Neurulation

Question 1

When does the epiblast migrate through the primitive streak

Answer 1

3 weeks

Question 2

What does the endoderm give rise to?

Answer 2

Epithelial linings of resp. tract and digestive system, GI glands and glandular cells of liver and pancreas

Question 3

What derivatives come from the mesoderm?

Answer 3

Skeletal muscles, blood cells, the lining of blood vessels, smooth muscle, trunk Ct, most of CV system, notochord

Question 4

What is the ectoderm derived from?

Answer 4

Epiblast

Question 5

What is the mesoderm derived from?

Answer 5

Epiblast that penetrated the primitive streak

Question 6

What are the derivatives of the ectoderm?

Answer 6

Epidermis of the skin, epidermal derivatives, CNS, PNS, neural crest cells, eyes, internal ears

Question 7

What is the notocord made of

Answer 7

Primitive pit and mesodermal cells

Question 8

What induces ectoderm to become the neural plate?

Answer 8

Notochord

Question 9

Surface ectoderm forms what?

Answer 9

Epidermis

Question 10

Neuroectoderm forms the

Answer 10

Neural plate and neural crest

Question 11

What is neurulation

Answer 11

The process by which the notochord, neural plate and neural crest become distinct

Question 12

What acts as a hinge for neurulation

Answer 12

Neural groove

Question 13

Where does the neural plate begin to fold

Answer 13

Lumbar area up

Question 14

What does the neural tube arise from

Answer 14

Mesenchyme

Question 15

What is the process of forming the neural tube called?

Answer 15

Secondary neurulation

Question 16

Where does secondary neurulation occur?

Answer 16

The level of the sacral vertebrae

Question 17

What do the mesoderm of the head and neck come from?

Answer 17

The neural crest

Question 18

Defects in the folding of the neural tube at S1 S2 S3 typically manifest as what

Answer 18

Congenital heart defect

Question 19

What is the most common closure deficiency

Answer 19

Congenital heart issues

Question 20

Goldenhar syndrome is characterized by what

Answer 20

A neurocristopathy where incomplete closure of the mouth and nose area, ocassionally causes the mouth to be shifted

Question 21

What is TCS

Answer 21

A neurocristopathy disorder which cases the face of a person to have sunken in eyes and a mouth that projects anteriorly

Question 22

What is hirschsprung disease

Answer 22

Neurocristopathy in which patients have megacolon

Question 23

What is craniosynostosis

Answer 23

Neurocristopathy in which patients have an anterior projecting forehead

Question 24

What is micrognathia

Answer 24

Neurocristopathy in which a jaw is small or lacking

Question 25

What is piebaldism

Answer 25

Neurocristopathy in which areas of melanocytes have no pigment

Question 26

What do the meninges develop from

Answer 26

Neural crest cells and mesenchyme

Question 27

When do the meninges migrate to surround the cns? What does this form?

Answer 27

20-35 days, primitive meninges

Question 28

What do the primitive meninges differentiate into

Answer 28

Ectomeninx and endomeninx around 34-48 days

Question 29

What happens between 45-60 days

Answer 29

Ectomeninx becomes more compact and forms spaces for future venous sinuses Endomeninx becomes more reticulated and suharachnoid space appears

Question 30

What dissociates giving rise to the epidural space

Answer 30

Spinal ectomeninx

Question 31

How does the neural tube close and what do they form

Answer 31

Initiated at 5 sites and goes in both directions; cranial and caudal neuropore

Question 32

What does a closure defect at closure 5 cause

Answer 32

Spina bifida

Question 33

What is a defect at closure 2

Answer 33

Anancephaly

Question 34

What is a defect at closure 1

Answer 34

Craniorachischisis

Question 35

What is encephalocele

Answer 35

When parts of the brain go into a sac behind the head

Question 36

What is meroencephaly

Answer 36

Acrania, from the lumbar portion up the spinal cord is open

Question 37

What is cranioachischisis

Answer 37

When the spinal cord is open from sacral region up

Question 38

What is spina bidfida oculta

Answer 38

When the neural arch doesn’t close completely These patients have a tuft of hair above this area

Question 39

What is meningocele

Answer 39

Where there is a sac filled with CSF extending from a portion of the spine

Question 40

What is meningomyelocele

Answer 40

Meningocele but with the spinal cord in that sac

Question 41

What is myeloschisis

Answer 41

Where the spinal cord is hemisected and open to the skin

Question 42

When does head and tail folding begin

Answer 42

Week 4

Question 43

What happens during the head fold

Answer 43

Neural folds project dorsally into the amniotic cavity Neural folds grow cranially into oropharyngeal membrane and overhang the primordial heart Forces translocation of septum transversum, primordial heart, peridcardial coelom to ventral surface

Question 44

What forms the future anus

Answer 44

Cloacal membrane

Question 45

When does the umbilical cord form?

Answer 45

After dorsal/ventral folding and lateral folding

Question 46

When does the abdominal wall fuse

Answer 46

Lateral folding

Question 47

What are some anterior body wall malformations

Answer 47

Omphalocele - bowel in membranous sac Gastroschisis - bowel is exposed and protruding through body wall Ectopia cordis - heart outside the rib cage

Question 48

What is the pentalogy of cantrell

Answer 48

``` Anterior body wall malformation Needs -midline abdominal defect -anterior diaphragmatic hernia -cleft strenum -pericardial defect -intercardiac defect ```