A term covering a range of conditions in which there is progressive impairment of the structure and function of part of the body. The definition excludes conditions due to inflammation, infection, altered immune responses, chemical or physical damage, or cancerous change. The number of specialized cells or structures in the organ affected is usually reduced, and cells are replaced by connective tissue or scar tissue. Degenerative nervous system disorders include Alzheimer’s disease, motor neuron disease, Huntington’s disease, and Parkinson’s disease. Degenerative disorders of the eye include Leber’s optic atrophy and senile macular degeneration. Degenerative disorders of the joints include osteoarthritis. Some hardening of the arteries seems to be a feature of aging. In some people, degenerative changes in the muscle coat of arteries are unusually severe and calcium deposits may be seen on X-rays (as in Monckeberg’s sclerosis, a type of arteriosclerosis). Several degenerative disorders, such as the muscular dystrophies, are now known to be genetic.
Degenerative disorders |
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