L4 | DIGESTIVE SYSTEM

• 5 PHASES OF DIGESTION

  1. Ingestion
  2. Digestion
  3. Absorption
  4. Assimilation
  5. Egestion / Defecation
• TYPES OF DIGESTION

  1. Mechanical (physical)
  2. Chemical
• MECHANICAL DIGESTION

  • Chew, tear, grind, mash, mix
• CHEMICAL DIGESTION

  • Enzymatic reactions to improve digestion of:
  • Carbohydrates
  • Proteins
  • Lipids
• DIGESTIVE SYSTEM

  1. Mouth
  2. Esophagus
  3. Stomach
  4. Small Intestine
  5. Large Intestine

  ACCESSORY ORGANS

  1. Liver
  2. Gall Bladder
  3. Pancreas
• MOUTH

  • Where digestion begins
• TEETH

  • Mechanically break down food into small pieces.
• TONGUE

  • Mixes food with saliva (contains amylase)
  • Which helps break down starch.
• EPIGLOTTIS

  • Flap like structure at the back of the throat
  • Closes over the trachea preventing food from entering it
• ESOPHAGUS

  • Approx. 10" long
  • Food passageway b/w mouth and stomach
  • Functions:
  • Secret mucus
  • Moves food from throat -> stomach: Peristalsis
• STOMACH

  • J-shaped muscular bag that stores the food, and breaks it into tiny pieces.
  • Mixes food with digestive juices that contain enzymes to break down proteins and lipids.
  • Acid in the stomach kills bacteria.
  • Food found is called chyme.
• PERISTALSIS

  • Series of involuntary muscle contractions that move food and urine through the body
• SMALL INTESTINE

  • Roughly 7 meters long
  • Absorbs useable food substances that are sent to all body parts by blood vessels
  • Food digestion is now complete
• VILLI

  • Lining of intestine walls has fingerlike projections
  • To increase surface area
  • Covered in microvilli which further increase surface area for absorption
• BILE

  • Aids in the chemical digestion of lipids
• SMALL INTESTINE

  • Absorbs:
  • 80% ingested water
  • Vitamins
  • Minerals
  • Carbohydrates
  • Proteins
  • Lipids
• LARGE INTESTINE

  • About 5 feet long
  • Continues to absorb water
  • Concentrates waste
  • Stores unused solid substances after water is removed
• RECTUM

  • Short term storage which holds feces before it is expelled
• ACCESSORY ORGANS

  • Not part of the path of food, but play a critical role
• LIVER

  • Directly affects digestion by producing bile
  • Helps digest fat
  • Filters out toxin and waste
• GALL BLADDER

  • Stores bile from the liver, releases it into the small intestine
  • Fatty diets can cause gallstones
• PANCREAS

  • Produces digestive enzymes to digest fats, carbohydrates, and proteins
  • Regulates blood sugar by producing insulin
• BOLUS

  • Partially digested food in your mouth
• DIGESTION

  • Where most chemical digestion happens due to different gastric juices
  • HCL ACID
  • Hydrochloric acid
  • Secreted into the stomach
  • BILE
  • Gallbladder
  • Burning out fatty good
  • PANCREATIC JUICES
  • Pancreas
• ABSORPTION

  • Small intestine will get all the nutrients from the chyme
• ASSIMILATION

  • Large intestine gets the other nutrients of chyme
  • The unwanted nutrients will become a solid waste and stored in the rectum
• EGESTION / DEFECATION

  • Released by the anus / anal opening
• DIGESTIVE SYSTEM

  A) Esophagus

  B) Liver

  C) Stomach

  D) Pancreas

  E) Small Intestine

  F) Large Intestine

  G) Gall Bladder