NCM-116-FINALS

• Functions of the digestive system

  • Ingestion
  • Mechanical breakdown
  • Physical breakdown
  • Digestion
  • Secretion
  • Excretion
• Ingestion


  The active physically putting food into your mouth
• Mechanical breakdown


  Starts in the mouth with the teeth and tongue, continues in the stomach
• Physical breakdown


  Ripping, pairing, crushing food
• Digestion


  The chemical breakdown of macromolecules into smaller molecules that can be absorbed
• Secretion


  Releasing substances, fluids, enzymes into the digestive tract to assist with breakdown and movement of food
• Excretion


  Releasing waste out the exit hole
• Alimentary canal


  The digestive tract or gastrointestinal tract from mouth to anus
• Parts of the alimentary canal

  • Mouth
  • Pharynx
  • Esophagus
  • Stomach
  • Small intestine
  • Large intestine
  • Rectum
• Oral cavity (mouth)


  The starting point of chemical digestion of food
• Salivary glands


  • Parotid
  • Sublingual
  • Submandibular
• Saliva


  Mostly water, also contains enzymes, antibodies, and white blood cells
• Salivary amylase


  An enzyme that breaks down larger carbohydrates into smaller ones
• Lysozyme


  An enzyme that helps keep the bacterial population in the mouth in check
• Tongue


  A strong set of muscles that help with mechanical digestion and swallowing
• Tooth structures


  • Hard palate
  • Soft palate
  • Dentin
  • Enamel
  • Pulp layer
  • Cementum
  • Bone
  • Crown
• Tooth types


  • Incisors
  • Cuspids (canines)
  • Bicuspids
  • Molars
• Swallowing process


  • Tongue
  • Pharyngeal muscles
  • Soft palate
  • Epiglottis
  • Upper esophageal sphincter
• Esophagus


  A hollow muscular tube that moves food into the stomach through peristalsis, no absorption occurs here
• Layers of the esophagus

  • Mucosa
  • Submucosa
  • Muscular layers
  • Serosa
• Stomach


  A J-shaped organ for storage, chemical/mechanical breakdown, and emptying of chyme into the small intestine
• Regions of the stomach

  • Cardia
  • Fundus
  • Body
  • Pylorus
• Rugae


  Folds in the stomach that increase the surface area
• Major stomach cells


  • Parietal cells
  • Chief cells
• Gastrin


  A hormone that has a lot to do with the functionality of the stomach
• Ghrelin


  A hormone released by the stomach that tells the brain when you are hungry or not
• Small intestine


  Plays a key role in digestion and absorption, 18-20 feet long
• Parts of the small intestine

  • Duodenum
  • Jejunum
  • Ileum
• Intestinal villi


  Microscopic projections that increase the surface area for absorption
• Lacteal


  A projection in the villi that enables the lymphatic system to access the digested food
• Vermiform appendix


  A small, wormlike sac located near the opening into the colon
• Large intestine


  The primary function is the reabsorption of water and formation of solid feces
• Regions of the large intestine

  • Ascending colon
  • Transverse colon
  • Descending colon
  • Sigmoid colon
• Rectum


  The last 15cm of the digestive tract, for storage of feces
• Anal sphincters


  • Internal (involuntary)
  • External (voluntary)
• Hemorrhoids


  Dilation of blood vessels in the anus, caused by irritation and hard feces
• Liver


  The largest internal body organ, with many important functions including metabolism, storage, waste removal, and more
• Gallbladder


  Stores bile produced by the liver
• Pancreas


  Produces digestive enzymes and buffers
• Pancreatic enzymes


  • Alpha-amylase
  • Lipase
  • Nucleases
  • Proteolytic enzymes