Lungs. Two spongy organs in the thorax, entered by the bronchi with their bronchial tubes; they contain in the walls of their air cells the capillaries through which the blood passes from the branches of the pulmonary artery to the branches of the pulmonary veins.
Rec'tum. The lowest and last section of the alimentary canal, being the discharge pipe of the large intestine, and excreting the solid wastes in the form of the feces.
Res pi ra'tion. Breathing; the action of the body by which carbon dioxid is given off from the blood and a corresponding amount of oxygen is absorbed into the blood.
Skin. The continuous outer covering of the body, in the deeper layer (der'ma) of which are located the sweat glands, which secrete sweat (a watery, oily substance containing impurities from the blood) and excrete it through the sweat ducts and their openings (pores) in the surface of the skin.
Tra'che a (or trā chē' ȧ). The windpipe between the larynx and the bronchi.
U'ri na ry system. The organs concerned in the secretion and discharge of urine: the kid'neys (two glands in the abdominal cavity, back of the peritoneum, which receive wastes from the blood, and excrete them as urine), the u re'ters (ducts through which the urine flows from the kidneys to the bladder), the blad'der (an elastic muscle-sac in which the urine is retained until discharged from the body).
VI. Relating to the Nervous and Motor Systems
Brain. The soft mass of nerve tissue filling the upper cavity of the skull. Its cellular tissue is gray, and its fibrous tissue white. With the spinal cord it controls all the sensory and motor activities of the body.
Cer e bel'lum. The part of the brain lying below the hind part of the cerebrum.