Gi tract overview Flashcards
What is the primary function of the digestive system?
Digestion of food & absorption of nutrients
What are the main processes involved in digestion?
- Ingestion
- Motility (propulsion)
- Secretion
- Digestion (mechanical & chemical)
- Absorption
- Elimination/defecation
What is the role of the serosa in the gastrointestinal tract?
Outermost layer that protects the GI tract when it moves
What is the innermost layer of the gastrointestinal tract called?
Mucosa
What types of cells are found in the mucosa?
- Epithelial cells
- Exocrine cells
- Endocrine cells
- Enteroendocrine cells
What is the function of the muscularis externa?
Responsible for segmentation and peristalsis
What does the enteric nervous system (ENS) consist of?
Two plexuses: submucosal and myenteric
How does acetylcholine affect smooth muscle in the gastrointestinal tract?
- Increases smooth muscle tone & activity
- Relaxes sphincters
- Stimulates secretory activity
True or False: The esophagus has absorptive and digestive functions.
False
What are the three main functions of the stomach?
- Temporary storage for food
- Mixing/digestion of food
- Regulates release of gastric contents
What is the role of gastric pits and glands?
Secrete enzymes and other molecules for digestion and protection
What are the three divisions of the small intestine?
- Duodenum
- Jejunum
- Ileum
What increases the absorptive function of the small intestine?
- Permanent circular folds (plicae circulares)
- Villi
- Microvilli (brush border)
What is the primary function of the large intestine?
Absorption of remaining water, vitamins, and excretion of indigestible substances
Fill in the blank: The _____ is responsible for churning and emptying of food in the stomach.
[pyloric region]
What is the function of saliva?
- Protection
- Lubrication
- Initial digestion of starches and lipids
- Taste
What is the primary function of the gallbladder?
Stores bile
What is segmentation in the small intestine?
Slow contractions that mix chyme and digestive enzymes
What triggers peristalsis in the esophagus?
Stretch of the bolus
What is the role of the pyloric sphincter?
Regulates the exit of chyme from the stomach to the duodenum
What is the composition of the bacterial microbiota in the large intestine?
Consists of >1000 different types of bacteria
What is the term for the rhythmic propulsive movements in the small intestine?
Peristalsis
What are the five divisions of the large intestine?
- Caecum
- Appendix
- Colon (ascending, transverse, descending, sigmoid)
- Rectum
- Anal canal
What is the primary function of the pancreas in digestion?
Secretes digestive enzymes into the small intestine
