The Digestive System A Closer Look

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The Digestive System A Closer Look
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QOTD Label Me!
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Answers

1. Tongue
2. Esophagus
3. Stomach
4. Duodenum
5. Pancreas
6. ileum
7. Large Intestine
8. Rectum

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Purpose

• To enable the absorption of the nutrients needed
  for growth, maintenance and repair

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Components of Digestion

• Ingestion
• the taking in of nutrients
• enters by mouth
• Digestion
• the breakdown of complex organic molecules
  into smaller components by physical chemical
  means
• Mechanical done by teeth, and stomach
• Chemical done by the mouth, stomach,
• liver, gallbladder, pancreas, small large
  intestine.

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Break It Down Now!Enzymes

• Carbohydrases break down ________
• Peptidases break down ________
• Lipases break down ________

SEE HANDOUTS!
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Absorption

• The taking up of digested molecules into cells
• Done by stomach, small intestine (villi), large
  intestine

small intestine (villi)
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Absorption

• The Small Intestine is designed to have a large
  surface area.
• The inner membrane is folded like a fan
• The entire surface is covered with villi (villus)
• Each villus is covered with microvilli
• Absorption involves diffusion and active
  transport

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Anatomy of a Villus
Microvilli
Capillary
Proteins
Lacteal
BEFORE DIGESTION TOO BIG!!
Starches
AFTER DIGESTION SMALL ENOUGH!!
Water Minerals TO BLOOD Water soluble
vitamins (B, C) Glucose Amino Acids
Lipids
Glycerol TO LYMPH Fatty Acids Fat soluble
vitamins (A, D, E, K)
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Elimination

• The removal of waste from the body
• Done by large intestine, rectum and anus

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Control Mechanisms

• Regulation through feedback
• Done by hormones (chemical messengers)
• Thermostat Example
• -Too hot, shuts down
• -Too cold, starts furnace

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Digestion of Fats

• When fats enter the duodenum, the hormone CCK
  (Cholecystokinia) is released which causes the
  gall bladder to release bile.
• Fats are emulsified

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Acidic Chyme

• When acidic chyme enters the small intestine, the
  hormone secretin is released which causes the
  pancreas to release bicarbonate ions.
• The acid is then neutralized!

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Blood Glucose Levels

• When glucose enters the blood stream, the
  pancreas releases Insulin.
• Insulin stimulates the storage of glucose
  (as Glycogen, in the liver)
• When blood glucose levels drop too low, the
  pancreas releases Glucagon.
• Glucagon stimulates the release of glucose (from
  Liver) into the bloodstream

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Blood Sugar Levels
Check out Page 270!
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Digestive System Problems

• 1. Ulcer
• A sore wall of the stomach (peptic) or duodenum
  (duodenal)
• HCl creates a hole in the mucous liningacid
  irritates muscles
• Caused by bacteria that reduce amount of mucous.
• Treated with antibiotics

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Digestive System Problems

• 2. Cirrhosis of the Liver.
• Scar tissue in liver.
• Caused by excessive alcohol consumption and/or
  hepatitis virus.
• Results in jaundice (yellow skin), nausea, pain,
  fluid in abdomen
• Treatmentstop drinking!, vitamins, transplant.
• Read Page 273!

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Digestive System Problems

• 3. Inflammatory Bowel Disease
• Crohns Disease and Ulcerative colitis
• Inflammation of the lining of small or large
  intestine.
• Treatment Drugs, supplements or
• Resection and Colostomy
• A stoma is created, and a pouch collects the
  waste.

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Digestive System Problems

• 4. Acid Reflux
• Stomach acid burns the tissue of the esophagus
• Caused by a weak cardiac sphincter

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Digestive System Problems

• 5. Constipation
• Too much water is removed from feces
• Usually because waste is moving too slowlybunged
  up!
• Treatment Eat fibre! (cellulose), laxatives,
  suppositories.

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A CURE FOR CONSTIPATION?