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Digestive System Anatomy & Physiology

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Terms in this set (31)

  • What are the main functions of the digestive system?
    Acquires nutrients from the environment, synthesizes essential compounds (anabolism), and breaks down nutrients to provide energy (catabolism).
  • What structures make up the digestive tract?
    A muscular tube extending from the oral cavity to the anus, also called the gastrointestinal (GI) tract or alimentary canal.
  • Name the accessory organs of the digestive system.
    Teeth, tongue, salivary glands, liver, gallbladder, and pancreas.
  • List the major organs of the digestive tract in order from mouth to anus.
    Oral cavity, pharynx, esophagus, stomach, small intestine, large intestine, anus.
  • What are the integrated processes of the digestive system?
    Ingestion, mechanical digestion and propulsion, chemical digestion, secretion, absorption, and defecation.
  • What is the role of the peritoneum in the digestive system?
    A serous membrane lining the peritoneal cavity; it reduces friction by producing peritoneal fluid and supports digestive organs.
  • What are mesenteries and their functions?
    Double sheets of peritoneal membrane that suspend digestive organs, provide routes for blood vessels, nerves, lymphatics, and stabilize organ positions.
  • Name the four major layers of the digestive tract wall.
    Mucosa, submucosa, muscular layer, and serosa (or adventitia where serosa is absent).
  • What is the mucosa composed of and its function?
    Epithelium moistened by glandular secretions, lamina propria of areolar tissue, and muscularis mucosae; it protects, absorbs, and secretes.
  • Describe the muscular layer of the digestive tract.
    Two layers of smooth muscle: inner circular and outer longitudinal; responsible for mechanical digestion and propulsion.
  • What is peristalsis?
    Waves of muscular contractions that move a bolus along the digestive tract by coordinated contraction and relaxation of circular and longitudinal muscles.
  • What is segmentation in the digestive tract?
    Cycles of contraction that churn and fragment the bolus, mixing contents with intestinal secretions without directional movement.
  • How is digestive activity regulated?
    By local factors (pH, stretch), neural mechanisms (short and long reflexes), and hormonal mechanisms (peptide hormones from enteroendocrine cells).
  • What are the functions of the oral cavity in digestion?
    Sensory analysis of food, mechanical digestion by teeth and tongue, lubrication by saliva, and limited chemical digestion of carbohydrates and lipids.
  • What are the types and functions of teeth?
    Incisors for cutting, canines for tearing, premolars and molars for crushing and grinding food.
  • What are the major salivary glands and their secretions?
    Parotid (serous, salivary amylase), submandibular (buffers, mucins, amylase), and sublingual (mucus).
  • Describe the stomach's main functions.
    Temporary food storage, mechanical digestion by muscular contractions, chemical digestion by acid and enzymes, producing chyme.
  • What cells are found in gastric glands and their secretions?
    Parietal cells secrete intrinsic factor and HCl; chief cells secrete pepsinogen; G cells produce gastrin; mucous cells produce mucus.
  • What are the three phases of gastric activity regulation?
    Cephalic phase (CNS stimulation), gastric phase (local neural and hormonal responses), and intestinal phase (inhibition by duodenal signals).
  • What are the major functions of the pancreas in digestion?
    Exocrine secretion of digestive enzymes and buffers into the small intestine; endocrine secretion of insulin and glucagon into the bloodstream.
  • Name the major pancreatic enzymes and their targets.
    Pancreatic alpha-amylase (starches), pancreatic lipase (lipids), nucleases (RNA/DNA), proteolytic enzymes (proteins).
  • What are the main lobes of the liver?
    Right lobe, left lobe, caudate lobe, and quadrate lobe.
  • What is the hepatic portal system?
    A venous system that carries nutrient-rich blood from the digestive tract to the liver for processing before systemic circulation.
  • What are the functions of bile produced by the liver?
    Emulsifies lipids to increase surface area for digestion, aids in lipid absorption, and facilitates waste excretion.
  • Describe the gallbladder's role in digestion.
    Stores and concentrates bile; releases bile into the duodenum when stimulated by cholecystokinin (CCK).
  • What are the three segments of the small intestine?
    Duodenum, jejunum, and ileum.
  • What structural adaptations increase the small intestine's absorptive surface?
    Circular folds, villi, and microvilli (brush border).
  • Name the major hormones secreted by the small intestine and their functions.
    Gastrin (stimulates stomach), secretin (stimulates pancreas and liver), GIP (stimulates insulin), CCK (stimulates pancreas and gallbladder), VIP (stimulates glands, dilates capillaries), enterocrinin (stimulates mucus).
  • What are the main parts of the large intestine?
    Cecum, colon (ascending, transverse, descending, sigmoid), rectum, and anus.
  • What are the functions of the large intestine?
    Absorption of water, vitamins, and nutrients; compaction of feces; storage of fecal material prior to defecation.
  • What is the defecation reflex?
    A spinal reflex triggered by rectal distension that causes peristaltic contractions and relaxation of internal anal sphincter; external sphincter is voluntarily controlled.