The heart is a pumping system which takes in deoxygenated blood through the veins and delivers it to the lungs for oxygenation before pumping it into the various arteries (which provide oxygen and nutrients to body tissues by transporting the blood throughout the body).he cardiovascular system of the head and neck includes the vital arteries that provide oxygenated blood to the brain and organs of the head, including the mouth and eyes. It also includes the veins that return deoxygenated blood from these organs to the heart.
the part of the alimentary canal extending from the pyloric opening of the stomach to the anus. It is a membranous tube, comprising the small intestine and large intestine; called also bowel and gut. See also intestinal tract, and see color plates.
Absorption is the movement of digested food molecules through the wall of the intestine into the blood or lymph. The small intestine is the region where digested food is absorbed. Most absorption happens in the ileum. This is the longest part of the small intestine and is between 2-4 metres long. The small intestine has a large internal surface area for absorption to happen quickly and efficiently.