granulosa cells

(noun)

These cells produce hormones and growth factors that interact with the oocyte during its development.

Related Terms

  • ischemic phas
  • ischemic phase
  • follicular phase
  • luteal phase
  • menstrual cycle

Examples of granulosa cells in the following topics:

  • Hormonal Regulation of the Female Reproductive Cycle

    • 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.
  • Puberty

    • 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.
  • Ovarian Cycle

    • FSH induces the proliferation of granulosa cells in the developing follicles and the expression of luteinizing hormone (LH) receptors on these granulosa cells.
  • Aging and the Endocrine System

    • This decrease in responsiveness can be attributed to a decrease in IGF-I signaling pathways with advanced cell age.
    • Testosterone is a steroid hormone secreted by the Leydig cells.
    • Estradiol is the female equivalent of testosterone and is secreted from granulosa cells.
    • In vitro, cells treated with testosterone demonstrated a decrease in Ab release.
    • Estrogen acts on the nucleus of the cell by binding with the nuclear endoplasmic reticulum (ER).
  • Specific T-Cell Roles

    • 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.
  • Natural Killer Cells

    • 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.
  • Lymphoid Cells

    • The three major types of lymphocyte are T cells, B cells, and natural killer cells.
    • If cancer cells evade NK cell detection for long enough, however, they can grow into tumors that are more resistant to NK cell activity.
    • T cells are involved in cell-mediated immunity whereas B cells are primarily responsible for humoral immunity.
    • There are two types of T cells involved in adaptive, cell-mediated immunity.
    • Following activation, B cells and T cells leave a lasting legacy of the antigens they have encountered in the form of memory cells.
  • Maturation of T Cells

    • T cells belong to a group of white blood cells known as lymphocytes and play a central role in the cell-mediated branch of the adaptive immune system.
    • They are 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.
    • T cells can be either helper T cells or cytoxic T cells based on whether they express CD4 (helper) or CD8 (cytotoxic) glycoprotein.
    • 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.
  • Maturation of B Cells

    • B cells are lymphocytes that play a large role in the humoral immune response (as opposed to the cell-mediated immune response, which is governed by T cells) .
    • Once a B cell encounters its cognate antigen and receives an additional signal from a T helper cell, it can further differentiate into either plasma B cells or memory B cells.
    • B cells exist as clones.
    • A single B cell or a clone of cells with shared specificity, upon encountering its specific antigen, divides to produce many B cells.
    • B cells that encounter antigen for the first time are known as naive B cells.
  • Lymphocytes

    • Subtype 2 helper T cells present antigens to B cells.
    • Suppressor T cells (T-reg cells) retain some of their ability to bind to self-cells.
    • Then mature helper T cells bind their antigen to naive B cells through BCRs.
    • Plasma cell and long-lived B cells that are the main source of antibodies.
    • Memory B cells are dormant B cells with the same BCR as the B cell from which they differentiated.
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