My·o·sin n.  Physiol. Chem. A protein present in muscle, serving as the principle contractile protein in muscle contraction.
 Note: It was earlier considered as being formed in the process of coagulation which takes place in rigor mortis.  See Muscle plasma, under Plasma.
 Note: ☞ Myosin belongs to the group of globulins.  It is insoluble in water, but soluble in dilute solution of salt, and is especially characterized by being completely precipitated by saturation of its solutions with salt.

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 Plas·ma n.
 1. Min. A variety of quartz, of a color between grass green and leek green, which is found associated with common chalcedony. It was much esteemed by the ancients for making engraved ornaments.
 2. Biol. The viscous material of an animal or vegetable cell, out of which the various tissues are formed by a process of differentiation; protoplasm.
 3. Unorganized material; elementary matter.
 4. Med. A mixture of starch and glycerin, used as a substitute for ointments.
 Blood plasma Physiol., the colorless fluid of the blood, in which the red and white blood corpuscles are suspended.  It may be obtained by centrifuation of blood to remove the blood cells.  It is distinguished from serum in that plasma still has the fibrin of blood, and may be clotted, while in serum the fibrin has been removed.
 Muscle plasma Physiol., the fundamental part of muscle fibers, a thick, viscid, albuminous fluid contained within the sarcolemma, which on the death of the muscle coagulates to a semisolid mass.

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 Se·rum n.  Physiol. (a) The watery portion of certain animal fluids, as blood, milk, etc. (b) A thin watery fluid, containing more or less albumin, secreted by the serous membranes of the body, such as the pericardium and peritoneum.
 Blood serum, the pale yellowish fluid which exudes from the clot formed in the coagulation of the blood; the liquid portion of the blood, after removal of the blood corpuscles and the fibrin.
 Muscle serum, the thin watery fluid which separates from the muscles after coagulation of the muscle plasma; the watery portion of the plasma. See Muscle plasma, under Plasma.
 Serum albumin Physiol. Chem., an albuminous body, closely related to egg albumin, present in nearly all serous fluids; esp., the albumin of blood serum.
 Serum globulin Physiol. Chem., paraglobulin.
 Serum of milk Physiol. Chem., the whey, or fluid portion of milk, remaining after removal of the casein and fat.

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