Z3218657

1. What is the protein that the sperm binds to on the surface of the ova?

ZP3 protein

2. Name the 3 stages of follicle development in the ovary? Primary Secondary Graafian

Though I thought i loaded this up when I was in Class... At least i thought i did sorry and i also heard the question differently.

--Sally Clarke 13:12, 6 August 2009 (EST)

1.What factor do the synctiotrophoblast cells secrete to support the ongoing pregnancy? HCG (human chorionic Gonadotropin) hormone secreted to stop the menstral cycle by acting on cells in the ovary. These cells in the ovary secrete hormones such as progesterone and oestrogen to stop the menstral flow. It also maintains the Decidua and the Corpus Luteum and secretes proteletic enzymes. HCG in the urine is what a pregnacy test, tests for to determine pregancy.

2.What does the corpus luteum secrete to prevent continuation of the menstrual cycle? The Leteul cells – granulosa and theca (synthesise in the hormone) secretes Progesterone which stops menstral cycle. The corpus luteum is signalled by the HCG produced by the Synctiotrophoblasts.

--Sally Clarke 13:05, 13 August 2009 (EST)

3.What are the 2 main tissues to be derived from the germ cell layer continuous with the lining of the amniotic sac? The main tissues are the Nervous Tissue and Epithelial Layer

Process: Epiblast and hypoblast layers are in the Bilaminal Layers --> formation of the Trilaminal Layers with the ectoderm, mesoderm and endoderm layers. Here the Hyperblast layer is lost and the Yoke, Chorionic and Amnoitic Sac are formed. Yoke sac – layer is lined with endoderm, contributes to the gut formation – The yoke sac is lined with the same cells that will form the gut Corionic sac – aminon fuses with the cornion