Stomach physiology Flashcards
What are the 3 reflexes related to the stomach?
Gastrosalivary
Gastroileal
Gastrocolic
What is the rate of slow waves in the stomach?
4 waves/min
What is the rate of slow waves in the duodenum and jejunum?
12 waves/min
What is the rate of slow waves in the distal ileum?
8 waves/min
What is the rate of slow waves in the cecum?
9 waves/min
What is the rate of slow waves in the sigmoid colon?
6 waves/min
What are the types of motility of an empty stomach?
Migrating motor complex (MMC)
Hunger contraction
What are the types of stomach motility after a meal?
Receptive relaxation
Mixing peristaltic waves
Gastric emptying
What increases MMC?
Motilin
What abolishes MMC?
entry of meal
What are the mediators receptive relaxation of the stomach?
Vagovagal reflex
CCK increases
VIP and NO
What is the span of the normal gastric emptying time?
2-3 hours
What are the main factors that affect gastric emptying?
Fluidity of chyme
Duodenal factors
Gastric factors
What are the enterogastric hormones that inhibit gastric emptying?
CCK
Secretin
GIP
What cells produce somatostatin?
D cells
What stimulates the release of somatostatin?
Acid in stomach
What does somatostatin inhibit?
Gastric acid secretion
What stimulates the release of gastrin?
Ach
Peptides and AAs
What is the function of gastrin?
Stimulates gastric acid secretion?
What cells produce gastrin?
G cells
What cells produce gastric lipase?
Chief cells
What cells produce histamine?
ECL cells
What stimulates the release of histamine?
Ach
Gastrin
What is the function of histamine?
Stimulates gastric acid secretion
How is acid secreted by parietal cells?
Cl- is brought into the cell from the blood in exchange for bicarbonate.
Cl- diffuses into lumen
H+ is pumped into and K out of lumen by H/K ATPase
What intestinal factors inhibit HCl secretion?
Secretin
GIP
How do prostaglandins, epidermal growth factor, and transforming growth factor affect stomach secretion?
Inhibit HCl secretion
How is mucus secretion stimulated in the stomach?
Direct stimulation of mucosa by rough food
What are some things that can result in peptic ulcer disease?
H pylori infection
NSAID use
Cigarette smoking
Genetic predisposition
Blood group O
Psychological stress
What causes Zollinger-Ellison syndrome?
Gastrinoma - gastrin producing tumor in pancreas
What is seen in lab studies that indicates pernicious anemia?
Low Hgb
Macrocytes