DIGESTIVE

• Breaks down food into molecules the body can use

  digestive system
• Molecules are absorbed into the blood and carried throughout the body by the circulatory system
• Wastes are eliminated from the body by the excretory system
• 2 TYPES OF DIGESTION

  mechanical and chemical
• Consist of digestive tract and accessory organs

  digestive system
• Is a tube extending from the mouth to the anus

  digestive tract
• also known as alimentary tract/canal


  digestive tract
• Refers only to the stomach and intestines but often used as a synonym for digestive tract

  gastrointestinal (GI) tract
• ORAL CAVITY/MOUTH


  Tongue and teeth, salivary gland - accessory organs
• solid food/liquid are taken into the digestive tract

  ingestion
• tastants dissolved in saliva stimulate taste buds

  taste
• Mastication - chewing
• Digestion - amylase in saliva begins carbohydrate (starch) digestion
• forms food into a bolus and pushes into the pharynx

  swallowing
• Communication - lips, cheeks, teeth, and tongue are involved in speech
• Protection - lysozyme (enzyme in lyses cells) - kills microorganism
• PHARYNX/THROAT

  Tonsils as accessory organs
• DIGESTIVE TRACT CONSIST OF

  1. oral cavity/mouth
  2. pharynx/throat
  3. esophagus
  4. stomach
  5. small intestine
  6. large intestine
  7. anus
• SMALL INTESTINE


  Duodenum, jejunum, ileum, liver, gallbladder, pancreas
• LARGE INTESTINE

  Cecum, colon, rectum and anal
• Process by which the teeth chew food into the mouth. Digestive enzymes cannot easily penetrate solid food particles

  mastication
• Movement of food from one end of the digestive tract to the other

  propulsion
• Total time it takes food to travel = 24-36 hours
• Propels material through most of the digestive tract

  peristalsis
• Muscular contractions consisting of a wave of relaxation of the circular muscles in front of the bolus - wave of strong contraction of the circular muscles behind the bolus

  peristaltic wave
• Travels the esophagus in 10 seconds


  peristalsis
• Contraction that move material in the distal parts of the large intestine to the anus


  mass movement
• Some contractions do not propel food , rather move it back and forth within the digestive tract to mix it with digestive secretions to help break into smaller pieces

  Segmental contractions mixing contractions that occur in the small intestines


  mixing
• Food to digestive tract, secretions are added to lubricate, liquefy, buffer and digest the food
• Mucus secreted along the entire digestive tract
• Mechanical and chemical digestion starts here

  mouth
• Mechanical - physically breaking down food (teeth)
• Chemical - breakdown of molecules of food (saliva)
• Muscular tube connecting the mouth to the stomach

  esophagus
• Peristalsis (muscle contraction) moves the food


  esophagus
• Most chemical digestion takes place

  Some chemical with the help of digestive juices (enzymes and acids)

  stomach
• what are the digestive juices?


  enzymes and acids
• Most of the chemical digestion takes place

  Absorption of nutrients from digested food into the bloodstream

  small intestine
• Water is absorbed into the bloodstream

  Remaining material is readied for elimination from the body

  large intestine
• Waste material is compressed into solid form

  Form stool

  rectum