Question

29. A sacrococcygeal teratoma is a tumor that arises from remnants of what?

30.  The amniotic cavity appears on the eighth day as a slit-like space between the trophoblast and the what?

31. Where does fertilization usually occur?

32. What is the acrosome reaction

Answer 1

29. Sacrococcygeal teratomas are thought to arise from an area under the coccyx called “Henson’s Node”. This is an area where primitive cells persist (germ cells) that can give rise to cells of the three major tissue layers of an embryo: ectoderm, endoderm, and mesoderm. These embryonic layers eventually give rise to the various cells and structures of the body. Sacrococcygeal teratomas can contain mature tissue that looks like any tissue in the body, or immature tissue resembling embryonic tissues.

30. The amniotic cavity appears on the eighth day as a slitlike space between the trophoblast and the embryoblast.

31.Fertilization usually takes place in a fallopian tube that links an ovary to the uterus. If the fertilized egg successfully travels down the fallopian tube and implants in the uterus, an embryo starts growing.

32.The acrosome reaction is a crucial step during gamete interaction in all species, including man. It allows spermatozoa to penetrate the zona pellucida and fuse with the oocyte membrane.

The function of the acrosome reaction is to help the sperm get through the egg's protective coat and to allow the plasma membranes of the sperm and egg to fuse.

Spermatozoa which are unable to undergo the acrosome reaction will not fertilize intact oocytes.