User talk:Z3462124

From Embryology

Artificial Reproductive Technologies (ART) Ass. Prof. Gilchrist--> womens health and IVF

Lab 2

  • IVF partnership between scientists and doctors -- management of patient and their needs as well as research in labs
  • Growing industry--> IVF and also research and technical sides
  • ~5 million IVF offspring living today--> arguably greatest medical success stories of our time = an emotional process for couples
  • AUstralia has and continues to be a pioneer in this areas

Just under a million couples each year. 1/6 Australian couples are treated for infertility--> in 2010 ~3.3% of babies were IVF. IVF hormones cost the PBS ~$100 million/year--> movement out of the private sector. Subsidized by Medicare (a large portion covered- particularly the drugs and ~six rounds of IVF) therefore it is not as expensive in aus.

Marriage of Science Research and Medicine;

Wolrds first IVF baby born in 1978-- Louise Brown-- very controversial- born in cambridge BOB EDWARDS won the Nobel Prize for Medicine for his role in the production of IVF technologies--- extremely controversial (unhealthy children)

Donor Sperm= 1960; poor quality/ no sperm

  • artificial insemination

Ovulation induction= 1960

  • failure of follicle to ovulate
  • One injection of hCG to induce ovulation

Donor Egg= no/ poor quality eggs -->1984

Pre-implantation genetic diagnosis= 1988

  • diagnosing genetic abnormalities
  • ability to remove cystic fibrosis (single gene following Mendilian ratio- very easy to detect) from a family--> are we removing evolution in a Darwinian sense?
  • Very controversial at the time
  • 10 embryos--> 5 are carriers; 2.5 are affected and 2.5 are unaffected
  • 1 blastomere (cell) is extracted and tested for the disease (once removed and tested the blastocyst is destroyed--- no huge implications for the embryo)
  • it is possible to sequence an entire genome from the one cell (predicting higher propencities for strokes or CVD -- Illegal in Australia)
  • process= Comparactive Genomic hybridisation)
  • eg's Aneuploidy, trisomy 21, translocations, single gene defects
  • in AUS only legal if the offspring will be affected by a devastating disease eg Trisomy 21 --> no sex selection, unless for a sex linked disease

Sperm Injection = 1992

  • instead of bathing egg in sperm
  • 70-80% of all IVF are now CSI
  • sperm is injected into the oocyte

Blastocyst Development- 1994

  • decades of research of metabolic need of pre-implanatation embryos

Sex selection= 1998

  • capacity to sort X or Y bearing chromosome sperm and being able to inseminate based on chromosome
  • production of only male or female embryos
  • only allowed in aus. based on sex linked diseases
  • China-- very high pressure for sex selection= single child policy and a tradition for male children (it is not legal but it does happen)

Dolly= 2000

  • stem cells, cloning and genetic transfer
  • first demonstration of being able to clone an animal
  • therefore you can easily clone a human-- the same technology therefore very controversial
  • gvmt bodies and regulatory bodies preventing the cloning of humans-- banned in most/all countries (laws restrict drs actions--> no dr is going to break the law)
  • problem is-- certain aspects of technology leads to health problems of the embryo

Ovarian reserve testing = 2005

  • the ability to approximate the number of oocytes a woman has left-- blood test to measure AMH and AFC (ultrasound) can be used to estimate the Ovarian reserve
  • important due to the increase in average maternal age
  • womans fertility depletes almost completely at 40 (due to the loss of primordial follicles)
  • can sell eggs in America-- clincaly and comercialy relavant in the last 10 years
  • new form is being developed that tests for a hormone released directly from the oocyte
  • particularly relevant for young women with cancer or a carrier of breast cancer gene (allowing women to preserve ovarian reserve prior to treatments that can deplete/destroy the ovary)

OOcyte Freezing, social freezing =2008

  • ability to delay child bearing years
  • in conjunction with ORT

Whole genome screening of embryos= 2013

  • shanghai
  • examining all the genes in an embryo

Recently= mitochondrial transfer-- three types of genetic material in offspring

  • Built on the back of 20 years of animal research

Bovine industry--> freezing of embryos

  • allowing freezing of embryos in liquid nitrogen


1.Ovarian Hyperstimulation--> to generate multiple follicles and oocytes-- stems from animal research

  • normally only one follicle reaches ovulation
  • ~30 follicles do not make it to ovulation but will also be lost
  • Inject patient with FSH (pituitary) promoting the growth of follicles--> tightly controlled by negative feedback of progesterone
  • Increase FSH (~10 injections and pituitary down regulation stopping the negative feedback) resulting in ~20 follicles rather than 1
  • Oestrogen produced by follicles granulosa cells-- 20 x more oestrogen produced with the ovulation of 20 follicles resulting in Ovarian Hyperstimulation Syndrome
  • Large dose of hCG-- analog to LH-- stimulating maturation of oocyte in the follicle and allowing them to be collected
  • LH normally stimulates ovulation

2. Oocyte Pick-up--> originally by laproscopy (through the abdominal wall); ~20 years to trans-vaginal oocyte recovery (ultrasound probe with needle at end inserted into vagina and through the ovary wall-- out-patient procedure, usually under light sedation)

3. Sperm retrieval--> ~90% via masturbation; some by surgery ( problems with ejaculation or low numbers of sperm-- from epidydimis or testes)

  • capacitation-- cultured for a few hours

4. IVF

  • occurs in a dish
  • ICSI-- sperm injection into the oocyte via two glass needles --> guarantees that the sperm gets into the oocyte (practically curing male infertility over night)
  • very technical procedure- lots of patients and a growing area of ART

5. Embryo culture

  • With 8 cells the embryo can be frozen and transfered into the patient (day 3)
  • Blastocyst growth is more common to be transferred into the patient-- higher likelihood for success

6. Transfer of Embryo

Ovarian in Vitro Maturation-- collection of follicles at a less mature stage (cultured for ~24 hours before going to IVF)

  • follicle arrested at P1
  • mature as normally once in a solution of LH (complex medium, protein, FSH)
  • differences to IVF--- there are no hormones; the oocyte is just picked up and then cultured in vitro

Lab 3

Transition from week 3 trilaminar embryo into early development (weeks 3 & 4)


  • Crown-rump measurement (~3cm) --> not an actual measurement of the embryo due to shrinkage (a result of fixation) and different fixatives and variables result in different degrees of shrinkage.
  • Major events occurring in week 3
  • amniotic sac on the dorsal side of the embryo--> sac lined with ectoderm (embryonic and epithelium lining cavity)
  • surface of amniotic sac --> extra embryonic mesoderm-- contributing to fetal membranes and placenta
  • Corionic cavity lined with extra-embryonic mesoderm
  • endoderm forms the ventral side of the embryo
  • Cranial end--> cardiogenic region; differentiating within mesoderm
  • folding of embryo ventrally bringing connecting stalk to the ventral side of embryo
  • umbilicus --> site of connection of chord, yolk stalk etc
  • sac covering embryo-- therefore the remainder of embryonic and fetal development occurs within the sac
  • oral membrane -- primitive mouth area
  • folding of the yolk sac into the embryo forms the fore, mid and hind gut
  • beneath heart-- transverse septum (mesoderm) contributing to liver development and the central tendon of the diaphragm
  • fold of endoderm extending into the connecting stalk -- blind ended tube (hollow)-- allantois (remnant of evolution or an unidentified specialised function) forming the superior end of the urinary bladder
  • Midgut connected by yolk stalk to the yolk sac (outside the embryo)
  • blood vessels that form on the yolk sac are important to the development of portal vasculature
  • Head paraxial mesoderm segments into somites (44-48 pairs) in a rostro-caudial direction (from head to bottom)
  • Intermediate Mesoderm forms 3 pairs of kidneys (pronephros, mesonephros and metanephros)
  • Lateral plate mesoderm --> horse shoe cavity around the cranial end separting mesoderm into somatic and splanchnic mesoderm (forming heart)
  • horse shoe cavity forms the 3 body cavities (pericardial, pleural and peritoneal)


  • embryo has different stem cells in different locations eg GIT, skin etc
  • if they grow out of control-- form tumors and cancers
  • totipotential eg blastomere--> undifferentiated cells that can form many tissues or cells
  • Primary vesicles (3) form and these then subdivide into the 5 secondary vesicles
  • GIT nervous system--> innervation of peristalsis (regulated by enteric ns)
  • Pharyngeal Arches ( 1-4 +6 --> 1 is largest and 4+6 fuse)
  • arch 5 if it occurs is a transient structure--> present in non-humans
  • each sensory system has its own placode that is associated with it eg otic placode forming the entire inner ear; optic placode forms the lens of the eye
  • limb buds initially formed (upper) on either side of the heart
  • limb buds are ecto and endoderm


  • Neural rube defects
  • defective fusion of the neural folds--> dysraphism
  • folate in flour
  • still a slight occurance of these abnormalities because there are many ways to generate these abnormalities independent of folate eg clef palate

Lab 4

Blood and early development of the Cardio-vascular system

  • fetal cells necessary to make placenta only available at implantation
  • blastocyst--> major player on placental development (trophoblast- forming syncitiotrophoblast and cytotrophoblasts)
  • syn-- outside, multi nucleated, synthesis hCG (secreted locally and taken up by maternal blood at lacunae)
  • cyt-- inside, single nucleus
  • luteum is yellow when producing hormone and albicans is white when not producing hormone
  • luteum produces estrogen and progesterone
  • progesterone suspends uterus lining in the secretory phase and therefore preserving implantation
  • placenta takes over from luteum--> endocrine role
  • extra-villus cytotrophoblast--> surround ends of placental vessels and important in maintaining placental blood flow
  • decidualisation--> important in contributing maternal component of placenta
  • three extra-embryonic chambers -- amniotic, yolk sac and chorionic cavity (largest space outside of embryo, lined with extra-embryonic mesoderm)
  • conceptus-- embryo and extra-embryonic cells--> all cellular products
  • when conceptus is divided (wk2-4)- uterine side vs. maternal blood side
  • uterine side--> not richly vascularised and small amount of villus development
  • Maternal blood side --> access nutrients, strong growth factor drive, large amount of villus development and richly vascularised
  • chorion laeve--> smooth, not many villi
  • chorion frondosum --> leafy chorion; side where placenta will form
  • desudua vasalis-- maternal contribution to placenta
  • capsularis -- lie over chorion laeva
  • parietalis
  • three stages of villi development--primary, secondary and tertiary
  • primary villi--> trophoblastic shell cells
  • secondary villi--> extra-embryonic mesoderm grows into villi
  • tertiary villi--> formation of blood vessels
  • fetal infections passed through the placenta eg malaria -- a number of immune structures to pass through
  • abnormal placentation-- in lobes or cord not centric can lead to impaired embryonic development
  • embryonic contribution to the placenta-- cytotrophoblast layer, trophoblast column (connecting site for villi), anchoring villi (attaching to maternal decidua), syncitiotrophoblast (as islands and on the outside of cytotrophoblasts)
  • cytotrophoblasts-- transient, from cuboidal to squamous and can degenerate
  • no direct contact between maternal and fetal blood
  • during pregnancy-- arterial/venous shunt formed in uterine wall (homogenous oxygen level within lacunae)
  • Eclampsia-- hypertension resulting in the decrease of oxygen exchange
  • accreta--> abnormal adherence and the absence of basalis