Examples of theca cells in the following topics:
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- Follicle-stimulating hormone induces the proliferation of granulosa cells in the developing follicles and the expression of luteinizing hormone (LH) receptors on these cells.
- Under the influence of FSH, granulosa cells begin estrogen secretion.
- LH induces androgen synthesis by theca cells, stimulates proliferation and differentiation, and increases LH receptor expression on granulosa cells.
- This also causes endometrial cells to produce receptors for progesterone, which helps prime the endometrium to the late proliferative phase and the luteal phase.
- The surge also initiates luteinization of theca and granulosa cells.
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- LH stimulates the Leydig cells of the testes to make testosterone and blood levels begin to rise.
- For females, as the amplitude of LH pulses increases, the theca cells of the ovaries begin to produce testosterone and smaller amounts of progesterone.
- Much of the testosterone moves into nearby cells called granulosa cells.
- Smaller increases of FSH induce an increase in the aromatase activity of these granulosa cells, which converts most of the testosterone to estradiol for secretion into the circulation.
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- Three basic categories of cells make up the mammalian body: germ cells, somatic cells, and stem cells.
- Pluripotent stem cells undergo further specialization into multipotent progenitor cells that then give rise to functional cells.
- 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
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- 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.
- Stem cells can now be artificially grown and differentiated into specialized cell types with characteristics consistent with muscle or nerve cells through cell culture.
- In one, the daughter cells are initially equivalent but a difference is induced by signaling between the cells, from surrounding cells, or from the precursor cell.
- Stem cells are indicated by (A), progenitor cells by (B), and differentiated cells by (C).
- Pluripotent, embryonic stem cells originate as inner cell mass (ICM) cells within a blastocyst.
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- Dendritic cells are immune cells that function to process antigens and present them to T cells.
- Immature dendritic cells (e.g.
- Mature dendritic cells reside in the T cell zones of the lymph nodes, and in this location they display antigens to T cells.
- Dendritic cells are constantly in communication with other cells in the body.
- This communication can take the form of direct cell-to-cell contact based on the interaction of cell-surface proteins.
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- Cell theory states: living things are composed of one or more cells; the cell is the basic unit of life; cells arise from existing cells.
- The unified cell theory states that: all living things are composed of one or more cells; the cell is the basic unit of life; and new cells arise from existing cells.
- "All cells only arise from pre-existing cells.
- Cells carry genetic material passed to daughter cells during cellular division
- The cell is the basic unit of life and the study of the cell led to the development of the cell theory.
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- T helper cells assist the maturation of B cells and memory B cells while activating cytotoxic T cells and macrophages.
- Differentiation into helper T cell subtypes occurs during clonal selection following T cell activation of naive T cells.
- Cytotoxic T cells (TC cells, or CTLs) destroy virus-infected cells and tumor cells, and cause much of the damage in in transplant rejection and autoimmune diseases.
- Memory T cells comprise two subtypes: central memory T cells (TCM cells) and effector memory T cells (TEM cells), which have different properties and release different cytokines.
- Regulatory T cells (Treg cells), also known as suppressor T cells, are crucial for the maintenance of immunological tolerance.
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- In other words, that original single cell is the ancestor of every other cell in the body.
- Single-celled organisms use cell division as their method of reproduction.
- While there are a few cells in the body that do not undergo cell division, most somatic cells divide regularly.
- A somatic cell is a general term for a body cell: all human cells, except for the cells that produce eggs and sperm (which are referred to as germ cells), are somatic cells.
- The cell cycle is an ordered series of events involving cell growth and cell division that produces two new daughter cells.
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- T cells play a central role in cell-mediated immune response through the use of the surface T cell receptor to recognize peptide antigens.
- T cells do not produce antibody molecules.
- Effector cells include helper T cells, and cytolytic or cytotoxic T cells.
- Another class of T cells called regulatory T cells function to inhibit immune response and resolve inflammation.
- T cells promote the killing of cells that have ingested microorganisms and present foreign antigens on their surface.
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- The role of NK cells is similar to that of cytotoxic T cells in the adaptive immune response.
- NK cells provide rapid responses to virus-infected cells and respond to tumor formation by destroying abnormal and infected cells.
- NK cells use wo cytolytic granule-mediated apoptosis to destroy abnormal and infected cells.
- Virus-infected cells destroyed by cell lysis release their replicated virus particles into the body, which infects other cells.
- Cells that are osponized with antibodies are easier for NK cells to detect and destroy.