GENERAL EMBRYOLOGY
13.02.2023 Anna Mac Gillavry Danylevska
FERTILIZATION
Zygote
– 18 h after fertilization 24 h 45 h
72 h Morula – 96 h
Blastocyst
CLEAVAGE AND IMPLANTATION
cleavage
Mitotic spindle
within zygote
Polar bodies
MORULA
BLASTOCYST
Syncytiotrophoblast
Primitive chorionic cavity
Embryonic pole
ENDOMETRIUM
UTERINE GLANDS
Trophoblast
Embryoblast
Extraembr.
mesoderm
Primitive
yolk sac
Chorion
Operculum
Amniotic cavity
Trophoblastic
lacunae
Cytotrophoblast
Endoderm
Ektoderm
Connecting stalk
Amnion
Germ disc
Definitive
yolk sac
Extraembryonic
coelom
IMPLANTATION – DAY 7
Trophoblast
Blastocyst
cavity
Hypoblast
Uterine epithelium
Syncytiotrophoblast
Epiblast
Blood capillary Uterine gland
Uterine gland
IMPLANTATION – DAY 8 1/2
Trophoblast
Blastocyst cavity
Hypoblast
Cytotrophoblast
Amniotic sac
Syncytiotrophoblast
Uterine gland
Trophoblastic lacune
IMPLANTATION – DAY 10
Primitive (primary) yolk sac Extraembryonic mesoderm
Hypoblast
Epiblast
Cytotrophoblast
Syncytiotrophoblast
Trophoblastic Amniotic Primary chorionic
lacune cavity villus
IMPLANTATION – DAY 13
Extraembryonic Definitive (secondary)
coelom yolk sac
Secondary
chorionic villus
Hypoblast
Epiblast
Cytotrophoblast
Syncytiotrophoblast
Connecting stalk Trophoblastic lacune
(extraembryonic mesoderm) (with capillary outlet)
DORSAL SIDE OF GERM DISC – DAY 14
Wall of amniotic cavity Oropharyngeal membrane
Connecting stalk
Wall of yolk sac
Hypoblast Epiblast
Primitive
streak
GERM DISC - DAY 16
GERM DISC - DAY 17
DIFFERENTIATION OF MESODERM
Somite Sclerotome
Nephrotome
Paired
aorta
dorsalis
Aorta dorsalis
Primitive gut
Aorta dorsalis
Dermatome
Myotome
Basis of arcus vertebrae
Basis of corpus vertebrae
paraxial
MESODERM intermediate
lateral
Splanchnopleura
Somatopleura