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
Theology of the Body original design for human sexuality and thus the dignity of the human person, how it was distorted through sin, and how it has been restored and renewed through the redemption of Jesus Christ; and Catholic teachings about the sacramentality of marriage. The central thesis of John Paul's Theology of the Body, according to author Christopher West, is that "the body, and it alone, is capable of making visible what is invisible: the spiritual and the divine. It was created to transfer into the visible reality of the world, the mystery hidden since time immemorial in God, and thus to be