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NON ASSESSABLE MATERIAL/DRAFT WORK

--Z3332337 11:52, 25 July 2012 (EST)


ANAT2341 – LAB 2 01/08/12

Fertilisation

• Purposes for research into fertilisation:

- Infertility

- Farming industry

- Contraception

PubMed journal articles: Sperm penetration through the cumulus & Sperm-Egg Interaction.

• The oocyte and spermatozoa alike, undergo reactions for sperm membrance fusion, cortical reaction & the 2nd meiotic division. Calcium flooding can trigger the cortical reaction and Cyclohexamide prevents the polarisation of the 2nd polar body, and therefore these mechanisms alter the natural pathway.

• Imprinting is...

Pregnancy - Week 1

• The uterine tube is a CILIATED EPITHELIUM.

• The zona pellucida (pale ring around te ooccyte) is a specialised extra-cellular matrix made of GLYCOPROTIENS (ZP1, ZP2, ZP3, & ZP4 in humans). These glycoproteins are species specific. Its functions are:

- Protection and flexibility - Protects blastocyst as well while proliferating - Patterns the development of the blastocyst and have a squamous morhphology. - Sperm receptor - Prevents implantation - Prevents polyspermy; modified by the cortical granules.

• ADPLANTATION

• IMPLANTATION: takes ~1 week (specific to week 2).

• The inner cell mass of the blastocyst forms the EMBRYO.

• Epigenetics: “re-programming” of the PATERNAL GENETICS by mechanisms other than the changes in the underlying DNA sequence.

• Telomeres: at the end of the chromosomes are related to aging and are maintained by TELOMERASE. Telomere length

Week 2

• In the 2nd week, TWO layers of trophoblasts develop. - Peripheral: CYTOTROPHOBLASTS - Central: SYNCITIOTROPHOBLASTS

• Later in the movie the amniotic cavity forms adjacent to the epiblast layer(blue) and spaces in the syncitiotrophoblast layer are filled with maternal blood, lacunae.

• In this week , the embryo is referred to as the BILAMINAR EMBRYO.

• In Carnegie Stage 4, implantation starts.

• The endometrium is called the DECIDUA. DECIDUA BASALIS at the time of implantation and “DECIDUALISES” the rest of the of the uterus. - “That part of the decidua that interacts with the trophoblast is the decidua basalis (also called decidua placentalis). The remainder of the decidua is termed the decidua parietalis or decidua vera. Also, there is the decidua capsularis, which grows over the embryo on the luminal side, enclosing it into the endometrium and surrounding the embryo together with decidua basalis.” [1]