Gut Secretion, Control, Motility, Emptying Flashcards
What is the first exocrine product of the GIT?
Saliva
How is saliva production controlled?
Both parasympathetic and sympathetic nervous systems
Is salivation conditioned or unconditioned?
Both
What are the major roles of saliva?
Lubrication (Primary), keeping mouth clean, taste (Dissolves food which collects in ducts around taste buds, amylase), pheromones in saliva
How is peristaltic activity of the esophagus stimulated?
Presence of a bolus of food at the top of the esophagus triggers reflex peristaltic activity
What do the cardia, body, and antrum secrete?
Cardia: Mucus bicarbonate
Body: HCl, pepsin, intrinsic factor, mucus
Antrum: Gastrin and mucus
What are the phases of gastric secretion?
Cephalic: Cholinergic anticipation of food (Controlled by neural system)
Gastric: Presence of food and/or histamines stimulates release of gastrin which triggers gastric secretions
Intestinal: Stimulated by entrance of food into small intestine, neural/endocrine feedback
What is alkaline tide?
Peak concentration of H+ before bicarbonate is released to neutralize it
How is the timing of release of food from the stomach into the duodenum affected?
Slower time with higher fat content and larger particles
What can cause uncontrolled metabolic alkylosis?
Constant vomiting which rids the body of H+, halting the stimulation of bicarbonate release
What is chyme?
Mixture of food and acid that leaves the stomach and enters the duodenum
How does the duodenum protect itself from the acidity of chyme?
Presence of acid stimulates secretin (Hormone that travels in the bloodstream to the pancreas) which triggers pancreatic release of bicarbonate
How are pancreatic enzymes released into the duodenum?
Presence of nutrients stimulates pancreozymin (Hormone that stimulates pancreatic enzymes) which are released with bile into the duodenum and are essential for digestion
What is another name for pancreozymin?
Cholecystokinin (Suppresses appetite)
What else does pancreozymin do?
Stimulates contraction of gallbladder and bile secretion
