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Flashcards in Development Deck (92)
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1

what controls limb development after the initial budding of the mesoderm

ectodermal ridge

1

what does thalidomide cause

amelia and meromelia

1

failure to retract seal the abdominal wall after retraction of the gut is called

umbilical hernia

2

apart from the bladder and urethra, the rest of the urogenital tract is formed from the..

intermediate mesoderm

3

when does the blastocyst implant into the uterine wall

between 5-10 days

3

what is the commonest congenital heart defect

ventricular septal defect

3

what causes sinus invertus

complete failure of the cilia of the primitive node - pure change whether organs are set properly or back to front

4

what is the neural crest

the cells at the point of fusion of the neural tube

4

what is the yolk stalk

that part of the yolk sac that is still connected to the gut lumen that persists until it is finally pinched shut

4

what happens to the urorectal septum

it extends towards the cloacal membrane to divide the rectum from the urogenital tract

5

order of endoderm, ectoderm and mesoderm from top to bottom of the blastocoele

ectoderm mesoderm endoderm

6

two cell populations in the blastocyst

inner cell mass

trophoblast

8

what structural feature determines morula from blastocyst

blastocyst undergoes cavitation to form a cavity = blastocoele

9

what is the morula

16 cell stage of the embryo

10

what is the cause of congenital hip dislocation

the acetabulum is malformed

- can be due to genetic or mechanical problems in utero

11

fate of the neural crest?

cells migrate off and leave the neural tube to form elements of the nervous system that dont form the CNS, and the other random things

12

what happens to the inner cell mass

- first splits into epiblast and hypoblast

- then epiblast will splits into 3 layers - ectoderm, endoderm and mesoderm

12

what lies between the allantois and the hind gut

urorectal septum (part of the mesoderm)

14

how many live births have a birth defect

1:33

14

how do the trachea, lungs, liver and pancreas initially appear

as endodermal out-pocketings interacting with the mesoderm

15

how many pharyngeal arches are there

4

16

what is amelia and meromelia

amelia - absent limbs

meromelia - reduced limbs

16

how is the gut tube made

yolk sac separates from the embryo --> due to this some of the endoderm is pinched off

17

which tissues does the intermediate mesoderm give rise to

urogenital system

17

where does the heart develop from

the lateral splanchnic mesoderm

17

what causes VSD

when the intraventricular foramen is not filled by membranous part of IVS

18

what are somitomeres

swellings of the flat sheet of paraxial mesoderm lateral to the neural tube on both sides

19

components of the mesonephros

pronephric duct of the pronephros becomes the mesonephris duct with mesonephric tubules

20

what is the zygote

the single fertilized egg

20

how does the large intestine get to the right position in the body

it is pulled there by the rotation and lengethening of the small intestine