Term
| Give the three primary vesicles formed by the neural tube and then the secondary vesicles they derive? |
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Definition
Forebrain (prosencephalon)
-Telencephalon
-Diencephalon
Midbrain
-Mesencephalon
Hindbrain (rhombencephalon)
-Metencephalon
-Myelencephalon
-For the order it is; TD Mes Met Mye |
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Term
| Give the adult derivatives of the secondary vesicles and the ventricles in each? |
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Definition
Telencephalon; (Lateral ventricles)
-Cerebral hemispheres
-Most of basal ganglia
Diencephalon; (Third ventricle)
-Thalamus
-Pineal gland
-Neurohypophysis
-Hypothalamus
-Retina
Mesencephalon; (Cerebral aqueduct) [only one w/out vent]
-Midbrain
Metencephalon; (Fourth ventricle)
-Pons and cerebellum
Myelencephalon; (Fourth ventricle)
-Medulla |
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Term
| What is Rathke's pouch what problem can it cause? What is the other name for what it derives? |
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Definition
-It is the oral ectoderm derived pouch that gives rise to the anterior pituitary (adenohypophysis)
-Remnants of the pouch form craniopharyngiomas which can compress the optic chiasm
-These tumors arises from nests of odontogenic (tooth-forming) epithelium within the suprasellar/diencephalic region and, therefore, contains deposits of calcium |
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Term
| Describe axon transport? What is the clinical significance of the reverse type of flow? |
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Definition
-Because Nissl substance (RER) is only in the cell body, proteins and such need transported down the axon, which occurs in **anterograde flow
-Anterograde transport uses microtubules and *kinesin, and happens at about 400mm/day (or 1-3 for bulk flow)
-Retrograde flow (for recycling) uses microtubules and *dynein and is slower at 200mm/day
-Retrograde flow is how exogenous substances get to the cell body and cause harm (such as herpesvirus, polio virus, rabies, and tetanus toxin) |
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Term
| What happens when the flow isn't working right? What symptom is produced? What disease do we see this in? |
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Definition
-You get axonal polyneuropathy which produces a "glove and stocking" weakness
-Often seen in diabetics |
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Term
| What is the result of severing an axon? Which types can grow back? How? |
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Definition
-You get anterograde (Wallerian) and retrograde degeneration
-The anterograde degeneration is complete and does so all the way to the nerve ending
-The closer the lesion is to the cell body, the lower it's chances of survival
-Only axons in the PNS surrounded by Schwann cells have a chance of growing back because they form a tube to guide the growing axon to its destination
-This occurs at about 1-3mm/day, or at the same speed as bulk flow |
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Term
| What are the glial cells derived from neural tube? |
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Definition
-Ependymal cells; line the ventricles and have cilia on their luminal surfaces to move CSF
-Astrocytes; control microenvironment of CNS neurons, participate in the blood-brain barrier, are are the cells which proliferate in response to injury
-Oligodendrocytes; mylinate many axons in CNS (up to 50) |
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Term
| What are the other glial cells of the CNS? |
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Definition
| -Microglia are derived from mesoderm and are basically the macrophages of the CNS |
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Term
| When does myelination of the CNS begin and end? |
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Definition
| -Begins during month four and goes into teens |
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Term
| Note; check out page 334s brain diagram and practice. Also page 2 of neuronetter. |
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Definition
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