Stage Four of the Digestive System
In this stage of the digestive system, many organs start to work together. Digestion is not simply the process of breaking down food. It also is a process of filtering out poisons and toxins that might enter through food, and of absorbing nutrients into the bloodstream (Morrison, 2001). The organs involved in this process are the liver, the pancreas, the gall bladder, and the duodenum.
The liver is the largest organ not only of the digestive system, but the whole body. It is the size of a football and weighs around three pounds. It produces bile and has a lot of other functions to perform including digestion, metabolism, immunity, and the storage of nutrients (Taylor, 2013). Without the liver functioning properly, the cell body can die due to lack of nutrients. Liver is the storage facility for iron, vitamins, and glycogen. Glycogen is the storable form of glucose, the sugar that the body cells convert into energy. This energy is used between meals for all activity. The liver also removes poisons from the blood and converts them into safer elements. The livers compositions aids in performing these functions. It is made up of sponge like porous material which helps the blood pass through it to other organs of the digestive system. The liver cells are called hepatocytes that carry more than 500 functions but mainly they produce bile that travel to gallbladder for storage (Morrison, 2001).
The gallbladder is a muscular bag about three inches long, tucked behind the lobes of the liver. It stores the green liquid bile produced by the liver. As food moves towards the small intestine’s upper part, duodenum, the gallbladder contract, forcing the bile out into the bile duct. The bile duct joins the pancreatic duct. The bile enters the duodenum, through the duct, and mixes with food. Bile does not contain enzymes but chemicals called bile salts. These chemicals attack the fats in the food and breaks them down. The small broken down fat droplets are then attacked by the enzyme lipase which breaks down fats even further ( Walker & Wood, 2003).
The pancreas is another organ in this stage of digestion. It is a small organ, about six inches long and lies just behind the stomach. It has two functions. Firstly, it produces pancreatic juice, which it releases into the duodenum. Secondly, it produces a hormone called insulin, which it releases into the blood stream. The pancreatic juice contains many enzymes, which carry on the process of digestion. The enzymes are made by special cells called the acinar cells which are found in clusters like grapes. The pancreatic juice is collected in small tubes that eventually join together to form the pancreatic duct. The juice travels through this duct to reach the duodenum. The enzymes in the pancreatic juice are very strong and are produced in an inactive form as to not damage the pancreas. They become active when they reach the alkaline contents of the duodenum. There are three types of enzymes in pancreas. First there are trypsin and chymotrypsin. These enzymes break down proteins into smaller molecules. Then there is amylase, which splits starch and changes it into maltose. Lastly, there is lipase, which starts to digest fats, changes them into fatty acids and glycerol (Ballard, 1997). Production of insulin is the other important function of pancreas. The insulin is produced by small group of cells called islets of Langerhans. Insulin is released into bloodstream and taken to the liver. It plays an important role in controlling the sugar level in the blood (Ballard, 1997).
The liquid food leaves the stomach via pyloric sphincter, and enters the first part of the small intestine, the duodenum. It is shaped like a horseshoe and is about eight inches long (Kopf-Maier, 2004). It is made up of many longitudinal and circular muscular layers that contract and relax regularly to move food forward in the intestine. The proteins are broken down into smaller molecules called amino acids in the duodenum. Enzymes in the duodenum turn maltose and sucrose which are types of sugar that body can not use, into glucose, which the body can use. The digestive juices from liver and pancreas are mixed with the liquid food, and play an important part in the digestion of fats (Morrison, 2001).
In this stage of the digestive system, many organs start to work together. Digestion is not simply the process of breaking down food. It also is a process of filtering out poisons and toxins that might enter through food, and of absorbing nutrients into the bloodstream (Morrison, 2001). The organs involved in this process are the liver, the pancreas, the gall bladder, and the duodenum.
The liver is the largest organ not only of the digestive system, but the whole body. It is the size of a football and weighs around three pounds. It produces bile and has a lot of other functions to perform including digestion, metabolism, immunity, and the storage of nutrients (Taylor, 2013). Without the liver functioning properly, the cell body can die due to lack of nutrients. Liver is the storage facility for iron, vitamins, and glycogen. Glycogen is the storable form of glucose, the sugar that the body cells convert into energy. This energy is used between meals for all activity. The liver also removes poisons from the blood and converts them into safer elements. The livers compositions aids in performing these functions. It is made up of sponge like porous material which helps the blood pass through it to other organs of the digestive system. The liver cells are called hepatocytes that carry more than 500 functions but mainly they produce bile that travel to gallbladder for storage (Morrison, 2001).
The gallbladder is a muscular bag about three inches long, tucked behind the lobes of the liver. It stores the green liquid bile produced by the liver. As food moves towards the small intestine’s upper part, duodenum, the gallbladder contract, forcing the bile out into the bile duct. The bile duct joins the pancreatic duct. The bile enters the duodenum, through the duct, and mixes with food. Bile does not contain enzymes but chemicals called bile salts. These chemicals attack the fats in the food and breaks them down. The small broken down fat droplets are then attacked by the enzyme lipase which breaks down fats even further ( Walker & Wood, 2003).
The pancreas is another organ in this stage of digestion. It is a small organ, about six inches long and lies just behind the stomach. It has two functions. Firstly, it produces pancreatic juice, which it releases into the duodenum. Secondly, it produces a hormone called insulin, which it releases into the blood stream. The pancreatic juice contains many enzymes, which carry on the process of digestion. The enzymes are made by special cells called the acinar cells which are found in clusters like grapes. The pancreatic juice is collected in small tubes that eventually join together to form the pancreatic duct. The juice travels through this duct to reach the duodenum. The enzymes in the pancreatic juice are very strong and are produced in an inactive form as to not damage the pancreas. They become active when they reach the alkaline contents of the duodenum. There are three types of enzymes in pancreas. First there are trypsin and chymotrypsin. These enzymes break down proteins into smaller molecules. Then there is amylase, which splits starch and changes it into maltose. Lastly, there is lipase, which starts to digest fats, changes them into fatty acids and glycerol (Ballard, 1997). Production of insulin is the other important function of pancreas. The insulin is produced by small group of cells called islets of Langerhans. Insulin is released into bloodstream and taken to the liver. It plays an important role in controlling the sugar level in the blood (Ballard, 1997).
The liquid food leaves the stomach via pyloric sphincter, and enters the first part of the small intestine, the duodenum. It is shaped like a horseshoe and is about eight inches long (Kopf-Maier, 2004). It is made up of many longitudinal and circular muscular layers that contract and relax regularly to move food forward in the intestine. The proteins are broken down into smaller molecules called amino acids in the duodenum. Enzymes in the duodenum turn maltose and sucrose which are types of sugar that body can not use, into glucose, which the body can use. The digestive juices from liver and pancreas are mixed with the liquid food, and play an important part in the digestion of fats (Morrison, 2001).