neurulation and neural crest

Question 1

How is the neural plate formed?

Answer 1

SHH (sonic hedge hog) is released and will signal cells in the ectoderm to differentiate. They will form the neural plate consisting of a neural groove, neural folds and neural crest.

Question 2

What the is the process of neurlation?

Answer 2

The cells from the neural plate will invaginate and loop together to form the neural tube. This is now separated from the surface ectoderm

Question 3

What happens to the neural crest?

Answer 3

They are not incorporated into the neural tube and will migrate from the neural tube to form other structures

Question 4

What is the rostral neuropore

Answer 4

.The upper opening of the neural tube

Question 5

What is the caudal neuropore

Answer 5

the lower opening of the neural tube

Question 6

What is primary neurulation?

Answer 6

The closure of the neural tube from the layers that will be the brain to the lumbar region

Question 7

What is secondary neurulation?

Answer 7

The closure of the neural tube from the layers that will be the coccyx and sacrum

Question 8

What is the process of neurulation?

Answer 8

Around the area of the 4th or 5th somite, the tube will close and then zipper close spreading from the site to the caudal or rostral regions

Question 9

What days does the process of neurulation occur?

Answer 9

around day 25(rostral) and day 28(caudal)

Question 10

What does the neural crest give rise to?

Answer 10

sensory neurons of the peripheral nervous system, spinal ganglia, dura/pis mater, chromatin cells, walls of large arteries, bone/cartilage of face and the teeth

Question 11

What are some diseases that arise from the neural crest problems?

Answer 11

Hirschsprung’s disease, aorticopulmonary separation, cleft lip, Digeorge syndrome and dental abnormalities

Question 12

What are some neural cord defects from the spinal cord?

Answer 12

spinal bifida occulta, meningocele, meningomyelocele and myelocele

Question 13

What is a spinal bifida occulta?

Answer 13

failure of the caudal end of the neural tube to close- small non closure of the vertebral arch- there will be a small tuft of hair and the base of the spine

Question 14

What is meningocele?

Answer 14

a defect in the closure of the caudal end of the neural tube- results in a collection of CSF beneath the skin where the cord is open- there is no cord present in the defect

Question 15

What is meningomyelocele?

Answer 15

A defect in the closure of the caudal end of the neural tube- results in the a cyst covered will a meninges and spinal cord present in the defect. These patients will have sensory/mental defects

Question 16

What is myelocele?

Answer 16

The spinal cord is completely open and exposed to the environment.

Question 17

How are neural tube defects detected during pregnancy>

Answer 17

elevated levels of alpha feta protein in made by the fetus

Question 18

What do pregnant women take to lower the risk of spina bifida?

Answer 18

folate

Question 19

What are some cranial neural tube defects?

Answer 19

anencephaly, encephalocele

Question 20

What is anencephaly?

Answer 20

a neural tube defect from the rostral neuropore that results in the missing of the neural cortex

Question 21

What is encephalocele?

Answer 21

a neural tube defect from the rostral neuropore that results in a cyst formation that can contain brain material

Question 22

What is the meninx primitiva and what tissue is it derived from?

Answer 22

It will be the meninges- develops from the sclerotome and the neural crest

Question 23

What are the two types of meninx primitiva and what are they derived from?

Answer 23

The pachymeninx which will be the dura mater- mesoderm

The leptomeninges which will be the pia and arachnoid mater- derived from the neural crest