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Nat. Review chpt. 14
Digestive system
Question | Answer |
---|---|
Digestive tract | Gastrointestinal tract |
Gastrointestinal tract | Continuous pathway that food follows from the mouth to the anus |
Accessory organs | Organs that secrete substances that travel through ducts into the digestive tract to help with digestion, not a part of the digestive tract |
Serosa | External epithelial membrane that surrounds the organs and walls in the peritoneal cavity |
Visceral peritoneum | Layer of peritoneum investing the abdominal organs |
Parietal peritoneum | Lines abdominal cavity |
Peritoneal cavity | Abdominal cavity |
Mesentary | Supportive structure composed of two layers of serosa, connects to the intestines, contains the blood vessels, lymph vessels, and nerves that run to and from the intestinal wall |
Muscularis | Two layers of smooth muscle, mixes food with digestive juices and moves food through the digestive tract |
Peristalsis | Wave-like movement of food through the digestive track |
Submucosa | Layer of connective tissue beneath the mucosa that contains blood bessels, nerves, and lymph vessels |
Mucosa | Internal mucous membrane through which the body absorbs digested substances into the blood |
Villi | Small, finger-like projections on the mucosa where absorption of nutrients and fats takes place, contain blood vessels and lacteals |
Lacteals | Specialized lymph vessels |
Oral cavity | Mouth |
Mouth | Begining of the digestive tract, aids in speech, ingests food, and prepares food for digestion by breaking it up into smaller pieces |
Ingest | Take in |
Salivary glands | Three pairs of accessory organs to the digestive system, produce saliva |
Saliva | Fluid that helps break down starches into sugars |
Parotid glands | Largest pair of salivary glands, located anterior and inferior to the ear |
Submandibular glands | Salivary glands located under the mandible |
Sublingual glands | Salivary glands located under the tongue |
Pharynx | Throat |
Throat | Divided into the oropharynx and the larynogpharynx, a passageway for food, also used for respiration |
Soft palate | Soft tissue on the back of the roof of the mouth, contains the uvula |
Uvula | Small, soft, v shaped structure hanging from the bottom of the soft palate in the midline above the back of the tongue |
Esophagus | Muscular tube that carries food from the pharynx to the stomach |
Cardiac sphincter | Circular or ring-shaped muscle at the base of the esophagus, prevents food and gastric juice from going back up into the esophagus |
Stomach | J-shaped organ positioned in the left upper abdomen |
Fundus of the stomach | Bulge at the top of the stomach |
Rugae | Folds in the stomach lining |
Pylorus | Lowest portion of the stomach, contains the pyloric sphincter |
Pyloric sphincter | Muscle that controls passage of food from the stomach into the small intestine |
Gastric juice | Acid fluid (pH abt. 2.1) produced by the stomach, contains hydrochloric acid and pepsin |
Hydrochloric acid | Aqueous solution of hydrogen chloride; a strongly corrosive acid |
Pepsin | Enzyme in the stomach that begins the digestion of proteins by splitting them into smaller pieces |
Small intestine | Small-diameter tube connecting stomach to large intestine, longest part of the digestive tract, where digestion process is completed, followed by absorption of most nutrients |
Duodenum | First 25 cm of the small intestine, receives bile and pancreatic juice through ducts from the liver, gallbladder, and pancreas |
Bile | Digestive juice secreted by the liver and stored in the gallbladder; aids in the digestion of fats |
Pancreatic juice | Fluid secreted into the duodenum by the pancreas; important for breaking down starches and proteins and fats |
Muriatic acid | Hydrochloric acid |
Bolus | Small portion of chewed food together with saliva |
Heartburn | When food and gastric juice slips through the cardiac sphincter and reenters the esophagus |
Chyme | Food and gastric juice once it has entered the small intestine |
Feces | Food that has passed into the large intestine |
Vermiform appendix | Wormlike “pouch” several inches long located near the top of the large intestine, in the lower right portion of the abdomen. At this time, the role the appendix plays in the human body is not known although it does contain lymphatic tissue which would all |
Jejunum | Middle segment of the small intestine |
Ileum | Last part of the small intestine, connects to the cecum of the large intestine via the ileocecal valve |
Ileocecal valve | Valve between the ileum of the small intestine and the cecum of the large intestine; prevents material from flowing back from the large to the small intestine |
Large intestine | Large tube that connects the small intestine to the anus, absorbs water and electrolytes from the feces |
Cecum | Large pouch that forms the first segment of the large intestine |
Ascending colon | Ascends from the cecum along the right side of the abdomen |
Transverse colon | Crosses the abdominal cavity from right to left just below the diaphragm |
Descending colon | Descends from the transverse colon down the abdomen on the left side |
Sigmoid colon | S-shaped section of colon before the rectum |
Rectum | Last 20 cm of digestive tract |
Anus | Last 2-3 cm of the rectum, provides the external opening, contains two sphincter muscles that control defecation |
Defecation | Process of expelling feces |
Internal anal sphincter | Ring of smooth muscle |
External anal sphincter | Ring of skeletal muscle |
Liver | Largest internal organ, made up of four lobes, highly vascular, positioned directly beneath the diaphragm in the upper right quadrant of the abdomen |
Liver functions | Storage of glycogen, synthesis of blood proteins, destruction of old red blood cells, manufacture of bile to break down fats, removal of toxic substances, storage of vitamins and minerals, sythesis of urea |
Urea | Waste product from protein metabolism |
Gallbladder | Muscular sac under the liver, functions as a storage pouch for bile |
Pancreas | Soft organ positioned below the stomach and behind the peritoneum, produces and alkaline fluid called pancreatic juice that breaks down fats, proteins, carbohydrates, and nucleic acids |
Bile ducts | Tubes that carry bile from the liver and gallbladder to the duodenum |
Hepatic duct | Carries bile from the liver, joins with the cystic duct |
Cystic duct | Carries bile from the gallbladder, joins with the hepatic duct |
Common bile duct | Takes bile from the cystic duct and hepatic duct into the duodenum |