Monday, April 5, 2010
Sunday, April 4, 2010
Gastrointestinal System
The topic that I’ll be going discuss is all about gastrointestinal system or so called digestive system. We always wonder how food circulates in our body. In this selection you’ll understand how digestive system works, what are its parts and how does it process.
Digestive system begins with the digestive tract, a muscular tube which contains the organs of digestive system. It has different parts namely mouth, pharynx, esophagus, stomach, small and large intestine, and anus. It also has accessory organs which are liver, salivary glands, gall bladder, pancreas and teeth.
Digestive process starts with the food enters the mouth, ingestion. After ingestion, mastication or the chewing action is the next process. Then, digestion or the chemical process of breaking down the food occurs followed by secretion of acids, buffers, enzyme and water. After that, excretion of waste products and unusable material happens.
The first part of the digestive system is the mouth or buccal cavity which is the opening. It contains lips or labia which is the door to its chamber, tongue that acts as the floor, and tongue base and uvula which is the boundary between oral cavity and next part of digestive system.
The next part is the tongue, a muscle that provides taste, stimuli temperature and texture, it also manipulates food while chewing and aids in swallowing. Salivary glands are 99.4% of water and contain antibodies, buffers, ions, and waste. It has 3 types, the parotid, sublingual, and submandibular.
After that are the teeth. The teeth have 2 categories, the deciduous or baby teeth and permanent teeth. There are different types of teeth, the Incisor which is located at the front and used for cutting, the canine teeth also known as cuspids which holds, tears, and slash the food, the bicuspids which are the transitional teeth, and lastly the molar which is the final teeth used for crushing and grinding the food. It also has three parts, the crown which is the visible part, the neck, and the root. It is composed of dentin, pulp, and cementum.
Next is the pharynx which is already discussed in my previous post. Followed by the pharynx is the esophagus. Esophagus is approximately 10 inches. It transports food from the pharynx to the stomach. It also contains loose layer of connective tissue called adventitia. It has different parts, pharyngoesophageal sphincter and lower esophageal sphincter. Peristalsis is the rhythmic muscular contraction which moves bolus through esophagus.
There are different walls of the alimentary canal. The outermost layer is the serosa. It is composed of a single thin layer of flat serous fluid-producing cells. Next is the muscularis externa which is composed of two layers of smooth muscles. After that is submucosa, it is composed of connective tissue that contains blood vessels and lymph nerve endings. Then the next layer is mucosa, which is composed of two layers of epithelium. Retroperitoneal organs are not surrounded by peritoneum.
After the esophagus is the stomach which is located in the left abdominal cavity under the diaphragm and it is covered almost completely by the liver. It acts as a temporary holding for received foods, secretes gastric acid and enzymes, regulates the rate at which chime enters the small intestine, and absorbs small amount of water and substances. Stomach has four regions: the cardiac region, fundus, body, and pylorus. Gastric juice has different production phases: the cephalic phase, gastric phase, and intestinal phase.
The seventh part is the small intestine that is located in the central lower abdominal cavity. It is the major organ of digestion. It has 3 regions: the duodenum, jejunum, and ileum. There are hormones produced by the small intestine namely secretin which secretes duodenum and stimulates the release of bicarbonate and water. The next hormone is the gastrin which secretes stomach and stimulates the release of gastric juices. Lastly is the cholecystokinin, which stimulates gall bladder.
After the small intestine is the large intestine which reabsorbs water and absorbs vitamin produced by normal bacteria, it also packages and compacts waste products. Like the other parts, it also have regions namely cecum and rectum.
The topic was somehow boring because there were so many discussions. Conrad was the reported so expect an extreme lesson. We had a check up quiz which I passed.
Digestive system begins with the digestive tract, a muscular tube which contains the organs of digestive system. It has different parts namely mouth, pharynx, esophagus, stomach, small and large intestine, and anus. It also has accessory organs which are liver, salivary glands, gall bladder, pancreas and teeth.
Digestive process starts with the food enters the mouth, ingestion. After ingestion, mastication or the chewing action is the next process. Then, digestion or the chemical process of breaking down the food occurs followed by secretion of acids, buffers, enzyme and water. After that, excretion of waste products and unusable material happens.
The first part of the digestive system is the mouth or buccal cavity which is the opening. It contains lips or labia which is the door to its chamber, tongue that acts as the floor, and tongue base and uvula which is the boundary between oral cavity and next part of digestive system.
The next part is the tongue, a muscle that provides taste, stimuli temperature and texture, it also manipulates food while chewing and aids in swallowing. Salivary glands are 99.4% of water and contain antibodies, buffers, ions, and waste. It has 3 types, the parotid, sublingual, and submandibular.
After that are the teeth. The teeth have 2 categories, the deciduous or baby teeth and permanent teeth. There are different types of teeth, the Incisor which is located at the front and used for cutting, the canine teeth also known as cuspids which holds, tears, and slash the food, the bicuspids which are the transitional teeth, and lastly the molar which is the final teeth used for crushing and grinding the food. It also has three parts, the crown which is the visible part, the neck, and the root. It is composed of dentin, pulp, and cementum.
Next is the pharynx which is already discussed in my previous post. Followed by the pharynx is the esophagus. Esophagus is approximately 10 inches. It transports food from the pharynx to the stomach. It also contains loose layer of connective tissue called adventitia. It has different parts, pharyngoesophageal sphincter and lower esophageal sphincter. Peristalsis is the rhythmic muscular contraction which moves bolus through esophagus.
There are different walls of the alimentary canal. The outermost layer is the serosa. It is composed of a single thin layer of flat serous fluid-producing cells. Next is the muscularis externa which is composed of two layers of smooth muscles. After that is submucosa, it is composed of connective tissue that contains blood vessels and lymph nerve endings. Then the next layer is mucosa, which is composed of two layers of epithelium. Retroperitoneal organs are not surrounded by peritoneum.
After the esophagus is the stomach which is located in the left abdominal cavity under the diaphragm and it is covered almost completely by the liver. It acts as a temporary holding for received foods, secretes gastric acid and enzymes, regulates the rate at which chime enters the small intestine, and absorbs small amount of water and substances. Stomach has four regions: the cardiac region, fundus, body, and pylorus. Gastric juice has different production phases: the cephalic phase, gastric phase, and intestinal phase.
The seventh part is the small intestine that is located in the central lower abdominal cavity. It is the major organ of digestion. It has 3 regions: the duodenum, jejunum, and ileum. There are hormones produced by the small intestine namely secretin which secretes duodenum and stimulates the release of bicarbonate and water. The next hormone is the gastrin which secretes stomach and stimulates the release of gastric juices. Lastly is the cholecystokinin, which stimulates gall bladder.
After the small intestine is the large intestine which reabsorbs water and absorbs vitamin produced by normal bacteria, it also packages and compacts waste products. Like the other parts, it also have regions namely cecum and rectum.
The topic was somehow boring because there were so many discussions. Conrad was the reported so expect an extreme lesson. We had a check up quiz which I passed.
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