Week 5: GI Anatomy Review Flashcards
What is the structure of the Gastrointestinal system?
consists of the GI tract and related solid organs of digestion (esophagus, pharynx, mouth, stomach, gallbladder, pancreas. colon, small intestine, liver, rectum, anus)
What is the 3 main functions of the GI system?
- provide nutrients for the body
- secretion of digestive juices
- absorption of nutrients
What facilitates the movement of food through the esophagus?
- secretion of mucus
- very strong muscle movement to propel food
What is esophageal sphincters?
bundle of muscles that are normally closed at rest
What does the upper esophageal sphincter do?
prevent food from being aspirated into the lungs
What does the lower esophageal sphincter (AKA cardiac sphincter) do?
separates the esophagus from the stomach to prevent acidic contents of the stomach from entering back into the esophagus
What is the normal capacity of the stomach?
1000-1500mL
What 3 things do the gastric glands secrete?
- HCl
- intrinsic factor
- gastrin
What are the layers of the stomach?
Mucosa layer (inner layer), two muscle layers, and serosa (outer layer)
What makes up the mucosa layer of the stomach?
G-cells, parietal, chief and epithelial cells
What does the two muscle layers of the stomach do?
help propel from from the stomach to small intestine
What does G-cells do?
produce gastrin, a hormone that facilitates production of HCl
What does parietal cells do?
produce HCl to breakdown food, and Intrinsic Factor to protect the mucosa
What does Chief cells do?
secrete pepsin
What does the epithelial cells of the stomach do?
secrete bicarbonate rich solution to coat and protect mucosa
What are the three sections of the small intestine? IN ORDER
duodenum, jejunum, and ileum
What is plicae circulares?
The circular folds of the mucous membrane that makes up the entire inner wall of the small intestine
What is intestinal villi?
finger like projections on the plicae circulares
What is microvilli?
microscopic projections on each intestinal villi
What special cells are in the small intestine?
Crypts of Lieberkuhn, goblet cells, and brunner glands
What does crypts of lieberkuhn do?
secrete about 2L of fluid a day into lumen of intestine, which is quickly reabsorbed by the villi
What do goblet cells and brunner glands do?
secrete large amounts of mucus to protect the small intestine from acidic gastric juices
What is the ileocecal sphincter?
the area where food passes from the small to the large intestine
What is the turnover of the small intestine?
48-72hrs
What is included in the large intestine?
appendix, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum
What is the turnover of the large intestine cells?
3-8days
What allows for motility of the GI tract?
contraction of 2 layers of smooth muscle
What are the two types of GI motility?
propulsive and mixing
What regulates GI motility?
enteric nervous system, autonomic nervous system, and hormones
What is the function of the esophagus?
transport food
What is the function of the stomach?
- stores and churns food
- Pepsin digests proteins
- HCl activates enzymes, breaks up food and kills germs
What is the function of the small intestine?
completes digestion, absorbs nutrients.
peptidase digests protein, sucrases digest sugars and amylase digests polysaccharides
What is the function of the large intestine?
reabsorbs some water and ions, forms and stores feces
What is the function of the rectum?
sore and expel feces
