Term
|
Definition
| process that converts a flat neural plate into a cylinder, and moves it inside the body. |
|
|
Term
| what are the cellular processes involved in neurulation |
|
Definition
| thickening of neural folds, elvations of neural folds, fusion, delamination and migration of the neural crest. |
|
|
Term
| at what day does neural tube closure commence? |
|
Definition
| Neural plate forms at about day 19 and at day 20 the neural tube begins to close at the cervicle levels. |
|
|
Term
| neurulation progresses roughly in what direction? |
|
Definition
|
|
Term
| What are the intrinsic forces involved in neurulation? |
|
Definition
| cell elongation, cell wedging (apical constriction) changes in cell-cell adhesion, cell rearangement and cell division. |
|
|
Term
| What are the extrinsic forces involved in neurulation? (forces generated outside the neural plate? |
|
Definition
| flattening, cell divisioin, and rearrangement. |
|
|
Term
| what are the final areas of the tube to close/fuse? |
|
Definition
| extreme cranial and extreme caudal ends. ...they remain unfused until day 25 when the cranial neuropore closes and at day 27 the caudal neuropore closes. |
|
|
Term
| What are the two main categories of neural tube defects? |
|
Definition
| spina bifida, and anencephaly. |
|
|
Term
|
Definition
|
|
Term
| what is spina bifida occulta? |
|
Definition
| "hidden" spina bifida.... (10% of pop. has this) asymptomatic... |
|
|
Term
| what is spinda bifida operta? |
|
Definition
| this is more serious, it includes the neural tube and/or meninges.... |
|
|
Term
| what are the three types of spina bifida operta: |
|
Definition
| meningocele, meningomyelocele, and myeloschisis. |
|
|
Term
|
Definition
| protruding sac of csf filled meninges |
|
|
Term
| what is meningomyelocele? |
|
Definition
| protruding sac of csf filled meninges + spinal cord. |
|
|
Term
|
Definition
| when the open neural tube protrudes through the skin! failure of neural groove closure! |
|
|
Term
| what is chiari malformation? |
|
Definition
| when the cerebellum and brain stem herniate through the foramen magnum of the skull. (usually results in blockage of csf flow from the fourth ventricle to the subarachnoid space=hydrocephalus. |
|
|
Term
|
Definition
| when neurulation fails to occur within the brain region leaving the neural plate exposed to the surface, the tissue then degenerates. typically in anencephaly the only portion of brain that remains is the brain stem. |
|
|
Term
| by how much does folic acid reduce the incidence of neural tube defects? |
|
Definition
| by one half or 2/3. (neurulation occurs at 3-4 weeks of gestation, before woman usually even knows she is pregnant! |
|
|
Term
| What is secondary neurulation? |
|
Definition
| neurulation in the caudal region, where tial bud mesoderm forms the neural tube and somites. |
|
|
Term
| the will be neural tissue forms what here ... it will eventualy cavitate to form the lumen of the neural tube |
|
Definition
|
|
Term
| where on the vert. column does this juction b/w primary and secondary neurulation occur?> |
|
Definition
|
|
Term
| describe elongation of the neural plate? |
|
Definition
| the plate changes shape dramatically during neurulation. goes from keyhole shape to highly elaborated brain structure and elongated spinal cord. |
|
|
Term
| what are the changes in neural tissue proportions due to intially? |
|
Definition
| convergent extension movements, oriented cell division that elongates the cranial caudal axis (esp. in spinal regions) |
|
|
Term
| where do neural crest cells arise and reside prior to migration? |
|
Definition
| they arise in the lateral margins of the neural plate and therefore reside on the dorsal neural tube at the end of neurulation. |
|
|
Term
| discuss neural crest migration? |
|
Definition
| neural crest cells undergo emt and migrate to diverse locations in the embryo, occurs in a characteristic cranial to caudal migratory pattern. |
|
|
Term
| what are some of the derivatives that n.c. cells give rise to? |
|
Definition
| peripheral neurons, cart., bone, c.t.,adrenal cells, pigment cells, smooth muscle, multiple minor tissue types. (basically you name it and n. c. cells probably had some role them) |
|
|
Term
| what is the name for birth defects from defects in neural crest migration? |
|
Definition
|
|
Term
| name some examples of neurocristophathies? |
|
Definition
| waardenburg syndrome, hirschprung disease, treacher collins syndrome, digeorge syndrome. |
|
|
Term
| what does the signal molecule BMP4 do in terms of neural tissue formation? |
|
Definition
| it inhibits formation of neural tissue. |
|
|
Term
| ectoderm cultured as in tact epithelium they make what? |
|
Definition
|
|
Term
| when seperated they made what? what does this mean? |
|
Definition
| when seperated they make neurons, this tells us that an inhibitory signal generated in the intact epithelium inhibits neural tissue formation. |
|
|
Term
| so what does the notochord do in order to counter the BMP4 signal coming from the ectoderm? |
|
Definition
| it secretes BMP binding molecules chordin, follistatin, and noggin. they supress the supressor and allow neural tissue formation. |
|
|
Term
| d/v patterning and cranial caudal patterning? |
|
Definition
| go over the last pg. of this section in the syllabus better ... its easy but needs refressing....pg. 37 |
|
|
Term
| what are the names of the birth defects causes from Shh signaling? |
|
Definition
Holoprosencephaly- cuased from reduced Shh signaling...
And smith-lemli-optiz syndrome-caused from a molecule binding and activivating Shh (so probably excess Shh is the problem here) |
|
|
