ANAT2341: Week 1 and 2

DrAnnemiekBeverdam– SchoolofMedicalSciences,UNSWWallaceWurth BuildingRoom234– A.Beverdam@unsw.edu.au

Resources ANAT2341:http://php.med.unsw.edu.au/embryology/

Larsen’s Human EmbryologyThe Developing Human: Clinically Oriented Embryology

Week 1/2 Lecture overview

DrAnnemiekBeverdam– SchoolofMedicalSciences,UNSWWallaceWurth BuildingRoom234– A.Beverdam@unsw.edu.au

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

Endometriosis

Twinning

Week 1

Week 2

Week 1/2

Fertilization/Zygote formation

Spermatozoa Sperm Binding (SED1)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

Zona Pellucida

Fig1-16Larsen’s

Blastomere contacts and communicationTightandadherens junctions:seal Gapjunctions:communication

Hatching of the Blastocyst – Day 5

Fig1-16Larsen’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

Fig1-16Larsen’s

Week 2: Implantation: Menstrual Cycle

hypothalamus:GnRH

Pituitary:LH- FSH

Endometrialgrowth

Folliclematuration

Estrogen

LHsurge

Ovulation

Fertilization:

Corpusluteum

Progesterone(inresponsetohCG)

Maintenanceofendometrium

Nofertilization:

Corpusalbicans

NoProgesterone

Lossofendometrium

Implantation Menses

Week1-2 Week3-4

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, overian gland necks: implantation

Week 2: Implantation: Embryo

During receptivity window of menstrual cycleAdplantation: day 6-7Implantation: days 8-9

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

Syncytiotrophoblast produces:Proteolytic enzymes

Human chorionic gonadotropin hormone

http://php.med.unsw.edu.au/embryology/images/a/a6/Week2_001.mp4

endometrialstroma

Adplantation Implantation

Bilaminar EmbryoDay 10-13

http://php.med.unsw.edu.au/embryology/images/c/c1/Chorion_001.mp4

Bilaminar EmbryoDay 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

EndometriosisEctopicendometrialtissue(ovaries,fallopiantubes)

CyclesinresponsetoLHandprogesterone

Twinning

Monozygotictwinning:identicalgeneticmaterial

Typeofmonozygotictwinisdeterminedbythetimingofembryonicdivision:

A:0-4dpf:embryosplitsin2dichorionic,diamniotic

B:4-8dpf:ICMsplits,distantembryoblastsMonochorionic,diamniotic

C:8-12dpf:ICMsplits,CloseembryoblastsMonochorionic,monamnionic

D:8-12dpf:ICMsplitspartiallyMonochorionic,monamnionicConjoinedtwins

ImplantationWeek 2

Week 1/2 Lecture overview

DrAnnemiekBeverdam– SchoolofMedicalSciences,UNSWWallaceWurth BuildingRoom234– A.Beverdam@unsw.edu.au

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

Endometriosis

Twinning

Week 1

Week 2

Labs Relevant to this Lecture

Assisted Reproductive Technology (Lab 1)

Genetic modification of mice (Lab 2)

Preimplanation and early implantation (Lab 3)

The Reproductive Technology Revolution (Lab 4)