Human body include the heart, lungs and liver. Many organs reside within cavities within the body. These cavities include the abdomen and pleura. The circulatory system comprises the heart and blood vessels (arteries, veins and capillaries). The heart propels the circulation of the blood, which serves as a "transportation system" to transfer oxygen, fuel, nutrients, waste products, immune cells and signalling molecules (i.e., hormones) from one part of the body to another. The blood consists of fluid that carries cells in the circulation, including some that move from tissue to blood vessels and back, as well as the spleen and bone marrow.
Catholic theology of the body communicate with him. The human body is the lower element of the human person. Through the body, man experiences his temporal existence. But Gregory also admired human beauty and the bodily abilities to dream, sleep and memorize. The body can be both a friend and enemy of a person, according to Gregory. The final goal is a unity of the soul with God, which is possible with Grace and the assistance of the Holy Spirit according to Gregory. Gregory of Nyssa (335-394) was a bishop who wrote, among others, about the creation of the human body. Unlike Irenaeus, Gregory states,