BackAnatomy & Physiology: Digestive System Key Concepts
4:06
Terms in this set (31)
Receptive relaxation occurs in the fundus and body of the stomach, involving anticipation and response to food, controlled by the vagus nerve.
Adaptive relaxation refers to the stomach's ability to dilate to accommodate incoming food without increasing pressure.
Stress relaxation is the stretching of stomach smooth muscle without increasing tension, allowing the stomach to expand.
Pacesetter cells generate rhythmic waves of depolarization and repolarization, setting the rate of smooth muscle contractions but not initiating them.
Rate depends on stomach processes and duodenal contents; larger meals and more liquid increase emptying speed.
Receives blood from superior mesenteric artery, parasympathetic innervation from vagus nerve, and sympathetic innervation from long splanchnic nerves.
Transports nutrient-rich blood from the small intestine to the liver for processing.
Shortest small intestine segment (~25 cm), receives chyme, bile, and pancreatic enzymes; has few circular folds and small villi.
Site where the pancreatic duct and bile duct join and empty their contents into the duodenum.
Middle small intestine segment (~2.5 m) with prominent circular folds and villi; primary site of nutrient absorption.
Last small intestine segment (~1.5 m), absorbs vitamins and remaining nutrients; circular folds and villi decrease distally; terminal ileum lacks folds.
Permanent circular folds in the small intestine that increase surface area for absorption, especially in the proximal part.
Villi increase surface area and are made of enterocytes; microvilli are on enterocyte surfaces, further increasing absorption area.
Complete final digestion of carbohydrates and proteins; activate trypsinogen into trypsin.
Transports materials like protein-lipid packages that cannot enter capillaries, aiding fat absorption.
Secrete mucus with bicarbonate to neutralize chyme pH and release enterocrinin; located in submucosa and stimulated parasympathetically.
Hormone secreted to neutralize acidic chyme entering the duodenum.
Released in response to fat or protein; stimulates gallbladder to release bile for fat digestion.
Enzyme that breaks down starch into simpler sugars.
Secreted as inactive proenzymes; include protease (break large proteins) and peptidase (break peptides into amino acids).
Activates other pancreatic proenzymes like chymotrypsinogen, procarboxypeptidase, and proelastase into active forms.
Liver has four lobes (left, right, caudate, quadrate); hepatocytes detoxify, produce bile, and process nutrients.
Bile produced by hepatocytes flows into bile canaliculi, then bile ductules, bile ducts, and finally the common bile duct.
Metabolic regulation (nutrient storage/removal), hematological regulation (bile production), and bile secretion.
Process where bile salts break down lipids into smaller droplets to increase surface area for enzyme action.
Release of CCK by the duodenum stimulates the gallbladder to release bile for fat digestion.
Stores waste, absorbs water, and synthesizes vitamins K, B, and biotin.
Contains teniae coli (smooth muscle bands), haustra (pouches for expansion), and omental appendices (fat sacs).
Internal anal sphincter is involuntary smooth muscle; external anal sphincter is voluntary skeletal muscle.
Approximately 75% water, 5% bacteria, and 20% indigestible material.
Decline in epithelial stem cell division, decreased smooth muscle tone causing constipation, loss of teeth, and increased cancer risk.