L1 Andre

Question 1

fertilisation occurs in which region of Fallopian tube ?

Answer 1

ampullary

Question 2

whats cleavage ?

Answer 2

mitotic divisions resulting in increase of cells

cells = blastomeres

Question 3

how is the inner cell mas formed ?

Answer 3

compaction

Question 4

how many cells in the morula ?

Answer 4

16

Question 5

inner cell mass will form ?

Answer 5

embryo

Question 6

outer cell mass will form ?

Answer 6

trophoblast

Question 7

Implantation begins around day ?

finishes ?

Answer 7

day 6

day 9

Question 8

what is zona pellucida

Answer 8

glycoprotein coat

Question 9

two components of trophoblast ?

Answer 9

cytotrophoblast (inner)

syncytiotrophoblast (outer)

Question 10

inner cell mass called ?

Answer 10

embryoblast

Question 11

embryoblast divides into ?

Answer 11

epiblast - columnar

hypoblast - cuboidal

Question 12

cavity in epiblast ?

Answer 12

amniotic cavity

Question 13

DAY 14

Answer 13

2 embryonic germ layers
2 cavities
2 components of trophoblast

Question 14

2 embryonic cavities ?

Answer 14

amniotic and yolk sac

Question 15

symmetric cell divisions at 8 cell stage …

Answer 15

2 identical daughter cells divide to give trophoblast external cells

Question 16

first asymmetric cell division ….

Answer 16

trophoblast still being formed
internal cells either become - bipotent cells or epiblasts
if they express FGF4 (epiblasts) pushing others to become hypoblast
if they express nanog = epiblast

Question 17

other waves of asymmetric division generates mostly ?

Answer 17

hypoblasts which have changes in adhesion and motility
during cavitation they migrate to inferior surface of inner cell mass to form thin epithelium
hypoblast express - SOX17 and GATA 6

Question 18

Cavitation is

Answer 18

formation of the blasocyst cavity

Question 19

Once the primitive endoderm (hypoblast) is formed …

Answer 19

cells expressing GATA6 and SOX17 that havent moved to inferior surface die

nanog expressing cells from epithelium superiorly

basal mem is formed between to layers

Question 20

Continued expression of FGF4 insures

Answer 20

continued expression of GATA6 and SOX17 for hypoblast differentiation

and inhibit nanog (epiblast factor)

Question 21

anterior visceral endoderm first secretes secretes ?

and function ?

Answer 21

DKK1 which inhibits Wnt

Question 22

Once fully formed the AVE secretes which 2 factors ?
effect ?
establishes ?

Answer 22

CER1 and LEFTY which inhibit nodal anteriorly
induction of cranial structures
establishes cranial end of embryo before gasturlation

Question 23

wnt 3 is expressed where ?

what does it induce ?

Answer 23

epiblast layer posteriorly which induces nodal posteriorly

Question 24

What effect does nodal have ?

Answer 24

stimulates the formation of the primitive node

Question 25

what day does gasturaltion begin ?

Answer 25

DAY 15

Question 26

What is gasturlation ?

Answer 26

process by which the definitive germ layers and axial orientation are established

Question 27

Where and how is the prim streak formed ?

Answer 27

the posterior midline of the epiblast | epiblast cells proliferate and migrate

Question 28

what does the prim streak establish?

Answer 28

L/R asymmetry

Question 29

The proliferation of epiclast causes the formation of depression ?

Answer 29

groove and pit

Question 30

Gasturaltion DAY 16 what happens ?

Answer 30

epithelial to meschemymal transition Meschemymal to epithelial transition population of the space between the difin ecto and endo to form defin mesoderm

Question 31

EMT is ?

Answer 31

epiblast around prim streak cells proliferate loose adherence, change shape and ingress

Question 32

MET is ?

Answer 32

2 waves of ingression as prim streak extends along midline - displacement of prim endoderm forms definitive embryonic endoderm

Question 33

what does remaining epiblast become ?

Answer 33

definitive embryonic ectoderm

Question 34

3 Types of mesoderm

Answer 34

Lateral plate mesoderm Paraxial mesoderm intermediate mesoderm

Question 35

How is prechordal plate formed ?

Answer 35

ingression through the cranial part of the prim node

Question 36

What is the prechordal plate

Answer 36

signalling centre for development of head and forebrain - head mesenchyme

Question 37

How is the notochord formed ?

Answer 37

ingression through prim node | NB signalling centre