22 - Applied Embryology Flashcards
what happens during day 1 of early embryo development?
formation of pronuclei
what happens during day 2 of early embryo development?
first cell division
what happens during day 3 of early embryo development?
cell division continues
what happens during day 4 of early embryo development?
formation of morula
what happens during day 5 of early embryo development?
blastocyst forms
4 components of the mature placenta?
Chorionic villi
The intervillous space
Placental Septae
Cotyledons
name 5 functions of the placenta?
Acts as an immunological barrier
Gas exchange
Nutrient exchange
Waste excretion
Endocrine functions
when does the mesoderm form?
day 12
when does the mesoderm spreading occur?
day 18
when does the amniotic sac enlargement occur?
day 23
where does the primitive streak develop?
caudal end of the embryo
what form the endoderm?
epiblast cells migrating into the hypoblast layer
how is the mesoderm formed?
epiblast cells migrate thought the primitive streak between the epiblast and hypoblast
where does the notochord develop?
develops cranially from just above the primitive streak
what are the two small areas at either end of the embryo without any mesoderm?
buccopharyngeal membrane
cloacal membrane
name 4 cell lines who are formed from ectoderm?
Epidermis
central nervous system
peripheral nervous system
hair
name 4 cell lines who are formed from mesoderm?
Dermis
musculoskeletal structures
cardiovascular system
gonads
name 4 cell lines who are formed from endoderm?
Lining of the gastrointestinal tract
the parenchyma of the liver
pancreas
thyroid
what is a neural plate?
thickening of ectoderm over the notochord
what does the neural plate become as it thickens?
neural groove
what do neural crest cells contribute to?
PNS
3 subunits of the mesoderm?
Paraxial Mesoderm
Intermidiate Mesoderm
Lateral Plate Mesoderm
what does the paraxial mesoderm form?
somites
what are the 2 subunits of the somites?
dermomyotomes
sclerotomes
how many occipital somites are there?
4
how many cervical somites are there?
8
how many thoracic somites are there?
12
how many lumbar somites are there?
5
how many sacral somites are there?
5
how many coccygeal somites are there?
8-10
what 3 structures does the intermediate mesoderm give rise to?
kidneys
ureters
gonads
what 5 structures does the lateral plate mesoderm give rise to?
pleura
pericardium
peritoneum
cardiovascular system
connective tissues & smooth muscle of GI and resp systems
during what week does the following occur -
Pharangeal Arches form
Neural tube is fusing, initial structures of the brain form
Upper limb buds, then lower limb buds form
The heart begins to beat
The primordial gut is forming
The beginnings of the lower respiratory tract forms
4
during what week does the following occur -
Upper limbs are divided into definite regions
Digital rays are forming
External Ear is forming
Some movements visible
6
during what week does the following occur -
The fingers begin to separate
The gut herniates into the umbilical cord
7
during what week does the following occur -
Fingers are separated but webbed
Toes are beginning to separate
The head is significantly larger
The eye is pigmented
8
when does the embryonic phase end and so foetal period begin?
beyond week 8
what is the incidence of natural multiple pregnancies in UK?
1:80
what is the difference in cause of non-identical twins and identical twins?
non-identical - multiple eggs fertilising and implanting
identical - embryo splits
what are the three stages of the development of the kidney?
The pronephros (non-functional)
The mesonephros (functional but transient)
The metanephros (final kidney)
what is the cloaca and what divides it?
caudal end of the enfolded yolk sac - divided by the urorectal septum
what does the divided cloaca form?
The urogenital sinus
The anal canal
what structure goes on to form the bladder and urethra?
urogenital sinus
which chromosome contains the SRY gene?
Y
what are the 2 sets of genital tracts?
Mesonephric Duct
Paramesonephric Duct
what determines which genital tract develops and which regresses?
presence or absence of AMH (Anti-Mullerian hormone)
what does presence of AMH cause in the male?
paramesonephric ducts regress
which association can often be made with women who have reproductive tract anomalies?
renal tract anomalies
what classification is used for congenital defects in female reprodcutive tract?
ASRM
