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 manuscript is recorded in the Yellow Emperors Inner Cannon, and it being recorded in this way represents the attention to the individuals perspective in creating therapies like acupuncture to treat body ailments. The Inner Cannon was revised by natural Philosophers of the time and the approved version of the Han Court and became a foundational text for the ideals and perceptions of the human body. It focused on Qi, Yin and Yang balance, and Five phase theory to explain health can disease. Referred to as the life force of the body, or the means by which the body is able