Gastric System Physiology

In a study of the secretion of gastrointestinal hormones, portal concentrations are measured in a rat during luminal perfusion of buffered salt solutions at various pH levels.  Which of the following hormones will increase during perfusion with a buffered solution at pH 3.0?

• Cholecystokinin

• Gastrin

• Glucose-dependent insulinotropic peptide

• Motilin

• Secretin

Cholecystokinin (CCK) has some gastrin-like properties because both CCK and gastrin  

• Released from G cells in the stomach

• Released from I cells in the duodenum

• Members of the secretin-homologous family

• Have five identical C-terminal amino acids

• Have 90% homology of their amino acids

A patient suffering from anemia comes to his physician complaining of frequent bouts of gastroenteritis. A blood test reveals the presence of antibodies directed against gastric parietal cells. The anemia in this patient is attributable to the hyposecretion of which gastric product?

• Histamine

• Gastrin

• Pepsinogen

• Intrinsic factor

• Hydrochloric acid

Two medical students studying for their physiology exam decided to take a break for a lunchtime hamburger. Before reaching the cafeteria, nervous impulses from the dorsal vagal complex will initiate gastric acid secretion by triggering release of which neurotransmitter from the enteric nervous system?

• Norepinephrine

• Vasoactive intestinal polypeptide

• Substance P

• Gastrin-releasing peptide

• Nitric oxide

A 3-year-old boy is brought to his pediatrician for an evaluation because of failure to thrive and frequent diarrhea characterized by pale, bulky, foul-smelling stools. Sweat chloride concentrations are measured and found to be elevated. Diminished secretion of which pancreatic product is most likely to be the primary cause of the patient’s apparent fat malabsorption?

• Lipase

• Procolipase

• Monitor peptide

• Cholecystokinin

• Bicarbonate

A researcher conducts a study of the regulation of salivary secretion in a group of normal volunteers under various conditions. Which of the following conditions would be expected to be associated with the lowest rates of secretion?

• Chewing gum

• Undergoing a mock dental exam

• Sleep

• Exposure to a nauseating odor

• Resting control conditions

A 50-year-old female patient who has suffered for several years from severe dryness of her eyes due to inadequate tear production is referred to a gastroenterologist for evaluation of chronic heartburn. Endoscopic evaluation reveals erosions and scarring of the distal esophagus. Reduced production of which salivary product most likely contributed to this tissue injury?

• Bicarbonate

• Lactoferrin

• IgA

• Mucus

• Amylase

A newborn baby is brought to the pediatrician suffering from severe diarrhea that worsens after feeding. The symptoms diminish when nutrients are delivered intravenously. The child most likely has a mutation in which of the following intestinal transporters?

• Na+, K+ ATPase

• NHE3

• SGLT-1

• H+, K+ ATPase

• NKCC1

An infant who was previously healthy but is displaying symptoms of acute diarrhea and dehydration after an infection is given an oral solution of glucose and electrolytes (Pedialyte). What membrane protein accounts for the ability of this solution to provide rapid hydration?

• Sucrase-isomaltase

• SGLT-1

• CFTR

• Chloride-bicarbonate exchanger

• Lactose-phlorizin hydrolase

A 6 year old child was brought to her pediatrician exhibiting signs of malnutrition, diarrhea, and edema of the extremities. Duodenal aspirates were obtained at endoscopy after intravenous administration of cholecystokinin, and was found to be incapable of protein hydrolysis at neutral pH unless a trace amount of trypsin is added that by itself would not result in appreciable hydrolysis. The patient was most likely suffering from a deficiency in which of the following?

• Pepsinogen

• PepT1

• Trypsinogen

• Carboxypeptidases

• Enterokinase