High-Yield Physiology Concepts Flashcards
Gastrin
Secreted by G cells (antrum), stimulates parietal cells in fundus
Cholecystokinin (CCK)
Secreted by I cells (duodenum), contracts gallbladder & prolongs gastric emptying time
Secretin
Secreted by S cells (duodenum), inhibits acid secretion
Glucose-dependent Insulinotropic Peptide (GIP)
Secreted by K cells (duodenum), stimulates insulin secretion
Gastrin, Histamine, Acetylcholine
Stimulate gastric acid secretion (synergistic effects)
Motilin
Stimulates motility during fasting
Mucus Neck Cells
Secretes mucus in the stomach
Parietal Cells
Secretes HCI and Intrinsic Factor (IF) in the stomach (HCL = parietaL)
Chief Cells
Secretes pepsinogen in the stomach
Enterochromaffin Cells
Secretes serotonin in the stomach
Enterochromaffin-Like Cells
Secretes histamine in the stomach
Interstitial cells of Cajal
Pacemaker cells of the GI tract (generate slow waves)
Liver Acinus Model (Zones 1-3)
Preferred functional unit of the liver
Ito Cells
Store vitamin A in the liver
Enterokinase
Intestinal enzyme that triggers conversion of pancreatic trypsinogen to trypsin
Main Mechanism for Bile Salt Reabsorption
Enterohepatic circulation
Triglyceride Absorption
Lumen → Intestinal Cells as Micelles
Intestinal Cells → Lymph Vessels (Lacteals) as Chylomicrons
Start of Digestion: Carbohydrates
Mouth (salivary amylase/ptyalin)
Start of Digestion: Fats
Stomach (lingual lipase)
Start of Digestion: Proteins
Stomach (pepsin and denaturation by HCI)
Absorption of Nutrients: Duodenum
Iron, vitamin C
Absorption of Nutrients: Jejunum
Carbohydrates, fats, proteins, water
Absorption of Nutrients: Ileum
Vitamins B12, IF, bile salts, vitamins ADEK
