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 muscular and focuses on the exterior of the body, what can be see and felt. This was the standard of beauty of humans and continues to be the ideal body of European traditions. There is no Vitruvian women. Eastern ideologies of the body explain what can be detected, not only felt and examined. This comes from the idea that there is not only what can be physically seen and touched but what can't be. Energy or more aptly the means by which your body can manifest itself in the world can't be seen but, was thought to be able to