Trachea synthetic windpipes; however, a successful method for this method of transplant does not currently exist and development of such a method remains theoretically daunting. The word "trachea" is used to define a very different organ in invertebrates than in vertebrates. Insects have an open respiratory system made up of spiracles, tracheae, and tracheoles to transport metabolic gases to and from tissues. An adult's trachea has an inner diameter of about and a length of about 10 to 11 centimetres (4 in.). It begins at the bottom of the larynx, and ends at the carina, the point where the trachea branches
Traditional Chinese medicines derived from the human body were successfully making quasi-empirical preparations of active substances with androgens and estrogens, a technique that modern biochemists did not develop until the early 20th century. The physician William C. Cooper and the sinologist Nathan Sivin (1973) chose what the Chinese call "rényào" 人藥 "human drugs" as a pilot experiment sample for pharmacologically analyzing the efficacy of drugs used in TCM. In contrast to many traditional Chinese plant, animal, and mineral pharmaceuticals with uncertain active constituents, the chemical composition of the human body and parts is well known, and "their therapeutic effectiveness, or lack of it, can be objectively, if approximately,