What is a stem cell?
Stem cells have the ability to divide for indefinite periods in culture and to give rise to specialized cells. They are best described in the context of normal human development. Human development begins when a sperm fertilizes an egg and creates a single cell that has the potential to form an entire organism. This fertilized egg is totipotent, meaning that its potential is total. In the first hours after fertilization, this cell divides into identical totipotent cells. This means that either one of these cells, if placed into a woman's uterus, has the potential to develop into a fetus. In fact, identical twins develop when two totipotent cells separate and develop into two individual, genetically identical human beings. About four days after fertilization and after several cycles of cell division, these totipotent cells begin to specialize, forming a hollow sphere of cells, called a blastocyst. The blastocyst has an outer layer of cells and inside the hollow sphere, there is a cluster of cells called the inner cell mass.
The outer layer of cells will go on to form the placenta and other supporting tissues needed for fetal development in the uterus. The inner cell mass cells will go on to form virtually all of the tissues of the human body. Although the inner cell mass cells can form virtually every type of cell found in the human body, they cannot form an organism because they are unable to give rise to the placenta and supporting tissues necessary for development in the human uterus. These inner cell mass cells are pluripotent — they can give rise to many types of cells but not all types of cells necessary for fetal development. Because their potential is not total, they are not totipotent and they are not embryos. In fact, if an inner cell mass cell were placed into a woman's uterus, it would not develop into a fetus.
The pluripotent stem cells undergo further specialization into stem cells that are committed to give rise to cells that have a particular function. Examples of this include blood stem cells which give rise to red blood cells, white blood cells and platelets; and skin stem cells that give rise to the various types of skin cells. These more specialized stem cells are called multipotent.
While stem c...
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2. Dr. Gearhart
D. The potential uses of pluripotent stem cells.
1. Better understand human development
2. Testing of experimental drugs
3. Cell Therapies
4. Problems
a.) understanding the basics………
b.) immune system
c.) rejection
E. Adult stem cells.
1.) Myth vs. Fact
F. Some adult stem cells have the same potential as pluripotent stem cells.
1.) Committed, or not?
G. What is wrong with using adult stem cells.
1.) pluripotent stems cells do not exist in adult humans
2.) There are no stem cells for all tissue types in adult humans
3.) An abundance of totipotent cells do not exist in adult humans
4.) IT TAKES TIME TO GROW!
H. Conclusion.
The embryos are usually extras that have been created in IVF (in vitro fertilization) clinics where several eggs are fertilized in a test tube, but only one is implanted into a woman (Crosta, Paragraph 3). The blastocyst consists of an inner cell mass (embryoblast) and an outer cell mass (trophoblast). The outer cell mass becomes part of the placenta, and the inner cell mass is the group of cells that will differentiate to become all the structures of an adult organism(Crosta, Paragraph 4). In a healthy pregnancy, the blastocyst stage continues until implantation of the embryo in the uterus, at which point the embryo is referred to as a fetus. This usually occurs by the end of the 10th week of gestation after all the primary organs of the body have been created (Crosta, Paragraph 5). Human embryonic stem cells are the cells from which all 200+ kinds of tissue in the human body originate. When stem cells are obtained from living human embryos, the harvesting of such cells necessitates the destruction of the
Stems cells are immature cells found in embryos that can develop into any kind of specialized cells. They can form virtually any cell of the human body. These types of stem cells are known as pluripotent cells. Multipotent cells are stem cells that are more mature; they can be found in adults and children. Multipotent cells are not as flexible as pluripotent cells, as they have already developed into more specialized human cells.
Stem cells are mother cells that have potential to develop into a new different cell in the body. It can self-renew or multiply while developing into other types of cells, for example they can become cells of the blood, heart, bones, skin, muscles and brain. Stem cells were discovered in human cord blood in 1978, and in 1998, Thompson, from the University of Wisconsin, isolated cells from the inner cell mass of early embryos (early stage of an animal or person before it is born) and developed t...
Stem cell research is on the forefront of regenerative medicine and biological science. It is the study of certain cells in the inner mass of the embryo that are produced a few days after the embryo forms during the blastocyst stage. They are the most primitive of all human cells. They are undifferentiated cells, which mean the cells are not designated to be any special type of cell, such as a nerve, muscle, or skin cell. The cell's specialization is later influenced by the molecules, which are usually proteins that surround the cell (Marshak 220-223). The proteins are typically produced by the mother, but under certain laboratory conditions, distinctive proteins can be introduced and a definite, mature cell type is produced. The cells that are produced could be implanted into a subject to replace worn out cells, or cells that have been destroyed due to disease or injury.
As the research teams of the EuroStemCell project teach in their educational short film A Stem Cell Story, there are certain stages of development while in the uterus where most of our cells stop dividing and stabilize into a specific kind of cell. They do not mutate throughout our life. These cells are referred to as specialized cells. Once they are damaged or die they cannot regenerate themselves.
To get an idea exactly what embryonic cells are, it is necessary to understand fully how they’re retrieved and composed of. Embryonic stem cells come from eggs that have been fertilized by in vitro, which is an artificial environment outside the living organism such as a test tube. When fertilization is successful, the sperm head carrying the nucleus enters the egg. The egg dives first into two cells, then into four. With more divisions, a multicellular ball of cells known as a blastocyst is formed. Inside the blastocyst is a hollow ball which includes the embryonic stem cells which can be retrieved with a pipette, a small glass tube used to transport a measured volume of liquid, and transferred to a dish. Under certain conditions, the embryonic...
Stem cells are located deep down in our bone marrow. They have the incredible ability of “generating an endless supply of red cells, white cells, and platelets”(1). They have been called the “Mother of all blood cells” due to their ability to regenerate the entire blood supply of a persons body. Just to think that this is possible is actually pretty incredible. The man who claims to be responsible for the discovery of this gem is a immunologist from Stanford University named Irving Weissman, and his collaborators at SyStemix, (a biotech company that he cofounded in 1988, located in Palo Alto, CA). He and his company are so confident about these cells, not only have they obtained a government patent on the process by which these specific cells are separated from other cells, they have also patented the cells themselves. They have even convinced Sandoz Ltd. (a giant Swiss drug-and-chemical company) to purchase 60 percent of the stock for SyStemix for a reported 392 million dollars.
The issue of stem cell research first began on the scientific scene in November of 1998 when researchers first reported the isolation of human embryonic stem cells. The discovery, made by Dr. James A. Thomson, a biologist at the University of Wisconsin, Madison, offered great promise for new ways of treating diseases through stem cell use. The stem cells, which are derived from several-day-old embryos, can theoretically differentiate into virtually any type of human cell, ranging from blood cells to skin cells (American Association for the Advancement of Science, 2011). According to the American Medical Association (2013), a stem cell is an immature cell that has the potential to become specialized into different types of cells throughout the body. There are two basic types of stem cells: adult stems cells and embryonic stem cells. Embryonic stem cells are produced when a newly fertilized egg begins...
There are primarily two different types of stem cells that scientist work with, embryonic stem cells and adult stem cells. Embryonic and adult stem cells each have many advantages and disadvantages regarding their potential use. Adult and embryonic stem cells differ in the number and type of cells that they can become. (Antkowiak, 2001).
Embryonic stem cells (ESC) are cells that have the ability to grow indefinitely, maintain pluripotency and differentiate into all three germ layers. In 1981, two groups first derived them from the inner cell mass of mouse blastocyst and showed that ESCs arise from totipotent cells of the mammalian embryo, have normal karyotypes and are able to have unlimited and undifferentiated proliferation in vivo (Evans and Kaufman, 1981; Martin 1981). A decade later, Thomson et al. derived the first human embryonic stem cell lines (hESC) from cultured human b...
A stem cell is a cell that does not have a specific job, function or structure and are known as undifferentiated cells which have the potential of becoming many different cell types within the human body. Embryonic stem cells are taken from embryos and are known as pluripotent because they can become all cell types of the body. After development, adult stem cells are found to multiply by cell division to replace dying cells and restore damaged tissues. They are known to be limited to differentiating into different cell types of their own original tissue origin. Embryonic stem cells are taken from three main sources in a human including from cell lines that already exist, spare embryos left over from fertility treatment and from custom made embryos. Adult stem cells can be found in organs and tissues like brain tissue, bone marrow, blood vessels, gut, liver and more. Scientists are now trying to discover how some tissues and organs contain a small number of adult stem cells and how these stem cells help to maintain the tissues and organs.
Throughout the past few decades, scientific discoveries in the medical world have advanced tremendously. One rapidly growing field is the use of human stem cells, which possess the capacity to divide and give rise to identical stem cells, and even to form new specific types of somatic tissue cells. The categorical term “stem cell” can be divided even further into two specific types: embryonic stem cells and adult stem cells. Embryonic stem cells are cells which can only be derived from preimplantation embryos, and have proven the ability to form cells of all tissue types; they are pluripotent. Alternatively, there are adult stem cells, which are undifferentiated and begin growing in the earliest stages of life and remain in the body forever.
Embryonic stem cells offer hope for new therapy. They are the cells from which more than 200 different kinds of tissues in the human body originate. Stem cells are the building blocks of all specialized cells; they are the raw material. Under the right conditions, they divide to form daughter cells. From there they become new stem cells or differentiate into specialized cells with a specific function, such as blood cells, brain cells, or bone. Stem cells could also differentiate into specific targeted cells to replace diseased cells with new, healthy ones. In the process of the development of humans, a zygote is a stem cell. A zygote is called a totipotent stem cell because it has the potential to form an entire
Stem cells research can help the human with cancer, birth defects and help to build normal cells it is only normal that we should research stem cells. Stem cells are special cells that are undifferentiated and have the capability to become many other types of cells. All stem cells have the ability to renew, replicate, and divide; thus, producing new cells. These cells are separated into categories according to their potential to become other types of cells. Two main stem cell types are embryonic stem cells and adult stem cells. Embryonic stem cells come from four to five day old embryos. They can be found on the inside of the placenta. These stem cells are considered pluripotent, meaning that they can become almost all possible types of
One of the most popular clinical studies being researched these days is stem cell transplantation. Until recently, moral issues of states and countries haven't allowed research to expound deeply into the unknowns. Within the last ten years though, scientists have made leaps and bounds in finding out concrete facts that this stem cell research has supplied. Tommy G. Thompson, Secretary of Health Services states, "I believe it will open up a world of opportunity for scientists, not only at the NIH, but elsewhere, because it demonstrates a cooperative atmosphere among academia, the private sector, and government that will allow us to move ahead" ("sign stem"1). New ways of conducting stem cell research have made the healing and repairing treatment for many diverse applications.