How are they used for treating diseases?
What are stem cells?
Stem cells are unspecialized cells from which differentiated cells develop. There are two different types, adult stem cells and embryonic stem cells. Embryonic stem cells are pluripotent, more versatile and , capable of producing every cell type in the body. They come from embryos that are three to five days old. They can also be found in the placenta, amniotic fluid and the umbilical cord blood. Adult stem cells are multipotent and are limited to replaced cells in the tissue in which they are found. They can come from bone marrow and teeth.
This picture shows how stem cells can self 1) self renew and 2) differentiate into a specialized, mature cell.
Stem cells in the umbilical chord
Stem cells in the bone marrow
What are they used for?
Stem cells can be used for treating injuries or diseases. An example is the hematopoietic stem cell, which is a blood - forming stem cell in the bone marrow. HSCs are currently one of the most commonly used stems cell for treating human diseases that involve a damaged or deficient immune system. Also, some stem cells can be used for skin graft on patients with severe burns on large areas of the body. The only disadvantage to this is, the new skin contains no hair follicles or sweat glands.
Why is it considered unethical?
The controversy is within the embryotic stem cell research. The people who believe it to be unethical believe that human life begins at conception. The only way to obtain these stem cells is to destroy the three - five day old embryo (blastocyst) and for some people, that is considered killing a human. Against this, scientist argue that the blastocyst has no human features therefore should not be considered a human being.