ANATOMY AND PHYSIOLOGY OF THE DIGESTIVE SYSTEM
The digestive system is basically a tube running through the body from the mouth to the anus. The organs of the digestive system include the oral cavity (mouth), esophagus, stomach, small and large intestine and rectum. Their role is to break down food and deliver the products to the blood for dispersal to the body cells. The undigested food that remains in the tract leaves the body through the anus as feces. The break down activities that begin in the mouth are completed in the small intestine. From that point on, the major function of the digestive system is to reclaim water. The liver is considered to be a digestive organ, because the bile it produces helps to break down fats. The pancreas which delivers digestive enzymes to the small intestine, also in functionally a digestive organ.
The process of digestion begins in the mouth where food is chewed until it reaches a consistency whereby it can be swallowed. The following accessory structures aid this early stage of digestion: Tongue — a muscle that is covered by taste buds. It assists the process of chewing and man oeuvres food to a position where it can be swallowed easily. Salivary glands — begin the process of chemical digestion through the secretion of the enzyme, salivary amylase. This enzyme begins the process of breaking down carbohydrates. Saliva also moistens food which helps it to be swallowed more easily. Teeth — break food down mechanically into smaller particles that may be ingested more easily. Pharynx — allows the passage of both food and air.
Esophagus — tube that leads to the stomach.
The esophagus is the tube or gullet connecting the mouth to the stomach. It lies in front of the vertebral column and behind the trachea (breathing tube) and heart. Stomach
Food remains in the stomach for 3 to 4 hours. During this time it is further broken down by the muscular churning action of the stomach. Powerful gastric...
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