ANAT2341: Week 1 and 2 - Embryology€¦ · ANAT2341: Week 1 and 2 Dr Annemiek Beverdam –School...
Transcript of ANAT2341: Week 1 and 2 - Embryology€¦ · ANAT2341: Week 1 and 2 Dr Annemiek Beverdam –School...
ANAT2341: Week 1 and 2
Dr Annemiek Beverdam – School of Medical Sciences, UNSW Wallace Wurth Building Room 234 – [email protected]
Resources ANAT2341:http://php.med.unsw.edu.au/embryology/
Larsen’s Human EmbryologyThe Developing Human: Clinically Oriented Embryology
Week 1/2 Lecture overview
Dr Annemiek Beverdam – School of Medical Sciences, UNSW Wallace Wurth Building Room 234 – [email protected]
Resources:http://php.med.unsw.edu.au/embryology/
Larsen’s Human EmbryologyThe Developing Human: Clinically Oriented Embryology
Fertilization
Cleavage stages
Morula formation
Blastocyst formation
Implantation
Generation of bilaminar embryo and matyernal decidua
Endometriosis
Twinning
Week 1
Week 2
Week 1/2
Fertilization/Zygote formation
Spermatozoa Sperm Binding (SED1/ZP3)
Acrosome Reaction Membrane Fusion
OocyteMembrane Depolarization
Cortical Reaction Meiosis II
Zygote FormationDiploid cell
Male and Female pronuclei First mitotic division within 24h
http://php.med.unsw.edu.au/embryology/images/c/c0/Fertilization_001.mp4
Cleavage stages - Day 1-5Blastomeres
No growth (G1/G2) stagesCompaction
Trophoblast/inner cell massSynchronous/asynchronous cell division
Blastocoel formation (Na+/K+ pump)Zona Pellucida
Fig 1-16 Larsen’s
Blastomere contacts and communicationTight and adherens junctions, and desmosomes: seal Gap junctions: communication
Hatching of the Blastocyst – Day 5
Fig 1-16 Larsen’s
Blastocyst hatching
Hatching (day 5)Multiple roles for zona pellucida
Ectopic pregnancies
http://php.med.unsw.edu.au/embryology/images/a/ae/Human_blastocyst_day_3-6.mp4
http://php.med.unsw.edu.au/embryology/images/b/b4/Week1_001.mp4
Week 1 of development
Fig 1-16 Larsen’s
Week 2: Implantation: Menstrual Cycle
hypothalamus:GnRH
Pituitary:LH - FSH
Endometrial growth
Follicle maturation
Estrogen
LH surge
Ovulation
Fertilization:
Corpus luteum
Progesterone(in response
to hCG)
Maintenance of endometrium
Nofertilization:
Corpus albicans
No Progesterone
Loss of endometrium
Implantation Menses
Week 1-2 Week 3-4
Week 2: Implantation: Uterus
Uterine wall consists of:- Endometrium (cycling)- Myometrium (parturition)- Perimetrium (tunica serosa)
Endometrium consists of:- Basilar zone (not lost, own blood supply)- Functional (spongy) zone, ovarian gland bodies,
cycles)- Compact zone: columnar epithelium, stromal
cells, ovarian gland necks: implantation
Week 2: Implantation: Endometrium
Endometrial receptivity window: 6-10 days after fertilization
Decidual reaction: Endometrial transformation (stroma)Spreads from implantation siteFacilitates implantation
Endometrial Receptivity
window
Decidual reaction
Week 2: Implantation: EmbryoDuring receptivity window of menstrual cycle
Adplantation: day 6-7 (Decidual reaction)Note orientation of blastocyst!
Implantation: days 8-9
Ectopic pregnancy
http://php.med.unsw.edu.au/embryology/images/a/a6/Week2_001.mp4
endometrialstroma
Adplantation Implantation
Week 2: Implantation: EmbryoTrophoblast: syncytiotrophoblast and cytotrophoblast
Inner cell mass: epiblast and hypoblast
Generation of bilaminar embryoAmniotic cavity and primary yolk sac
Start of placentation
Syncytiotrophoblast produces:Proteolytic enzymes
Human chorionic gonadotropin (hCG) hormone
http://php.med.unsw.edu.au/embryology/images/a/a6/Week2_001.mp4
endometrialstroma
Adplantation Implantation
Bilaminar Embryo and CavitationDay 10-13
http://php.med.unsw.edu.au/embryology/images/c/c1/Chorion_001.mp4
Bilaminar Embryo and CavitationDay 12-13
Extraembryonic mesoderm forms chorionic cavity (embryonic)Epiblast forms amniotic cavity (embryonic)
Blastocoel cavity becomes definitive yolk sac (embryonic) Endometrium forms the decidua (Maternal)
Bilaminar EmbryoDay 13-14
DeciduaDecidua Basalis: forms placenta
Decidua Capsularis: surrounds chorionic cavityDecidua Parietalis: rest of uterine mucosa
Endometriosis Ectopic endometrial tissue (ovaries, fallopian tubes)
Cycles in response to LH and progesterone
Twinning
Monozygotic twinning: identical genetic material
Type of monozygotic twin isdetermined by the timing of embryonic division:
A: 0-4 dpf: embryo splits in 2dichorionic, diamniotic
B: 4-8 dpf: ICM splits, distant embryoblastsMonochorionic, diamniotic
C: 8-12 dpf: ICM splits, Close embryoblastsMonochorionic, mono-amnionic
D: 8-12 dpf: ICM splits partiallyMonochorionic, mono-amnionicConjoined twins
ImplantationWeek 2
Week 1/2 Lecture overview
Dr Annemiek Beverdam – School of Medical Sciences, UNSW Wallace Wurth Building Room 234 – [email protected]
Resources:http://php.med.unsw.edu.au/embryology/
Larsen’s Human EmbryologyThe Developing Human: Clinically Oriented Embryology
Fertilization
Cleavage stages
Morula formation
Blastocyst formation
Implantation
Generation of bilaminar embryo and matyernal decidua
Endometriosis
Twinning
Week 1
Week 2
Labs Relevant to this Lecture
Preimplantion, early implantation and gastrulation (Lab 1)
Assisted Reproductive Technology (Lab 2)
Genetic modification of mice (Lab 4)