Alimentary tract function Flashcards
What does the Gi refers to:
- esophagus
- stomach
- intestines
What does the upper GI include:
- Esophagus
- Stomach
- Duodenum
What does the lower GI include:
- Small intestine
- Large intestine
What are the major processes occuring in the GI tract?
- Motility
- Secretion
- Regulation
- Digestion
- Absoption
What are the GI hormones:
- gastrin
- cholecytokinin (CKK)
- secretin
- glucose-dependent insulin tropic polypeptide (gastric inhibitory polypeptide; GIP)
Where does MOST of the digestion and absorption take place?
In the small intestine
What get absorbed in the stomach?
Medium-chain fatty acids and some drugs. Proteins and fat too.
What are the specialised epithelial cells in the small intestine that take up the digested products of nutrients for transport into either the portal circulation or the lymphatic system called?
Enterocytes
Where are the enterocytes found?
In the small intestine
What increases the surface area for uptake from the lumen of the small intestine?
The villi and brush border membrane of the enterocytes.
What facilitates the digestion and absorption in the GI tract?
Secretions from the:
- salivary glands
- stomach
- pancreas
- liver
What are the two primary function of the secretory glands?
- FIRST, digestive enzymes are secreted from the mouth to the small intestine to break down food.
- SECOND, glands secrete mucus for lubrication and protection.
Does the secretion of mucus play a prominent role in the immune system?
Yes
What two types of protein secretion does the salivary glands produce?
- Serous cells: produce secretion containing amylase, an enzyme that breaks down starch
- mucous cells: produce mucin for lubrication and protection
What enzyme that breaks down starch?
Amylase
What functions does saliva have?
- facilitate chewing and swallowing by lubricating food
- carries immunoglobulins that combat pathogens
- assis in carbohydrate digestion
What is salivon?
Salivon is the basic unit of the salivary gland.
What forms the salivon?
The acinus and associated ductal system form the salivon
What three phases does the gastric secretion occur in?
- The cephalic phase
- The gastric phase
- The intestinal phase
What is the main gastric enzyme in protein digestion?
pepsin
What controls the gastric secretion?
Gastric secretion is under neuronal and hormonal control
What inhibit gastric secretion?
Gastric secretion is inhibited by gastric hormones:
- somatostatin
- secretin
- gastric inhibitory peptide
Where are pancreatic enzymes produced?
in the aciar cells
What are the pancreatic secretions rich in?
bicarbonate ions
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What cause the release of secretin?
The presence of acid in the duodenum cause the release of secretin.
What cause the relese of Cholecytokinin?
The presence of fats in duodenum cause the relese of Cholecytokinin.
What cause the release of pancreatic enzymes?
Vagal stimulation cause the release of pancreatic enzymes.
What cause the release of bicarbonate secretion?
Secretin causes the release of bicarbonate secretion.
CCK causes the release of enzymes.
What produces the bile?
the hepatocytes (cells of the liver)