Final Exam 5 Flashcards
What does the GI tract provide the body with?
water, electrolytes, and nutrients
What controls the GI system?
The nervous and endocrine systems
What are the main 4 functions of the GI tract?
- Movement of food through the system
- Secretion of digestive juices, digestion of food
- Absorption of digestive products, water, elytes
- Circulation of blood through digestive organs to carry away absorbed substances
What are the parts of the GI tract?
Mouth, esophagus, stomach, duodenum, jejunum, illeum, colon
What makes up the duodenum?
pancreas, liver, and gallbladder
Where is the sphincter?
The lower end of the esophagus (circular muscle)
What is the function of the sphincter?
prevents reflux of gastric acid into esophageal lumen
What is the process when food goes down the esophagus?
When peristaltic wave passes down esophagus, sphincter relaxes to allow propulsion of food into stomach
What are the parts of the stomach?
The body and antrum
What are the three motor functions of the stomach?
- Storage of large amounts of food
- mixing of food with gastric secretions to for chyme
- Slow emptying of chyme into SI
How are digestive juices made?
They are secreted by the gastric glands which cover the body of the stomach
What happens when the stomach contains food?
- When the stomach contains food, weak peristaltic waves occur every 15-20 sec
- Become stronger and push food towards the pylorus (pyloric sphincter = distal opening of stomach
What is chyme?
The mixture of food and gastric secretions; its a semi-fluid
What is the pH of the stomach?
1.5-3.5
What is the function of the small intestine?
Mixing contractions and propulsive contractions (peristaltic waves), also chops chyme
When do propulsive contractions occur and what happens?
- Increases a lot after meal
- Chyme is pushed to the ileocecal valve; spread out along mucosa
What happens when a portion of the SI is distended with chyme?
The SI stretches and elicits localized contractions
What is the function of the villus?
Increased surface area for absorption of nutrients in the small intestine
What is released after eating something like a donut?
insulin
Where is insulin digested and then where does it go?
Digested in the stomach and intestines, then it is absorbed into the blood
What happens when insulin is released?
Causes rapid uptake, storage and use of glucose by tissues in body, especially muscles, adipose tissue and liver
How is the majority of hormones controlled?
Negative feedback
What causes the release of hormones?
A stimulus
What is the largest organ IN the body?
The liver
