Digestive System

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Digestive System
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Human Digestion

• Alimentary Canal
• Mouth
• Pharynx
• Esophagus
• Stomach
• Small Intestine
• Large Intestine
• Accessory Glands and Organs
• Salivary Glands
• Pancreas
• Liver
• Gallbladder

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Where it all begins

• In the mouth
• One Liter of saliva is produced each day by three
  main salivary glands (8).
• Salivary enzyme
• Amylasebreaks down starch into smaller
  polysaccharides and the disaccharide maltose.
• What type of reaction is this?

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Mechanical Digestion

• Before food can move safely down the alimentary
  canal it needs to be broken down into smaller
  pieces
• Teeth (1)purpose is to rip, grind, and generally
  pulverize all the food we put into our mouths.
  Why?
• Tongue (9)strong muscle used to move food around
  the mouth, taste, and move food towards the back
  of the mouth.

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Taste Buds
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Epiglottis Esophagus

• Epiglottis (2)trap door. Swallowing triggers
  its closing over the trachea to prevent food and
  fluids from draining into lungs.

• Esophagus (10)Moves food bolus from the mouth
  to the stomach via peristalsis (involuntary
  muscle contractions squeeze and release)

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Esophagus Disorders

• Reflux Esophagitis or Heartburn

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Stomach (11)

• Food undergoes further chemical and mechanical
  digestion in the stomach.
• Gastric juice is secreted
• Mucus
• Hydrochloric Acid
• Breaks apart cells and kills many of the bacteria
  swallowed with food.
• Enzymes
• Pepsinbreaks down proteins into smaller
  polypeptides

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Stomach Disorders

• Gastritisinflammation of the stomach
• Peptic Ulcer Disease, Gastric Ulcer, Stomach
  Ulcer
• Gastric Cancer, Stomach Cancer

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Pyloric Sphincter

• Regulates the flow of chyme from the stomach to
  the small intestine.
• The stomach usually empties about 2-6 hours after
  a meal is swallowed.

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Duodenum (12)

• Chyme arrives in the duodenum and signals the
  stomach to slow down.
• Vital secretions from the pancreas, liver, and
  gallbladder for the digestion of fat.

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Liver (3)

• The main job is to store, package and change
  nutrients absorbed from the small intestine
  according to the needs of the body and then
  supply them to the blood stream for delivery to
  the various organs.

• It also produces bile which is stored in the
  gallbladder.
• Bile is necessary for the digestion and
  absorption of fat in the diet.

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Gallbladder (4)

• Located behind the liver.
• Bile is released from the gallbladder when fat
  arrives in the duodenum and travels through the
  common bile duct (5)
• Bile separates small fat droplets which prevents
  them from clumping. This allows digestive
  enzymes to break down the fat more easily.

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Gallbladder Disorders

• Gallstones
• An imbalance of cholesterol in the gallbladder

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Pancreas (13)

• An organ located immediately next to the
  duodenum. 
• Secretes digestive enzymes into the small
  intestine in order to help digest carbohydrates,
  protein and fat.
• Controls blood sugar by releasing insulin when
  levels are too high and glucagon when levels are
  too low.
• Also secretes bicarbonate and water which
  neutralize the acid mixed with the food delivered
  into the duodenum from the stomach.

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Small Intestine (14)

• 20-22 feet in length and 2.5 cm in width.
• Villi increase the surface area to about the size
  of a tennis court.
• Chemical digestion is completed in the small
  intestine.

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Small Intestine Cont

• Duodenum
• continues the breakdown of food into liquid form
• Jejunum ileum
• absorption of nutrients
• fatty acids glycerol are absorbed by the
  epithelial cells
• amino acids carbohydrates are absorbed into the
  blood stream through the capillaries in each
  villi.

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Small Intestine Disorders

• Duodenal Ulcer, Peptic Ulcer Disease
• Imbalance in stomach acid to small intestine
• Lactose Intolerance
• Celiac Disease, Gluten Enteropathy
• Inability to tolerate gluten which leads to
  damage of intestine and difficulty absorbing
  nutrients.

• Crohn's Disease
• Ulcers can become severe and cause fistulas (a
  continuation of the ulcer into other organs)
• Travelers Diarrhea, Tijuana Trots
• E.coli

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Appendix (7)

• Accessory structure that extends from the first
  section of the large bowel.
• Was possibly larger in early humans and assisted
  in fiber digestion?
• Thought to be a storage space for intestinal
  bacteria.
• Whats so bad about an appendicitis?

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Large Intestine (6)

• Is it poop yet? Waste products leave through the
  rectum (15).
• The main purpose of the large intestine is
• To pass remaining essential nutrients into the
  bloodstream
• Store and elimination of waste
• Re-absorption of water.

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Colon Disorders

• Constipation, Diarrhea, Irritable Bowel Syndrome,
  Spastic Colon
• Colon Cancer
• Ulcerative Colitis, Inflammatory Bowel Disease
• Gas
• Hemorrhoids