dygestiv sys 2 Flashcards
What are the three phases of swallowing?
Buccal (voluntary), pharyngeal, and esophageal (involuntary).
What are the four main functions of the stomach?
Food storage, mechanical breakdown, disruption of chemical bonds, and production of intrinsic factor.
What is chyme?
A semi-fluid mixture of food and gastric secretions formed in the stomach.
Which cells secrete hydrochloric acid in the stomach?
Parietal cells.
Which stomach cells secrete the precursor to pepsin?
Chief cells.
What is the role of enteroendocrine (G) cells in the stomach?
They secrete gastrin, which stimulates chief and parietal cells.
What stimulates the cephalic phase of gastric activity?
Sight, smell, taste, or thought of food, via the vagus nerve and CNS.
What happens during the gastric phase of digestion?
Stomach distension, increased pH, and undigested food stimulate acid and enzyme secretion.
What triggers the intestinal phase of gastric regulation?
Arrival of chyme in the small intestine.
Which hormones are released in the intestinal phase?
Secretin, CCK, and GIP (inhibit stomach activity).
What is the primary function of the small intestine?
Most digestion and absorption of nutrients, water, vitamins, and ions.
List the three segments of the small intestine in order.
Duodenum, jejunum, ileum.
Where are pancreatic enzymes and bile released?
Into the duodenum.
What are the primary roles of bile?
Emulsifies fats and aids lipid uptake.
Which pancreatic enzymes aid digestion?
Amylase (carbs), proteases (proteins), lipases (fats), nucleases (nucleic acids).
How are pancreatic proteases activated?
They are secreted as inactive proenzymes and activated in the intestine.
What is the function of the large intestine?
Absorbs water and ions, stores indigestible material and bacteria until elimination.
What does gastrin do?
Stimulates gastric acid production in the stomach.
What does secretin do?
Stimulates release of water and bicarbonate to neutralize chyme; promotes bile production.
What is the function of cholecystokinin (CCK)?
Stimulates bile release, pancreatic enzyme secretion, and reduces appetite.
What is the function of vasoactive intestinal peptide (VIP)?
Increases blood flow to the intestine and inhibits stomach acid production.
What is Ozempic and how does it work?
It’s a GLP-1 agonist that promotes insulin release, reduces glucagon, and helps control appetite and weight.
What advantage does semaglutide (Ozempic) have over natural GLP-1?
It has a longer half-life (~1 week) due to chemical modifications that make it resistant to degradation.
Which intestinal cells absorb nutrients?
Enterocytes.
