Digestive System Flashcards

Flashcards covering key vocabulary and concepts from the Digestive System lecture.

Rugae

Folds in the mucosa of the stomach that allow for stretching.

Stomach Functions

Store food, regulate delivery to the small intestine, finish mechanical digestion, start chemical digestion of proteins, minimal chemical digestion of fats.

Gastric Glands

Located in the lamina propria of the stomach, connecting to narrow channels called gastric pits; secrete mucus and gastric juice (HCl, pepsinogen, gastric lipase, intrinsic factor).

Hydrochloric Acid (HCl)

Kills microbes, partially denatures proteins, and converts pepsinogen into pepsin in the stomach.

Pepsin

Enzyme that digests proteins in the stomach.

Gastric Lipase

Enzyme that digests triglycerides in the stomach.

Intrinsic Factor (IF)

Substance needed for absorption of vitamin B12 in the terminal ileum.

Chyme

The product of food and gastric juice reduced by mixing waves in the stomach.

Pyloric Sphincter

Regulates the passage of chyme from the stomach into the duodenum.

Small Intestine Function

Finishes chemical digestion of food and absorbs the vast majority of food.

Duodenum

Regulates food supply into the small intestine and receives chyme and secretions from the pancreas and liver/gallbladder.

Pancreas Function (exocrine)

Secretes enzymes for chemical digestion and sodium bicarbonate to buffer acidic chyme.

Bile

Produced by the liver, stored in the gallbladder, and secreted into the duodenum; emulsifies and aids in absorption of lipids.

Common Bile Duct (CBD)

Formed by the joining of the cystic duct from the gallbladder and the common hepatic duct from the liver.

Hepatopancreatic Ampulla

Where the common bile duct joins the pancreatic duct to deliver contents into the duodenum.

Cholecystokinin (CCK)

Hormone that causes the gallbladder to release stored bile.

Small Intestine Regions

Duodenum, jejunum, and ileum.

Plicae Circulares

Circular folds in the small intestine that increase surface area for absorption.

Villi

Finger-like projections in the small intestine that are covered with simple columnar epithelium and aid in absorption.

Microvilli

Microscopic folds on the apical surface of the plasma membrane of simple columnar cells in the small intestine.

Chylomicrons

Aggregated globules of lipids coated with proteins that enter lacteals (lymphatic system) in the small intestine.

Brush Border Enzymes

Enzymes on the villi of the small intestine that finish chemical digestion.

Segmentation (in small intestine)

Minimal mechanical digestion that mixes chyme with digestive juices.

Liver Lobules

Repeating functional units of the liver.

Hepatocytes

Major functional cells of the liver; perform digestive functions, detoxification, and bile production.

Liver Non-Digestive Functions

Phagocytosis of old cells, making heparin and plasma proteins, modifying vitamin D.

Hepatic Portal Vein

Carries venous blood from the small intestine to the liver.

Kupffer Cells

Liver macrophages that destroy red cells, white cells, and bacteria.

Large Intestine Functions

Absorb water, some minerals and vitamins, and eliminate waste.

Large Intestine Parts

Cecum, colon (ascending, transverse, descending, sigmoid), rectum, and anal canal.

Teniae Coli

Longitudinal ribbons of smooth muscle that run the length of the colon.

Haustra

Small pouches segmented by the teniae coli in the colon.

Cecum

Small pouch inferior to the ileocecal valve in the large intestine.

Appendix

Coiled tube attached to the cecum.

Anal Canal

Last 1 inch of the rectum, opening to the exterior through the anus.

Large Intestine Fluid Absorption

Absorbs remaining fluid after small intestine absorption, excreting only ~100 mL/day in feces.

Gastroileal and Gastrocolic Reflexes

Autonomic nervous system reflexes initiated by distension of the stomach that promote movement of food through the intestines.