produce small molecules called _____ that trigger cells of the immune system to respond to the injury site.
cytokines
Microglia can become _____, which contributes to neurodegenerative disorders.
overactivated
Macroglia consist of _____ and _____.
astrocytes
oligodendrocytes/schwaan cells
Astrocytes have numerous projections that anchor neurons to the _____.
blood supply
Astrocytes regulate the external chemical environment of neurons by removing _____.
excess ions
particularly potassium
Astrocytes form the _____ that protects the brain.
blood-brain barrier
Astrocyte activity is linked to _____ in the brain, and this is what is acutally being measured in _____.
blood flow
fMRI
Astrocytes are important for neurotransmitter _____ and _____ of the metabolic activities of neurons.
synthesis
regulation
Astrocytes take up and recycle _____ and _____ that are released at synaptic clefts.
GABA
glutamate
Astrocytes release _____ which can be used by neurons to make new glutamate and/or GABA.
glutamine
In the CNS, myelin is made by _____.
oligodendrocytes
In the peripheral nerves, myelin is made by _____.
Schwann cells
Each Schwann cell makes one segment of _____.
myelin
Each oligodendrocyte makes multiple segments of myelin that wrap around _____ axons.
several
_____ is an autoimmune disease that often progresses to physical and cognitive disability.
Multiple sclerosis
Onset of MS usually occurs in _____.
young adults
The name “multiple sclerosis” refers to the scars in the _____.
white matter
MS is typically _____ or _____.
relapsing remitting (discrete attacks) slowly progressive
MS destroys _____.
oligodendrocytes
MS results in a thinning or complete loss of _____ and, less frequently, the transection of the _____.
myelin
axons
Ramon y Cajal used _____ studies and the methods developed by _____ to show that neurons are not continuous.
lesion/degeneration
Golgi
_____ modulate neurontransmission by making more or less neurotransmitter-precursor available.
Astrocytes
_____ arise from neuroepithelial cells (_____) after the onset of neurogenesis.
Radial glia cells
stem cells of the nervous system
In the _____ nervous system, radial glia function both as neuronal progenitors and as a scaffold upon which newborn neurons migrate to _____.
developing
guide the growth of neurons
In the _____ brain, the _____ and _____ retain some radial glial cells
mature
cerebellum
retina
Pseudo-unipolar cell contains no _____, but an axon that splits into _____ branches.
dendrites
2
(peripheral nervous system/spinal cord)
At rest, the neural membrane is mostly permeable to _____ ions.
potassium (K+)
The so-called “resting-membrane potential” is maintained by the _____ pump.
Na+-K+
Shifts in neuronal potential either excite the neuron
(_____ = excitatory), or inhibit the cell
(_____ = inhibitory)
depolarization
hyperpolarization
Identity of information (e.g. sensory input) is based on _____.
wiring
Intensity of the action potential is based on _____.
frequency
