Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
WEEK 4:
embryology 4:
| Question | Answer |
|---|---|
| what happens by 8th day of development | blastocyst is partially embedded into endometrium |
| epiblast | ectoderm |
| hypoblast | endoderm |
| hypoblast layer consists of what type of cells | small cuboid cells adjacent to blastocyst cavity |
| epiblast layer consists of what type of cells | tall columnar cells on the trophoblastic side of the embryoblast |
| somatic mesoderm covers | amniotic cavity and forms the amnion |
| splanchnic mesoderm lines | trophoblast to form the chorion |
| rate at which cavities grow | amniotic cavity enlarges faster than the chorionic cavity and gradually obliterates it and eventually the amnion and chorion join and the fetus floats in the amniotic fluid |
| changes in day 13 | primitive yolk sac undergoes much reduction in size- where this reduced sac is lined by cells that migrate from hypoblast to form the secondary yolk sac and extraembryonic coelom transverses all of chorionic cavity except connectin stalk |
| umbilic cord is the | connecting stalk |
| chorion is made of | trophoblast and extra embryonic mesoderm |
| chorion eventually becomes | smooth at abembryonic plate (chorion leave) and irregular (chorion frondosum) at the embryonic pole where placenta is developing |
| decidua | modified endometrium of uterus during pregnancy |
| decidua basalis | located at site of implantation between embryo and myometrium forming the maternal part of placenta |
| decidua capsularis | thin layer that grows over embryo on luminal side enclosing it and connecting with decidua basalis |
| decidua parietalis | lines rest of uterine cavity and is NOT in contact with embryo |
| decidua capsularis eventually fuses with what | decidua parietalis |
| amniochorionic membrane made of | amnion and chorion |
| importance of syncytiotrophoblast | primary site of placental function eg nutrient and gas exchange, hormone production eg estrogen, progesterone and hCG |
| chorionic villi | finger like processes on outer surface of chorion - in relation to decidua basalis, these grow extensively (chorion frondosum) contributing to formation of fetal part of placenta |
| primary villi | trophoblastic cells form these |
| secondary villi | mesodermal cells penetrate the core of the primary villi to form these |
| tertiary villi | blood vessels develop in the mesoderm by end of third week forming these |
| when placental villi first form they are called | primary stem cell villi which have a core of cytotrophoblast covered by a layer of syncytiotrophoblast |
| secondary villi have developed a core of | extra embryonic mesoderm inside the 2 trophoblast layers |
| tertiary villi have developed what | fetal blood vessels within the mesodermal core |
| stem/ anchoring villi extend where | extend from chorionic plate to decidua basalis |
| free/ terminal villi are | lateral branches of stem villi |
| FETO-MATERNAL barrier initially consists of | 1. Syncytiotrophoblast 2. Cytotrophoblast 3. Mesoderm 4. Endothelium of fetal vessels (see tertiary stem villus cross section) |
| intervascular barrier | tissue layers BETWEEN maternal and fetal bloods |
| first trimester | few villi but large central few vessels (so exchange surfaces are small and distances large) |
| third trimester | villi are numerous and small with peripheral fetal vessels (so exchange surfaces are large and distances small) |
| first trimester barrier comprises of | layer of syncytiotrophoblast complete layer of cytotrophoblast substantial mesoderm endothelium of fetal vessels |
| third trimester barrier comprises of | synctiotropholast layer isolated cytotrophoblast cells little mesoderm endothelium of fetal vessels |
| at 9 months, maternal blood enters | cotyledons via 80-100 spiral aa |
| at 9 months, maternal blood leaves via | tributaries of uterine vv |
| maternal (intervillous) blood space surrounds | villous trees and holds about 150ml of blood |
| placental abruption/ abruptio placentae) | placenta peels away from uterine wall partially or almost completely before delivery which can deprive fetus of oxygen and nutrients leading to poor growth and bleeding in mother or even premature births/ stillbirth (1/100 pregnancies) |
| placenta praevia | low lying placenta covers part or all of opening of cervix which can block the baby's exit from uterus and blood vessels connecting abnormally placed placenta to uterus may tear leading to bleeding at labour and maybe premature birth (1/200 pregnancies) |
| placenta accreta | placenta implants too deeply/ firmly into uterine wall (increta/perceta= embed into uterine muscle) which may cause excessive bleeding at delivery (1/2500 delivaries) |
Created by:
kablooey
Popular Medical sets