Human Embryogenesis Flashcards Preview

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Flashcards in Human Embryogenesis Deck (29)
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1
Q

when does oocyte get stalled

A

second meiotic division

2
Q

Capactiation

A

head of sperm can release enzymes

  • occurs in uterus/uterine tube
  • 6 hours of exposure
3
Q

acrosome reaction

A

allows sperm to petite corona radiate and zone pellucida

-degrades zona poluza to allow 1 sperm to fuse to PM of oocyte

4
Q

sperm fuse with oocyte

A

causes Ca concentration increase (diffuses into oocyte)

-causes corticol reaction

5
Q

Corticol reacion

A

vesicles in presynaptic membrane to fuse in

corticol granulas cause changes in zona pellucida preventing polymspermia-ensure no multiple sperm

6
Q

when does oocyte complete 2nd meiotic division

A

when sperm extrudes contents into oocyte (nuclei,s centrosome and mts)
-ALL OTEHR ORGANELLES ARE FROM MOM

7
Q

When does zygotic trx occur

A

3 weeks, all else occurs with maternal mRNA

8
Q

when does fist mitotic division occur

A

response to sperm fusing to oocyte

9
Q

what space do first several mitotic division occur+ how do they differ

A

inside zone pellucid-they are also identical

10
Q

Ectopic preganacy

A

implantation in any place other that uterun

11
Q

uterine tube terminates in

A

ampulla-most common place of ectopic reg

fimbrae-caress ovary
=open up into GI tract-peritoneal cavity

12
Q

Placenta forming on cervix

A

many problems-eventually gets torn

13
Q

What causes uterine lining changes

A

placenta formation

14
Q

where are two common sites of ectopic preg

A

ampulla of uterine tube

recouterine ch-most common peritoneal cavity place

15
Q

blastocyst strcutre

A

inner cell mass-embryoblast and trophoblast

  • embryoblast becomes embryo
    • aka embryonic stem cells
  • trophoblast becomes placenta
16
Q

how does trophoblast become placenta

A

becomes huge cell with many nuceli-syncitio
-produces and releases HCG (hormone)
0HCG levels rise at implantation
-hormione reg tests look for rise in HCG

17
Q

syncytiotrophoblast

A

produces HCG

invades uterine lining and induces vascular changes

18
Q

what happens when synctioblast invades

A

embroblast differentiates into epiblast and hypoblast

-epiblast is more dorsal (posterior)

19
Q

cytotrophoblast

A

no nutrients-get nutrients from maternal fluid

  • primitive yolk sac
  • eventually biomes primary villi
20
Q

Lacunae

A

formed from syncytiotrohphoblast

  • hollow spaces
  • fill with blood
21
Q

Epiblast vs hypoblast + wjere adjere

A

cell layers in developing embryo

epiblast-posterior/dorsal-aminiotic caivty is more dorsal than epiblast

hypobast-anterior+ventral

adjere at buccopharyngeal (cranial) and cloacal (caudal) membrane
-WHEN embryo TRX BEINGS

22
Q

Primitive yolk sac

A

from cytotrphoblast

dives in tear drop formation into secondary yolk sac (suspended from connecting yolk sac)

and cyst(which develop ointo microvilli_

23
Q

4th week

A

zygotic trx beings

gastrulation starts

primitive streak appears at caudal end of dorsal surface of epiblast

all sides defined

Now called an embryo

24
Q

Primitive node

A

appears at cranial end of primitive streak

Cells here have single, solitary, motile cilia

Fluid here has SHH-sets up assymetry

25
Q

Motile cilia in primitive node

A

move right to left

  • move vesicles and release thier contents (shh)
  • cuases gene expresión changues on left vs right
26
Q

Sidus inversus

A

everything reverses-cilia beat other way

27
Q

Defects in cilia at promitive node

A

no assymetry-many problems such as deafness, sids inverses, death, kidney diseases

28
Q

Fate of primitive streak cells

A

delaminate-migrate between epiblast and hypoblast-establish mesoderm

Some cells will invade hypblast and replace it to establish endoderm

All epiblast will become ectoderm
-wil not invdade buccopharyngeal or cloacal membrane

29
Q

Fate of epiblast cells in primitive node

A

delaminate and establish middling notochord between endoderm cranial to primitive streak