Neurons and Neuroglia Flashcards
What is the role of a neuron?
Transmit electrical signals
What is the role of neuroglia?
Support cells
What is the compo. of gray matter?
Cell bodies
What is the compo. of white matter?
Fiber tracts/axons
What are clusters of nuclei in CNS?
Nuclei
What are clusters of nuclei in PNS?
ganglion
What are the bundles of axons in CNS?
Fasicles
What are the bundles of axons in PNS?
Nerves
What is the stain for gray matter?
Nissl (crystyl violet)
What is the stain for white matter?
Hematoxylin-based like Weil
Can neurons divide/regenerate after prenatal development?***
NO
What is the function of a dendrite?
Receive signals from cells
What is the function of a cell body/soma?
1) Metabolic support for the cell (MTCH)
2) Protein synthesis (A LOT of RER)
What is the function of axons?
Carry action potentials long distances to other cells.
Where is the usual point for initiation of electrical impulses?
Axon hillcock
In the dendrite of a neuron, where is the site that other cells synapse?
Dendritic spine
What are the side branches of axons?
Collaterals
What do axons terminate in?
Synaptic bouton
What do axons contain for neurotransmitter transport?
Microtubules
What transports molecules from boutons to soma in a neuron, and what is this process called?
Dynein; retrograde
What transports molecules from soma to synaptic nerve-endings and what is this process called?
Kinesin; Anterograde
What is convergence?
A single neuron can receive input from many sources
What is divergence?
The axon of a neuron can branch to affect cells in different locations.
What kind of neurons converge?
Motor
What kind of neurons diverge?
Sensory
Are there more sensory neurons or motor neurons?
Sensory
Where would you find interneurons?
CNS
What species has unipolar neurons?
Invertebrates
What is a unipolar neuron?
Have only an axon. Smallest nerve cell
What is a bipolar cell?
1) Oval-shaped soma
2) A dendrite
3) Axon
What cells are mostly bipolar?
Sensory cells (optical field)
What are multipolar neurons?
1) Single axon
2) Many dendrites
What cells predominate in the nervous system of vertebrates?
Multipolar
What organelle does the cell body/soma of a neuron have A LOT of?
RER for protein synthesis
What cells dominate in # in the brain?
Neuroglia
What is the key role of glia?
Maintains homeostasis and a healthy environment for the cell.
What are the 4 main types of glia?
1) Astrocytes
2) Ependymal cells
3) Oligodendrocytes/Schwann cells
4) Microglia
What glia 1) line the fluid-filled ventricular spaces of the brain, 2) secrete CSF?
Ependymal cells
Which glia are 1) the most abundant 2) Pick up excess K+ 3) involved in glia-neuronal migration development 4) form tight junctions in BBB?
Astrocytes
What cells secrete myelin in the CNS?
Oligodendrocytes
Which cells secrete myelin in the PNS?
Schwann cells
How many axons do Schwann cells myelinate at a time?***
ONE
How many axons do oligodendrocytes myelinate at a time?***
MANY
How does myelination affect nerve transduction?
Speeds it up!
Do nodes of Ranvier have myelin?
NO
What happens when large areas of axon lose myelin like in PD/multiple schlerosis?
Propagation is slowed or stopped entirely due to the lack of V-gated channels in the bared internodal areas.
Where do microglia reside at?
Gray matter (think greying hair)
What do microglia derive from?
Monocytes
What do resting/happy microglia look like?
Small body with long processes
What do active/angry microglia look like?
Fat body with short stubby processes
What do microglia release when they are activated?
Cytokines
What population has elevated cytokine levels?
Aged people
Can microglia become deadly when there is prolonged activation like in AD and PD?
Yes. Not good.
What food should you eat to reduce inflammation and decrease microglia activity?
Blueberries.
