2nd-3rd week of Development Flashcards
T or F
The first trimester of pregnancy is the most critical
TRUE
What week does this occur?
Bilaminar Germ Disc
o Focus is the embryoblast
o Bilaminar - embryoblast dividing into two layers
2nd Week of Development
T or F
In the 8 th day of development the mother already knows shes pregnanat
FALSE
Day 8
o Not yet know that mother is pregnant
Trophoblast Two Layers:
Cytotrophoblast
Syncitiotrophoblast
Embryoblast Two Layers
Hypoblast Layer
Epiblast Layer
- adjacent to amniotic cavity
Epiblast Layer
adjacent to blastocyst
cavity
Hypoblast Layer
outer, where cells
from cytotrophoblast migrate and fuse,
arrange and package
Syncitiotrophoblast
inner, where mitotic
figures are found. Mitosis, this is where your
cells abruptly divide
Cytotrophoblast
T or F
Epi means above; Hypo means below; Cavity
means space
TRUE
What day does this occur?
Epiblast give rise to amnioblasts that line the
amniotic cavity - it will produce its lining
DAY 9
What day does this occur?
Hypoblast cells will join with the exocoelomic
membrane to produce a lining surrounding the
primitive yolk sac
Day 9
T or F
Primitive Yolk Sac or Exocoelomic Cavity or
Heuser’s Membrane was the Blastocyst Cavity
TRUE
Day 10 is the
Day 10
● The rest day
When?
● Chorionic Cavity or Extraembryonic Cavity develops from the Primitive Yolk Sac
● Embryo is completely embedded into the uterus
Day 11 and 12
When?
Occurrence of bleeding at the implantation site as a result in increased blood flow into the lacunar
spaces
DAY 13
T or F
Lacunar Spaces are found in the
syncitiotrophoblast
TRUe
What produces cells that proliferate and form
new cavity within primary yolk sac known as
Secondary Yolk Sac
Hypoblast
T or F
Connecting stalk becomes the pancreatic duct with
blood vessels
FALSE
Connecting stalk becomes the umbilical cord with
blood vessels
the connection of mother and child occurs
Umbilical Chord
When?
This is when menstruation starts. Spotting is
mistakenly as menstruation
DAY 13
spots of blood, only little
amount and the next day it does not occur
Spotting
95% occurs in Fallopian Tube instead of the
uterus
Ectopic Pregnancy
Accounts to 9% of pregnancy related deaths due
to Internal Hemorrhage
Ectopic Pregnancy
T or F
Most ectopic pregnancies dies during the 7th
month, and the mother suffers from heavy
hemorrhaging
FALSE
Most ectopic pregnancies dies during the second
month, and the mother suffers from heavy
hemorrhaging
When is the Trilaminar Germ Disc present/ highlighted
3rd week of development
The process that establishes all the three germ
layers
Gastrulation
From Hypoblast to germ layers - Ectoderm,
Mesoderm, Endoderm
Gastrulation
Derivatives
- Endoderm - GIT, Lungs, and Liver
- Mesoderm - Muscle, Connective Tissue, and
Vascular System - Ectoderm - Entire Nervous System
- cells migrating through the mid-streak level
Intermediate Mesoderm
cells migrate through the caudal part of streak
Lateral Mesoderm
first cells traveling to the cephalic end, the head
Prechordal Plate
T or F
The talusus develops into the legs of the baby
FALSE
The caudal develops into the legs of the baby
eventually becomes the mouth opening
Oropharyngeal Membrane
- becomes the opening of the anus
Cloacal Membrane
Solid cells extending from primitive node to notochordal plate
Notochord
Any substance that could harm the embryo. In week
three, the mother is not yet sure if she is pregnant
Teratogens
The mother is prone to Teratogens if the mother is not
living healthy
Teratogens
Alcohol, caffeine, tobacco, drugs are examples of
Teratogens
Insufficient caudal mesoderm has resulted in
fusion of the – and birth defects
Caudal Dysgenesis or Sirenomelia
The differentiation of cells in the Caudal part is
not Completed
Caudal Dysgenesis or Sirenomelia
Genetic defect that caused transposition of the
viscera in the thorax and abdomen
Situs Inversus
Occur when cells of the primitive streak get left
behind in the sacrococcygeal region, and these
cells develop into tumors attached to its but and
feet
Sacrococcygeal Teratoma
More common in female fetuses
o The baby is not getting all the nutrients
Sacrococcygeal Teratoma
