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Flashcards in implantation and early placentation Deck (29)
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1

what is gestational age

used clinically, from LMP to present. Expressed in terms of completed weeks plus days

2

when does implantation begin

day 6/7 after ovulation

3

what are the 3 stages of implantation

apposition, attachment, penetration

4

during apposition and adhesion of embryo what hormones are being released locally and what signalling occurs?

egf and lif signalling between embryo and endometrium

cox 2 surface epithelium
growth factors and cytokines from embryo and endometrium

estrogens and progesterones

complex interaction of all hormones allowing apposition and adhesion

5

with regards to menstrual cycle what phase can endometrium become receptive

secretory phase

6

outline the window in which the endometrium is receptive

on average day 7-10 of secretory phase

7

outline how endometrium can discriminate against embryos to prevent poor birth outcomes

if embryo is low quality likely to have defects, won't allow implantation, high quality and it will allow implantation, generally.

8

what are the two layers of the primitive placenta (trophoblast)

Inner layer is composed of mononuclear cells and is
known as the cytotrophoblastic layer.
• Outer layer consists of multinucleated cells and is
known as the syncytiotrophoblast.

9

what two changes chracterise haemochorial placentation

differentiation of endometrium into decidua

transformation and opening of uterine spiral ateries

10

when do chorionic villi appear

at the end of the second week in placenta development

11

where do the central core of cells in primary villious stems come from

derived by the proliferation of the cytotrophoblast.

12

how do primary villi develop to secondary villi

they get mesoderm cores

13

how do secondary villi become tertiary

tertiary villus are characterized by villous capillaries developing

14

how do you get chorion leavae

As the growth continues, the villi on the decidua
capsularis (abembryonic) pole degenerate

15

how do you form chorion frondosum

Villi adjacent to the decidual plate rapidly grow and
expand

16

what impact does a spiral atery narrowed in a segment cause

placental villious tree has fewer branches because of blood flow chracteristics resulting in reduced fetal growth and pre eclampsia

17

by what month has the placenta achieved it's defined form and undergoes no anatomical modifications

4 month of pregnancy

18

what forms the maternal portion of placenta

decidual plate

19

what forms the fetal portion of placenta

the chorion frondosum.

20

what is chorionicity

numbver of gestation sacs

21

what is gastrulation

Formation of 3 germ layers
ectoderm mesoderm endoderm

22

what does endoderm give rise to

epithelial lining GI & respiratory tracts & bladder.
liver, pancreas, thyroid, tonsils, auditory epithelium

23

what does mesoderm give rise to

connective tissue, musculoskeletal system,
gonads, kidneys, spleen, cardiovascular system,
lymphatics

24

what does ectoderm give rise to

epidermis, hair, nails, nervous system
mammary glands, enamel of teeth,
neural crest cells: melanocytes, branchial arches,
meninges, adrenal glands, autonomic NS

25

when does neurulation occur

early on 4 embryonic week

26

state neural tube defects

spina bifida, ancephaly,

27

what is holoprosencephaly, and what are its effects

Failure of forebrain to divide & develop
• Associated with other midline & facial defects, Tri 13
• Severity varies from not being compatible with life to more
mild mental retardation

28

when does cardiogenesis occur

d18-d22

29

in cardiogenesis how are heart tubes formed

Canalization of cardiogenic
clusters in the mesoderm
results in the formation of the
paired heart tubes