Examples of stem cell in the following topics:
-
- Symmetric division maintains stem cell lines and asymmetric division yields differentiated cells.
- Stem cells are undifferentiated biological cells found in multicellular organisms, that can differentiate into specialized cells (asymmetric division) or can divide to produce more stem cells (symmetric division).
- In mammals, there are two broad types of stem cells: embryonic stem cells, which are isolated from the inner cell mass of blastocysts, and adult stem cells, which are found in various tissues.
- Notably, stem cells divide asymmetrically to give rise to two distinct daughter cells: one copy of the original stem cell as well as a second daughter programmed to differentiate into a non-stem cell fate.
- This diagram illustrates stem cell division and differentiation, through the processes of (1) symmetric stem cell division, (2) asymmetric stem cell division, (3) progenitor division, and (4) terminal differentiation.
-
- An oligopotent stem cell is limited to becoming one of a few different cell types.
- Stem cells are unique in that they can also continually divide and regenerate new stem cells instead of further specializing.
- There are different stem cells present at different stages of a human's life, including the embryonic stem cells of the embryo, fetal stem cells of the fetus, and adult stem cells in the adult.
- One type of adult stem cell is the epithelial stem cell, which gives rise to the keratinocytes (cells that produce keratin, the primary protein in nails and hair) in the multiple layers of epithelial cells in the epidermis of skin.
- Adult bone marrow has three distinct types of stem cells: hematopoietic stem cells, which give rise to red blood cells, white blood cells, and platelets ; endothelial stem cells, which give rise to the endothelial cell types that line blood and lymph vessels; and mesenchymal stem cells, which give rise to the different types of muscle cells.
-
- New blood vessels are formed from endothelial stem cells, which give rise to the endothelial cells which line the vessels.
- Endothelial stem cells (ESCs) are one of three types of stem cells found in bone marrow.
- ESCs have the characteristic properties of a stem cell: self-renewal and differentiation.
- These parent stem cells, ESCs, give rise to endothelial progenitor cells (EPCs), which are intermediate stem cells that lose potency.
- Progenitor stem cells are committed to differentiating along a particular cell developmental pathway.
-
- Three basic categories of cells make up the mammalian body: germ cells, somatic cells, and stem cells.
- Examples of stem and progenitor cells include:
- Hematopoietic stem cells (adult stem cells) from the bone marrow that give rise to red blood cells, white blood cells, and platelets
- Mesenchymal stem cells (adult stem cells) from the bone marrow that give rise to stromal cells, fat cells, and types of bone cells;
- Epithelial stem cells (progenitor cells) that give rise to the various types of skin cells
-
- Hematopoietic stem cells reside in the bone marrow and have the unique ability to differentiate into all of the mature blood cell types.
- The process of the development of different blood cells from hematopoietic stem cells to mature cells is called "hematopoeisis. "
- As a stem cell matures, it undergoes changes in gene expression that limit the cell types that it can become and moves it closer to a specific cell type.
- For the stem cells and other undifferentiated blood cells in the bone marrow, blood cells are determined to specific cell types by random.
- A comprehensive diagram showing the development of different blood cells from hematopoietic stem cell to mature cells.
-
- Plant meristems are centers of mitotic cell division, and are composed of a group of undifferentiated self-renewing stem cells from which most plant structures arise.
- In that sense, the meristematic cells are frequently compared to the stem cells in animals, which have an analogous behavior and function.
- Meristematic tissues are cells or group of cells that have the ability to divide.
- Meristematic tissues are found in many locations, including near the tips of roots and stems (apical meristems), in the buds and nodes of stems, in the cambium between the xylem and phloem in dicotyledonous trees and shrubs, under the epidermis of dicotyledonous trees and shrubs (cork cambium), and in the pericycle of roots, producing branch roots.
- Cells of this zone have a stem cell function and are essential for meristem maintenance.
-
- B cells and T cells are the major types of lymphocytes.
- Mammalian stem cells differentiate into several kinds of blood cell within the bone marrow.
- B cells mature into B lymphocytes in the bone marrow, while T cells migrate to, and mature in, a distinct organ called the thymus.
- Effector lymphocytes function to eliminate the antigen, either by releasing antibodies (in the case of B cells), cytotoxic granules (cytotoxic T cells) or by signaling to other cells of the immune system (helper T cells).
- Mammalian stem cells differentiate into several kinds of blood cell within the bone marrow.
-
- T cells originate from haematopoietic stem cells in the bone marrow and undergo positive and negative selection in the thymus to mature.
- They can be distinguished from other lymphocytes, such as B cells and natural killer cells (NK cells), by the presence of a T cell receptor (TCR) on the cell surface.
- All T cells originate from haematopoietic stem cells in the bone marrow, which are capable of differentiating into any type of white blood cell.
- A T cell is then signaled by the thymus to become a CD4+ cell by reducing expression of its CD8 cell surface receptors.
- The remaining cells exit the thymus as mature naive T cells.
-
- The stem and other plant organs are primarily made from three simple cell types: parenchyma, collenchyma, and sclerenchyma cells.
- The dermal tissue of the stem consists primarily of epidermis: a single layer of cells covering and protecting the underlying tissue.
- When the stem is viewed in cross section, the vascular bundles of dicot stems are arranged in a ring.
- Ground tissue is mostly made up of parenchyma cells, but may also contain collenchyma and sclerenchyma cells that help support the stem.
- The central pith and outer cortex of the (a) flax stem are made up of parenchyma cells.
-
- Growth in plants occurs as the stems and roots lengthen.
- It is the result of cell division in the shoot apical meristem .
- It is caused by cell division in the lateral meristem .
- Most primary growth occurs at the apices, or tips, of stems and roots.
- The thickening of the stem that occurs in secondary growth is due to the formation of secondary phloem and secondary xylem by the vascular cambium, plus the action of cork cambium, which forms the tough outermost layer of the stem.