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
Catholic theology of the body creation of God. God created the body like a work of art in his image. This creation reflects God’s intelligence. The human body is (eikon) somehow similar to God. To be completed as a mirror of him, is the task for every Christian. Unlike the human body, the soul is an image of God. The body cannot be an image of God, otherwise God would look like a human being with a human body. Only the soul can see God, but it is caught between the flesh and spirit. It constantly has to make a choice between the two. Origen