Lecture 2: Neurons and Glia Flashcards
Neurons….
are post-_____
derive from the _____
have what components?
make ______
Neurons…
are post-mitotic
derive from the ectoderm
have soma, dendrites, and axons
make synapses
Who came up with the Neuron Doctrine?
Cajal
Neurons communicate with ______
Information flows from the _____ to the ____
Neurons communicate with directionality
Information flows from the soma and dendrites to the axon and synaptic terminals.
Directionality:
MOST information travels from ____
BUT retrograde transport can occur where
- Post synaptic element can release _____ that can affect the presynaptic neuron
Explain examples of retrograde axonal transport
Most information travels from presynaptic neuron to post
BUT retrograde axonal transport can occur: post-synaptic elements can release trophic factors that can affect the presynpatic neuron
Examples:
muscles can send trophic factors to motorneurons
Varicella Zoster (chicken pox)
Poliovirus
What are the “main effectors” of the nervous system?
The main effectors of the nervous system are neurons
What are “glia”?
And how many of them are there compared to neurons?
Glia are non-neuronal cells within the nervous system
They contribute to development, structure. and provide the correct enviornmental factors and help repair neurons.
There are 10 x more glia than neurons
Explain the difference between Microglia and Macroglia.
Microglia: small glia, they only function during damage and disease
NOTE: you will only see microglia functioning in damaged or diseased tissue
Macroglia: large glia… 80-90% of all glia
What are the three main types of macroglia and what are their basic functions?
Macroglia:
- Schwann cells (myelinate peripheral axons)
- Oligodendrocytes (myelinate the CNS axons)
- Astrocytes (do a lot of things, help with cytotoxicity)
What is the innate immune system of the CNS?
Microglia
What are microglia?
Where are microglia found?
When are they reactive?
Microglia are the “innate immune system” of the CNS
They are tissue macrophages that populate the CNS during early embryonic development
They are found in all regions of the brain and spinal cord (CNS)
They become reactive during disease (HIV, Alzhiemer’s, parkinson’s)
Evidence shows they can be neuroprotective and neurotoxic at different stages of disease
Astrocytes make close contact with _______
Astrocytes make close contact with SYNAPTIC TERMINALS
Astrocytes influence the synaptic response by releasing ______
Astrocytes influence the synaptic response by releasing Glutamate
Glial glutamate release can influence neighboring neurons
Remember, astrocutes are close to synaptic cleft
Explain how neuronal activity can induce calcium signaling in astrocytes
Astrocytes are electrically coupled and connected via connexons
Ca signaling spreads between astrocytes, forming calcium waves
This occurs via IP3 diffusion via connexons
Longer range diffusion requires ATP
How many types of oligodendrocytes are there?
Four Types of Oligo’s
- Can integrate many levels
- Only acts horizontally
- goes between two layers
- looks a lot like schwann cells
Neurons get glucose out of the blood because they cannot make it themselves
What kind of glia transports the nutrients such as lactate to neurons of the CNS?
Oligos transport lactate to axons
________ modulate synaptic transmission
Schwann Cells modulate synaptic transmission
Perisynaptic Schwann Cells can modify the post synaptic response at the NMJ (PSCs do not myelinate, they only modulate activity)
Schwann cells have direct control of synaptic activity
What kind of Schwann cells do not function as myelinating agents but rather modulate synaptic activity?
Perisynaptic Schwann cells can modify the post-synaptic response at the NMJ
PSCs are non-myelinating
Communication between nodal glia and axons at the nodes of Ranvier is essential:
- ________ glia maintain proper axonal function at the nodes of Ranvier
- They dictate ____
Paranodal glia maintain proper axonal function at the nodes of Ranvier
They dictate the molecular organization at the axon for normal function; this is lost in demyelinating disease
What kind of cells provide a type of anchor at the nodes of Ranvier for ion channels and other important things?
Paranodal glia
They express proteins to anchor and attract ion channels at the ndoes of ranvier
Most brain tumors are neoplasms of ___ cells
Most brain tumors are neoplasms of glial cells
(glioblastomas, schwannomas, astrocytomas)
What is the most severe kind of brain tumor?
Most severe brain tumor is glioblastoma multiforme
death occurs within a year of diagnosis
What is the most abundant type of brain tumor?
Meningiomas are the most abundant type of brain tumor
They are tumors of non-glial cells (arachnoid) or pituitary adenomas
What kind of tumor is a pituitary adenoma and what does it look like?
Pituitary adenoma is a type of meningioma
Schwannomas occur _________
Also called _____
Schwannomas occur at the root of the cranial nerve innervating the inner ear: “acoustic neuromas”
They are relatively common and treatable
