Stem Cells

Embryonic stem cells come from the embryo. When the embryo begins to grow the cell starts to specialize. These cells can be transformed into specialized cells to be used in the body.

Induced Pluripotent stem cells (iPS) have lots of potential since they can specialize like the embryonic cells. Since these cells come directly from the patient the chance that the cells will be rejected is not present. The downfall is that these cells have a potential to create tumors.

Adult stem cells/Somatic stem cells primary role is to repair and maintain the tissue in a living organism. These cells can be found in many organs and tissues in the adult body such as; brain, bone marrow, blood vessels, skeletal muscle, teeth, skin, heart and many more. These cells only divide when there is a need for more cells to maintain tissues, disease, or tissue injury. The problem with these is that their capability of division is limited, therefore large quantities of adult stem cells are difficult.

Specialization is when the scientists trick the stem cells to turn into what they want. The scientists grow them in petri dishes to create many colonies. Then with the use of growth factors the scientists differentiate the cells into specific tissues that their trying to make.

Transplants are always needed yet there is never enough to go around. So it would be great if we could use stem cells to help the organs in need. Stem cells have the posibility to treat/cure diseases like leukemia, cancer, can make skin grafts, healing of tendon and ligament damage in horses legs, diabetes, strokes, alzheimers, parkinson's, muscle repairs, and possibly even spinal cord injuries.

First a sperm has to fuze with an egg, in order to become fertilized. Sometimes the sperm has a difficult time getting through the egg's shell so the sperm goes through acrosome reaction. In this process a reaction occurs in acrosome (cap-like structure) of the sperm as it begins to approach the egg. The surrounding membrane of the acrosome fuses with the plasma membrane of the sperm which exposes what is inside the acrosome; such as enzymes that break down the shell and allow fertilization.

A cortical reaction is when a sperm cell unites with an egg's plasma membrane. This ensures that no other sperm can fertilize this particular egg.

Cleavage begins in a zygote cell. The zygote cell goes under a series of rapid mitotic divisions. There is no growth however there is DNA synthesis. Cleavage is complete with the formation of a blastula (a hallow ball of cells with a liquid cavity).

Gastrulation is when the blastula gets transformed into a gastrula containing 3 layers of cells. The ectoderm is the outermost layer, forming skin, hair, nerves, and sweat glands. The mesoderm is the middle layer which helps form things associated with movement and support, such as muscles, organs, bone and cartilage. The endoderm is the innermost layer which helps create inner lining, tissues, organs of the digestive system. The archenteron is a new cavity located inside the endoderm.

Organogenesis occurs right after gastrulation, it is a process by which the 3 layers develop into organs.