Trachea Diffusion of oxygen and carbon dioxide takes place across the walls of the smallest tubes, called tracheoles, which penetrate tissues and even indent individual cells. Gas may be conducted through the respiratory system by means of active ventilation or passive diffusion. Unlike vertebrates, insects do not generally carry oxygen in their haemolymph. This is one of the factors that may limit their size. A tracheal tube may contain ridge-like circumferential rings of taenidia in various geometries such as loops or helices. Taenidia provide strength and flexibility to the trachea. In the head, thorax, or abdomen, tracheae may also be connected
History of beliefs about the human body as Traditional chinese medicine, or western, which follows the Greek traditions of science and is more closely related to modern science despite original anatomists and ideas of the body being just as unscientific as Chinese practices. In Western historical research, scholars began investigating the cultural history of the human body in detail in the 1980s. The movement is particularly associated with the historian of medicine Roy Porter, whose 1991 article 'History of the Body' was a seminal study. 1995 saw the foundation of the journal "Body and Society", by which time the field of the history of the body was