From Embryology

Lab 4 Online Assessment

  1. The allantois, identified in the placental cord, is continuous with what anatomical structure?
  2. Identify the 3 vascular shunts, and their location, in the embryonic circulation.
  3. Identify the Group project sub-section that you will be researching. (Add to project page and your individual assessment page)

Lab Attendance

--z3291622 12:53, 28 July 2011 (EST)

Lab 1 Assessment

--Z3291622 22:45, 2 August 2011 (EST)

1. Identify the origin of In Vitro Fertilization and the 2010 nobel prize winner associated with this technique. The history of IVF can be dated back as early as the 1890’s when the first known case of embryo transplantation in rabbits was reported. In 1959, Chang MC produced undisputable evidence of IVF through his work on rabbits. The breakthrough in IVF was the birth of the first successful ‘test-tube’ baby, Louise Joy Brown, born on the 25th of July 1978 in Oldham, England through the work of Patrick Steptoe and Robert Edwards. The Nobel Prize in Physiology or Medicine 2010
was awarded to Robert G. Edwards for the development of in vitro fertilization.

2. Identify a recent paper on fertilization and describe its key findings. Copy and paste the reference from a search of Pubmed and write a few lines about the paper.

The effectiveness of Assisted Reproductive Technologies (ART) depends on many factors. Implantation failure has been identified as the main cause of failure. Thus the purpose of this paper was to compare the effectiveness of two IVF techniques; IMSI (intracytoplasmic morphologically selected sperm injection) and ICSI (intracytoplasmic sperm injection) in couples that have already experienced repeated implantation failures. The results indicated that while IMSI did not significantly improve the clinical outcome compared to ICSI, it decreased rates of miscarriage (≈50% reduced). However more research into these techniques is needed to draw out much more concrete and reliable evidence.


Reference: Oliveira, J., Cavagna, M., Petersen, C., Mauri, A., Massaro, F., Baruffi, R., & Franco, J Jr. (2011). Pregnancy outcomes in women with repeated implantation failures after intracytoplasmic morphologically selected sperm injection (IMSI). Reproductive Biology and Endocrinology, 9:99. doi:10.1186/1477-7827-9-99

3. Identify 2 congenital anomalies. Just name them.

Hypospadias Trisomy 21 (Down Syndrome)

--Mark Hill 10:00, 3 August 2011 (EST) These are good answers to Lab 1 assessment.

Lab 2 Assessment

1. Identify the ZP protein that spermatozoa binds and how is this changed (altered) after fertilization.

The human Oocyte is surrounded by an extracellular coat of gylcoproteins; Zona Pellucida (ZP). This coat is composed of four glycoproteins; ZP1, ZP2, ZP3 & ZP4. Studies show how during fertilization ZP3 acts as a receptor for the capacitated (matured) spermatozoa. ZP4 also binds to the anterior head of the matured sperm. Both these glycoproteins that bind the spermatozoa induce a process known as acrosomal exocytosis (AE). This AE process involves the exocytosis of the acromosal enzymes that digests the substance of the ZP exposing the underlying ZP2 which bind sperm, facilitating the membrane fusion between egg and sperm. Thus ZP2 acts as a secondary sperm receptor. The fusion of sperm and egg leads to an intracellular influx of calcium which triggers the cortical reaction; release of cortical granules (mixture of enzymes and proteases) that alters the ZP3 of zona pellucida to prevent polyspermic fertilization by cross linking and solidifying the zona pellucida.

Reference: Ganguly, A., Bansal, P., Gupta, T., Gupta, S. (2010). ‘ZP domain’ of human zona pellucida glycoprotein-1 binds to human spermatozoa and induces acrosomal exocytosis. Reproductive Biology and Endocrinology. Ch 8:110.

2. Identify a review and a research article related to your group topic. (Paste on both group discussion page with signature and on your own page)

Research Article:

Greer, P., Hanayama, R., Bloodgood, B., Mardinly, A., Lipton, D., Flavell, S., & Greenber, M. (2010). The Angelman Syndrome Protein Ube3A Regulates Synapse Development by Ubiquitinating Arc. Cell, 140(5), 704-716. doi:10.1016/j.cell.2010.01.026

The aim of this research paper is to find out how the Ube3A gene mutation causes cognitive impairment in individuals with Angelman Syndrome. The research is specifically looking into the role of Arc (synaptic protein) and AMPA (subtype of glutamate receptors). The experimental data suggests a relationship between the disruption of Ube3A activity and decrease in AMPA expression and how this can be utilised in the treatment of AS by using drugs that promote AMPA receptor expression.

Review Article:

Pelc, K., Cheron, G., & Dan, B. (2008). Behaviour and neuropsychiatric manifestations in Angelman Syndrome. Neuropsychiatric Disease and Treatment, 4(3), 577-584.

         Angelman Syndrome is most often characterised by symptoms such as happiness, profuse smiling and poorly specific laughing.  This review article sheds light on other less obvious but more debilitating features of Angelman Syndrome, such as areas of cognition, motor control, epilepsy, sleep etc.

Lab attendance

--Warnakulasooriya Fernando 12:58, 4 August 2011 (EST) nce