n. the undifferentiated tissue of the early embryo that forms almost entirely from *mesoderm. It is loosely organized and the individual cells migrate to different parts of the body where they form most of the skeletal and connective tissue, the blood and blood system, and the visceral (smooth) muscles.
These are cells in a tissue or tissues in an organ that are concerned with function. These are the characteristic cells or tissues that do the actual stuff. The importance to us is that parenchymal tissues expend much vital energy in their functions and are less tolerant of a degraded environment than the structural mesenchyme. A congested and impaired organ like the liver of a heavy drinker has so much regular dysfunction that eventually the more tolerant and metabolically less particular mesenchymal cells become more common, and the distressed, overworked, and metabolically compromised parenchymal cells become a minority. The structural cells can multiply with ease in a poor environment, the more delicate functional cells cannot-and you end up with the type of cirrhosis sometimes termed mesenchymal invasion disease. The point of this is that the sooner you return an organ or tissue back to the healed state, the more likely you are to have a healthy balance between the structural and functional.... parenchymal
n. the middle *germ layer of the early embryo. It gives rise to cartilage, muscle, bone, blood, kidneys, gonads and their ducts, and connective tissue. It separates into two layers – an outer somatic and an inner splanchnic mesoderm, separated by a cavity (coelom) that becomes the body cavity. The dorsal somatic mesoderm becomes segmented into a number of *somites. See also mesenchyme. —mesodermal adj.... mesoderm
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