chromaffin cells

(noun)

Neuroendocrine cells are found in the medulla of the adrenal gland (suprarenal gland, located above the kidneys) and in other ganglia of the sympathetic nervous system.

Related Terms

Examples of chromaffin cells in the following topics:

  • Adrenal Medulla

    • Chromaffin cells are the neuroendocrine cells found in the medulla; they are modified post-synaptic sympathetic neurons that receive sympathetic input.
    • When stimulated, chromaffin cells secrete adrenaline and noradrenaline along with enkephalin and enkephalin-containing peptides into the bloodstream.

  • Postganglionic Neurons

    • The two exceptions mentioned above are the postganglionic neurons of sweat glands and the chromaffin cells of the adrenal medulla.
    • The chromaffin cells of the adrenal medulla are analogous to post-ganglionic neurons—the adrenal medulla develops in tandem with the sympathetic nervous system and acts as a modified sympathetic ganglion.
    • Within this endocrine gland, the pre-ganglionic neurons create synapses with chromaffin cells and stimulate the chromaffin cells to release norepinephrine and epinephrine directly into the blood.
    • The postsynaptic cell then goes on to innervate the targeted end effector (i.e., gland, smooth muscle, etc.).
    • The pelvic splanchnic efferent preganglionic nerve cell bodies reside in the lateral gray horn of the spinal cord at the S2–S4 spinal levels.

  • Development of the Urinary System

    • The adrenal medulla forms from neural crest cells that migrate into the fetal cortex and differentiate into chromaffin cells.

  • Preganglionic Neurons

    • The preganglionic, or first neuron will begin at the outflow and will cross a synapse at the postganglionic, or second neuron's cell body.
    • The sympathetic division (thoracolumbar outflow) consists of cell bodies in the lateral horn of the spinal cord (intermediolateral cell columns) from T1 to L2.
    • These cell bodies are GVE (general visceral efferent) neurons and are the preganglionic neurons.
    • The chromaffin cells of the adrenal medulla.
    • This is the one exception to the two-neuron pathway rule: they create a synapse directly onto the target cell bodies.

  • Epinephrine and Norepinephrine

    • Together, these effects lead to increased blood glucose and fatty acids, providing substrates for energy production within cells throughout the body.
    • Norepinephrine is synthesized from dopamine by dopamine β-hydroxylase in the secretory granules of the medullary chromaffin cells and is released from the adrenal medulla into the blood as a hormone.

  • Cellular Differentiation

    • 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

  • Gene Expression in Stem Cells

    • 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.

  • Dendritic Cells

    • 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.

  • Cell Theory

    • 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.

  • 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.