Gastrointestinal Physiology Flashcards
Increases H+ secretion and stimulates gastric mucosal growth?
Gastrin
Increases both exocrine and endocrine secretion of pancreas?
CCK
Increases HCO3 secretion?
Secretin
Increased insulin secretion and decreases H+ secretion?
GIP
Inhibits all GI hormones .
Somatostatin
Stimulate gastrin release?
Bombesin
Satiety center?
Ventromedial nucleus of Hypothalamus
Feeding Center?
Lateral Hypothalamic Area
Vagovagal Reflex initiated by distention of the stomach and is abolished by vagotomy?
Receptive Relaxation
The orad region of the stomach relaxes to accommodate the ingested meal.
CCk participates in receptive relaxation by increasing the distensibility of the orad stomach.
GI secretion high in HCO3 and is hypotonic?
Saliva
Saliva becomes hypotonic in the ducts because the ducts are relatively impermeable to water. Because more solute than water is reabsorbed by the ducts , the saliva becomes dilute relative to plasma.
GI secretion high in HCO3 and is isotonic?
Pancreatic secretion
Hormone responsible for increased reabsorption of Na+ and secretion of K+ in salivary ductal cells?
Aldosterone
GI secretion high in HCO3 and is isotonic ?
Pancreatic secretion
Hormone responsible for increased reabsorption of Na+ and secretion of K+ in salivary ductal cells?
Aldosterone
Autonomic innervation causing increase in saliva production?
Saliva production is unique in that it is increased by both parasympathetic and sympathetic activity .
Drug that directly inhibits H+K+ ATPase pump?
Omeprazole (PPI)
Drug that blocks H+ secretion by inhibiting cholinergic muscarinic receptors on parietal cells?
Atropine
Released from neurons in the GI tract and produces smooth muscle relaxation?
VIP
Site of intrinsic factor secretion?
Gastric fundus
Intrinsic Factor is absorbed in the ileum with B12
Mechanism of diarrhea due to vibrio cholerae?
Increase Cl- secretory channels in crypt cells.
Cholera toxin activates adenylate cyclase, increasing CAMP , activating Cl- secretory channels.
Similarity of CCK and Gastrin?
Both have 5 identical C-terminal amino acids
Because CCK heptapeptide contains 5 common amino acids, it is logical that CCK should have some gastrin-like properties.
Transport process used by amino acids?
Na+ dependent co-transport
49/M with severe Crohns disease, S/P Ileal resection, now complains of steatorrhea. Reason for steatorrhea?
Micelles do not form in the intestinal lumen, impaired fat absorption.
With Ileal resection, most of the bile acids are excreted in the feces and in the liver pool is significantly diminished. Bile acids are needed for micelles formation to stabilize the products of lipid digestion.
CCK inhibits which gastric function?
Gastric emptying
CCK helps to slow the delivery of food from the stomach to the intestine during periods of high digestive activity.
Abolishes receptive relaxation of the stomach?
Vagotomy
Receptive Relaxation (VAGOvagal Reflex) of the orad stomach is initiated when food enters the stomach from esophagus.
Secretion of this hormone is inhibited by low pH?
Gastrin
Site of gastrin secretion?
Gastric Antrum
HCl and Intrinsic Factor is secreted in the Fundus.
Which vitamin /s requires micelle formation?
Vitamin A , D, E, K (Fat Soluble)
Internal anal sphincter action during defecation
Relaxed
Tonicity of the Saliva?
Hypotonic relative to plasma
Secreted in response to an oral glucose load?
Glucose-dependent insulinotropic peptide (GIP)
Effect of CCK on pancreatic enzyme enzyme secretion?
Pancreatic enzyme secretion is increased by CCK (Cholecystokinin)
Must be further digested before it can be absorbed by specific carriers in intestinal cells?
a. Fructose
b. Sucrose
c. Dipeptides
Sucrose
Only monosaccharide can be absorbed by intestinal epithelial cells.
Disaccharides such as sucrose , must be digested to monosaccharide before they are absorbed.