7 - Digestive System Flashcards
Breaking down of food into smaller particles and of macromolecules in food into smaller, absorbable molecules.
Digestion
Release of digestive enzymes and bile into the lumen of the GI tract.
Secretion
Movement of the molecules resulting from digestion from the GI tract lumen across a layer of epithelial cells and into the blood or lymph.
Absorption
Contractions of the smooth and some skeletal muscles in the GI tract wall that mix the luminal contents and propel them from mouth to anus.
Motility
Enzyme, found in saliva, begins polysaccharide digestion.
Amylase
Exocrine secretion of the stomach, kills bacteria, dissolves the particulate matter in food, activates pepsinogen into pepsins.
Hydrochloric acid
Exocrine secretion of the stomach, begins the digestion of proteins.
Pepsin
Exocrine secretion of the stomach, lubricates and protects the stomach.
Mucus
Exocrine secretion of the stomach, used for vitamin B12 absorption in the small intestine.
Extrinsic factor
Solution of partially digested protein/polysaccharide fragments/fat droplets/salt/water in the stomach/SI/LI.
Chyme
Performs most digestion
Small intestine
Secreted from exocrine portion of pancreas.
Pancreatic juice (i.e. contains bicarbonate and enzymes for digestion)
Secretion of the liver involved in digestion
Bile salts and bicarbonate
Gallbladder stores and concentrates bile between meals and contracts to secret it into the […] when needed
Duodenum
Connective tissue layer just beneath the mucose that contains a network of neurons plus blood and lymphatic vessels.
Submucosa
Network of neurons within the submucosa.
Submucosal plexus
Network of neurons between the two layers of the muscularis externa.
Myenteric plexus
Fibers of the muscularis externa, encircle the tuble and therefore narrow its lumen when they contract.
Circular muscle
Fibers of the muscularis externa, run along the tube and thus shorten the tube when they contract
Longitudinal muscle
Thin layer of connective tissue forming outer surface of the GI tube.
Serosa
Outer tunic in the esophagus.
Adventita
Projections of the SI, extend from the luminal surface.
Villi
Blind-ended lymphatic vessel found within the center of each villus.
Lacteal (i.e. also house a blood capillary)
Veins draining the SI merge to form the […]
Hepatic portal vein (i..e travels to a second network within the liver)
Serous membrane, similar to pleural and pericardial membranes, covers the external surfaces of many digestive organs, lines the inner surface of the abdominpelvic cavity wall.
Peritoneum
Extends from the body wall to some digestive organs, holds organs in place and provides routes for blood vessels, lymphatics, and nerves to reach organs.
Mesentery
Most lipids are ingested as […]
Triglycerides
Enzyme, does most of digesting of lipids in the SI.
Lipase
Process by which droplets of fat are made into smaller droplets to speed up digestion.
Emulsification
Phospholipid found in bile that acts as an emulsifying agent
Lecithin
