Читать книгу The Body at Work: A Treatise on the Principles of Physiology онлайн

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The thoracic duct provides for the overflow of lymph from the spaces of the body. There is no circulation of lymph. Lymph from the liver and from the intestines is constantly draining into the thoracic duct, and thus returning to the blood-stream by a short direct route, entering it without the necessity for reabsorption through the walls of capillary vessels. By no means all of this fluid has exuded from the blood-stream. Much of it is water which was poured into the stomach as gastric juice, and into the intestines as the secretions of the pancreas and other glands, or imbibed through the mouth and absorbed by the lymphatics of the alimentary canal. The remainder of the water taken up from the alimentary canal enters its bloodvessels. The diluted blood flows to the liver, loaded with digested products which the liver will store. As the blood parts with them the additional water which has served for their transport exudes from the capillaries of the liver into lymphatics, which empty it into the thoracic duct. Large quantities of water are used in washing out digested products. Secreted into the alimentary canal by the digestive glands, it passes out through its wall as the vehicle of digested products. Collected by lymphatic vessels, it is either carried directly into the thoracic duct, or passed from lymph into blood, carried by blood to the liver, again transferred from blood to lymph, and borne by the lymphatic vessels of the liver to the thoracic duct.