Development-vonBartheld Flashcards Preview

Block 5; Week 4 > Development-vonBartheld > Flashcards

Flashcards in Development-vonBartheld Deck (93)
Loading flashcards...
1

What is the sequence of neural development?

neural induction-->
neural tube formation-->
generation of neurons & glia-->
axon growth from neurons-->
synapses made with targets-->
dendrite growth-->
myelination

2

How do you get the 3 germ layers developmentally?

epiblast cells invaginate thru the primitive streak.
Then you get ectoderm, mesoderm, and endoderm

3

Describe the basic sequence of neurlation (neural tube formation).

ectoderm thickens in the middle & forms a neural plate
then you get a neural groove
the dorsal edges align & fuse-->get a neural tube!
Note: the neural tube first forms in the central part (from bird's eye view) & then zips caudally & rostrally.
Somites form on either side.
By day 23, caudal & cranial neuropores have formed.
By day 26, neurelation is complete.

4

What induces the ectoderm to become a neural plate?

this induction happens via the notochord underneath the ectoderm.

5

What is the equivalent of the notochord in amphibians? This was used in experiments to figure out the role of the notochord in neural plate induction.

the equivalent is the organizer in the dorsal region of the amphibians.

6

What does an organizer usu do in an amphibian?

generates axial mesoderm during normal development.

7

Who dated Hans Spemann?

von Bartheld's grandfather's sister. : )

8

What is the default fate of the ectoderm? What stops this?

Default: become neuronal
BMP4 inhibits this.

9

T/F In addition to BMP4, there are a large number of molecules that regulate different parts of the neural tube.

True.

10

T/F Different transcription factors code for different parts of the neural tubes.

True.

11

Where are neurons generated developmentally?

they are generated in the ventricular zone
the ventricular zone is made of the neuroepithelial layer that borders the neural tube.

12

When does neural tube closure happen? What is the clinical significance of this?

early 4th week
so a woman could be 22 days pregnant w/o even knowing it...then she could have the problem of teratogens affecting the neural formation of her baby.

13

What is spina bifida occulta?

this happens when the vertebral arches of the bone don't form properly.
happens in up to 5% of the population

14

What is a meningocele?

this happens with prolapse of the subarachnoid space
this can happen at the spinal or cranial level
even tho the neural tube is still intact, you need surgery.

15

What is a meningomyocele?

this is where the spinal cord is prolapsed into outer space, white matter may be protruding

16

What is rachischisis (no fold & fold)?

this is where you have no neural tube
the neural tissue that is overlying can be folded or not

17

What is a clinical sign of spina bifida occulta?

tufts of hair on lower back

18

What are 2 tragic neural tube defects that are not compatible with life?

cranial meningomyelocele
anencephaly

19

T/F Pts with anencephaly don't have any brain structures.

False. They don't have a telencephalon. They do have a brainstem, and thus can be born & live for several days.

20

What is the most common human malformation?

neural tube defects

21

What is the incidence of NTDs?

1-8/1000 live births
**incidence has been more recently reduced b/c of abortions after detection of NTD

22

What is the etiology of NTD?

failure of the neural tube to close

23

What is the cause of NTD?

multifactorial
could be chromosomal, diabetes, teratogens, hyperthermia

24

What types of meds should you NOT take if you are pregnant (capable of causing NTDs)?

epilepsy meds
acne meds (Vit A high)

25

What are some things that can help in detection of NTDs?

ultrasound (detects anencephaly especially)
alpha fetoprotein

26

What is something that helps in prevents of NTDs?

folic acid!
-this has a 72% reduction power in incidence of NTDs
now we have fortified flour w/ folic acid in it etc.
-prevents 30 - 50% of NTDs

27

What is a problem with fortifying our food supply with folic acid?

main issue is that if a pt has Vit B12 deficiency, the folate they are taking will mask the symptoms (hematologic disease) & will worsen the neurological symptoms

28

What are 3 classes of teratogens affecting neuronal development?

infectious agents
physical agents/temp
drugs

29

What are some of the infectious agent teratogens? What are their effects?

rubella-eye & ear defects
cytomegalovirus-eye defect, microcephaly
toxoplasmosis-hydrocephalus

30

Where do you find taxoplasmosis?

you find it in cat litter
it is a parasite