Ach (Acetylcholine ) - primary neurotransmitter in the muscle response.

Ach-esterase- substance that breaks down Ach into its primary components, acetate and choline, as part of the functioning of the synapse.

Ach receptors (AChR) - receptors that accept Ach to initiate a muscle response.

Ach vesicle - a pocket of membrane in the pre- synaptic terminal that contains Ach to be released into the synaptic cleft.

Antibody - an immunoglobulin molecule with a specific amino acid sequence used for identification.

Anti-fab - along with Fab is the other component of the IgG, is very crucial in the cross linking process.

Antigen - "marker" that begins the immune response when coming in contact with an antibody.

B Cells- a specialized cell that recognizes certain antigens of invading cells. Upon contact with the specific antigen it begins to divide rapidly to form plasma cells.

Class II major histocompatibility complex antigens (MHC Class II) - marker proteins on the surface of all vertebrate cells that communicates to the body that the cell is of the "self" and belongs to the body. Class II cells are specific for macrophages and B-cells as they play an important role in immune system communication.

complement - in a nutshell, compliment is an antigen destroying substance in the blood serum that is composed of about 20 different proteins.

Cross-link - linkage by covalent bonds of two polymers, in this case the IgG or Fab/ Anti-fab particles form bonds with the receptor and block Ach binding. It also speeds up the process of endocytosis.

Cytotoxic T Cells - destroy infected cells and bacteria by lysing ( punching a hole in) the invading cell's membrane.

Endocytosis - similar to phagocytosis where the cell extends its membrane and engulfs extracellular material into vesicles.

epitopes - a binding-site for an antibody on a cell.

Experimental Autoimmune Myasthenia Gravis - also known as EAMG, it is induced in the laboratory by inhibiting or destroying AchR' s in some fashion, most often with bungarotoxin.

Fab fragment - part of the IgG that binds to the antigen.

Helper T Cells - acts as the warning system of the immune system by starting T-cell and B-cell response.

Hyperplasia - increase in the number of cells in an organ, excluding tumors. In the case of myasthenia gravis, the thymus grows abnormally large.

IgG - immunoglobulin G, one of many antibodies present in the blood serum but is most prevalent about 3 weeks after infection.

Inducer T Cells - not directly involved in the immune response, these cells help develop T-cells in the thymus.

Lymphocyte - white blood cells that are divided into T-cells and B-cells.

Lymphokines - a factor secreted by activated T cells that cause other T cells ( those that have come in contact with certain antigens ) to multiply and divide. These new T cells now have the ability to recognize the antigen.

Lysosome - a vesicle of low pH in a cell that breaks down exogenous materials.

Macrophages (or antigen presenting cells)- a white blood cell that serves as an antigen marker for B-cells and later acts as a phagocyte by engulfing the antigen marked cell.

Monocyte - the precursor of the macrophage.

Myoid cells - muscle cells, in this case, in the thymus.

Peptides - short proteins that serve as chemical messengers.

Phagocytes - a white blood cell that destroys infected cells by extending its cell membrane to encompass the other cell in a process known as phagocytosis.

plasma cells - antibody protein producer that marks the particular antigen recognized by the B-cell.

steric hinderance - interference with a feasible chemical reaction. Here it means the physical inhibition or blockage of the Ach binding site by another molecule.

Suppressor T Cells - the inhibitor cell that decreases the activity of T-cells and B-cells after an infection has been put under control.

target antigen - the specific antigen that a certain B-cell attacks, in this case, the mistaken AchR.

T Cells (or T lymphocytes) - generic name for this type of white blood cell. They have specific functions and specific names, the most important of which are talked about later in the text.

T-cell receptor (TCR)- T-cells use the TCR to identify foreign molecules. Anything that binds to the TCR is recognized as an invading molecule.

Theory of Molecular Mimicry - states that T cells may accidentally recognize the body's own cells as foreign because of the similarity it's protein chain shares with a foreign antigen's protein chain. It is speculated that only 5 amino acids have to match in sequence ( out of hundreds ) for the T cells to mistake them. An example is herpes simplex. It seems to share an amino acid sequence with the AchR which, if an autoimmune response occurs, can cause myasthenic symptoms.

Thymomas - abnormal cell growth in the thymus, basically a tumor.

Thymus - important gland located approximately above the heart that coordinates and builds the developing immune system. After puberty, the thymus begins to shrink and becomes mostly fatty tissue.

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