Respiratory, digestive and musculo-skeletal systems
Identify the anatomy of the digestive system
Digestion is the process which turns food which is consumed into the energy needed to survive. The digestion process also involves creating waste to be eliminated.
The digestive tract is a long winding tube that begins in the mouth and ends at the anus. It is made up of a series of muscles that coordinate the movement of food and other cells that produce enzymes and hormones to aid in the breakdown of food. Along the way are three very important organs that are needed for digestion, they are the liver, gallbladder, and the pancreas.
Stated below is the proccess of which happens when food enters the mouth.
Mouth: Teeth bite off and chew food into a soft pulp that is easy to swallow. The chewing mixes the food with saliva, from the six salivary glands around the mouth and face to make it moist enough to travel.
Oesophagus: The oesophagus, is a muscular tube. It takes food from the throat and pushes it down through the neck, and into the stomach. It moves food by waves of muscle contraction called peristalsis.
Stomach: The stomach has thick muscles in its wall. These contract to mash the food. The stomach lining produces strong digestive juices. These chemically attack the food, breaking down and dissolving its nutrients.
Pancreas: The pancreas, like the stomach, makes powerful digestive juices called enzymes which help to digest food further as it enters the small intestines.
Gall Bladder: This small bag like part is tucked under the liver. It stores fluid called bile, which is made in the liver. As food from a meal arrives in the small intestine, bile flows from the gall bladder along the bile duct into the intestine. It helps to digest fatty foods and also contains wastes for removal.
Small Intestines: This part of the tract is narrow, but very long - about 20 feet. Here, more enzymes continue the chemical attack on the food. Finally the nutrients are small enough to pass through the lining of the small intestine, and into the blood. They are carried away to the liver and other body parts to be processed, stored and distributed.
Liver: Blood from the intestines flows to the liver, carrying nutrients, vitamins and minerals, and other products from digestion. The liver stores nutrients, changes them from one form to another, and releases them into the blood according to the activities and needs of the body.
Large Intestine: Any useful substances in the leftovers, such as spare water and body minerals, are absorbed through the walls of the large intestine, back into the blood. The remains are formed into brown, semi-solid faeces, ready to be removed from the body.
Rectum and Anus: The end of the large intestine and the next part of the tract, the rectum, store the faeces. These are finally squeezed through a ring of muscle, the anus, and out of the body.
Explain how the processes of indigestion, digestion, absorption, assimilation, and egestion relate to the anatomy of the gastro-intestinal tract.
The gastrointestinal tract is a single tube approximately nine metres long when its relaxed. It is open at each end, to the mouth and the anus, it incldes several regions, the oral cavity, pharynx, oesophagus, stomach, small and large intestines, rectum and anal canal. Various accessory digestive organs open into the tract and there are a number of sphincters and valves. Food that is in the GI tract is not really inside the body, to enter the body food must be broken down and enter the lymphatic system.
Marieb (2005) describes the digestive tract as a “disassembly line” carrying food from one stage to the other so that I can be broken down and absorbed into the body. The stages involved in this breakdown process are ingestion, mastication, mechinal digestion (chewing) chemaical digestion, absorption into the blood and lympth, assimilation