GI tract Flashcards
What is the function of the oral cavity?
Chewing reduces food into smaller particles. The saliva contains amylas that degrades starch through hydrolysis and the saliva also lubricates the bolus making it easier to swallow.
What is the function of the esophagus?
To swallow food and make sure it goes down and not in your lungs and not upwards through it’s 2 sphincters. The upper sphincter that is skeletal muscle and the lower that is a sheet of smooth muscle and then the diaphragm that is skeletal muscles responsible for our breathing will contract around the esophagus and act as a sphincter.
What is the function of the fundus?
To churn food and hydrolyse them to make chyme and to store the chyme.
How can the small intestines be divided?
Dodeunum, jejenum, illeum.
What are the general function of the large intestine?
Absorbtion of water, ions, vitamin K,
What is the general function of the rectum?
Storage
What is the general function of the anus?
Expulsion
How can the stomach store so much food and then go back to such a small size?
It has folding of the gastric wall which enabled it to stretch out to become smooth and give a larger surface area to secrete enzymes.
What is the brush boarder?
The surface of the small intestines that are covered in small vili that is covered in small microvili that gives a larger surface area for secretion of enzymes and absorbtion. The brush boarder in the doedeunum has a coat of many important enzymes that digest food or active other enzymes.
What is the anatomy of the Hepa?
The hepa is made out of multiple lobes called hepatic lobule. In these lobules there are lots of hepatocytes and surrounded in a 6 edged ring fashion there are the portal triad. The portal triad is the common hepatic duct, the proper hepatic artery and the portal vein. The common hepatic duct is where bile leaves the hepa, the proper hepatic artery supplies the hepatocytes with oxygen. The portal vein supplies the hepatocytes with nutrient rich food from the intestinal tract. Then all the blood from the hepa will leave through the central vein.
What is the billary tree and how does it work?
Bile are made out of bile pigments and bile salts. The bile salts emulsiftise fat. The bile from the hepa goes through the common hepatic duct and goes through the cystic duct and goes into the gallbladder to be stored. CCK is a hormone that will cause the gallbladder to contract to release bile to go back through the cystic duct and through the common bile duct it enters the duodenum then it travels along to the illeum where it is absorbed and travels back to the hepa to be reused.
What is the anatomy of the pancreas?
It sits in the retroperoteneum which means it sits back in the abdomen. It can be divided into the exocrine pancrease that releases salts and enzymes into the dodeunum and the endocrinic pancreases that releases hormones into the blood stream.
What is the anatomy and function of the colon, rectum and anus?
The colon can be divided into many smaller parts and it’s function is to absorb water and inorganic ions such as sodium and potassium. It also has lots of microorganisms that are important for the digestion of nutrients especially carbohydrates.
The rectum is responsible for storage and the anus has the internal and external anal sphincter. The internal are smooth muscle and the external are skeletal muscles.
How will chyme regulate the GI system?
Chyme gets delivered to the dodeunum which triggers a release of secretin that goes to the pancreas and that release bicorbanate rich solutions that will neutralise the acid from the stomach. The secretin also goes back to the fundus that will inhibit stomach motility and acid release. Chyme will also trigger the release of CCK, that goes to the pancreas that trigger release of pancreatic enzymes that helps the digestive process, such as lipase, and CCK also goes to the gallbladder and cause the gallbladder to contract so it releases bile. CCK also goes to the fundus and decrease stomach motility so the body has time to digest the food. The nutrient from the chyme that triggers CCK to be released is fat. And the secretin is triggered by a low pH.
What are some important parts of the GI system that isn’t organs?
Immune system, nervous system, hormones, microbes.