what is the protein that the sperm binds to on the surface
name the three stages of follicle development in the ovary
it begins of with the primordial follicle, and then becomes the preantral follicle followed by the graffian (antral) follicle.
--Sando Rashed 13:11, 6 August 2009 (EST)
1. What factor do the synctiotrophoblast cells secrete to support the ongoing pregnancy? they secrete proteolytic enzymes. they help the blastocyst into the endometrial wall, they also secrete hCG. 2. What does the corpus luteum secrete to prevent continuation of the menstrual cycle? progesterone as well as estrogen 3. What are the 2 main tissues to be derived from the germ cell layer continuous with the lining of the amniotic sac? the peripheral of the ectoderm forms the epidermis and the CNS and the skin of the body
--Sando Rashed 14:05, 13 August 2009 (EST)
1. What period of human development (in weeks) do the 23 Carnegie stages cover? 8 weeks and 4 days 2. What process leads to the conversion of the bilaminar embryo into the trilaminar embryo? Gastrulation 3. What part of the somite will contribute to the vertebral column? The sclerotome 4. What carniege stage does the human neural tube normally completely close? Stage 13 (week4), the neural tube normally completely closes.
--Sando Rashed 13:06, 20 August 2009 (EST)
before it enters the embryonic heart it enters the sinus venosus (before this it goes through the common cardial vein)
the dorsal aorta becomes known as the decending aorta
the layers within the tertiary villi are trophectoderm cells, extra embryonic mesoderm and cell that line the blood capillaries (endothelial cells)