Digestive And Excretory Systems

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DigestiveAnd ExcretorySystems
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Digestive System
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Functions of the Digestive System

• Digestion
• Waste Removal (solid)
• Conversion of food energy to energy usable by the
  body
• Absorption of nutrients.

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Organs of the Digestive System

• Mouth
• Salivary glands
• Esophagus
• Stomach
• Small Intestine
• Large Intestine
• Liver
• Pancreas

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Digestive Process
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In the mouth

• Food is chewed and swallowed
• Enzymes are added to food in this process.
• Once swallowed, it moves down the esophagus to
  the stomach

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Enzymes

• Proteins that catalyze, or increase the rates of
  chemical reactions.

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Peristalsis

• Process where food is moved through the digestive
  system by waves of rhythmic muscular contractions.

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In the stomach

• Strong acid and powerful enzymes mix with the
  food and break down the food into chyme.
• It is then moved to the small intestine.

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In the Small Intestine

• Secretions from the small intestine, liver, and
  pancreas finish breaking down the proteins,
  carbohydrates, and fats
• Most of the absorption of nutrients takes place
  in the small intestine

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In the Large Intestine

• Vitamins, Minerals, and Water are absorbed.

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Role of the Liver in digestion

• Secretes chemicals that help digest fats in the
  small intestine.
• Stores energy reserves.

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Role of the Pancreas in digestion

• Secretes enzymes that break down carbohydrates
  and proteins in the small intestine.

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Excretory System
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Functions of the Excretory System

• Removes waste made by cells
• Maintains
• salt content
• water content
• blood pressure
• acid-base balance

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Organs of the Excretory System

• Kidneys
• Lungs
• Skin

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Kidneys

• Filter blood about 10 times a day. (about 1 liter
  per hour)

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Nephrons

• Blood filtering units in the kidney.
• Each kidney has millions of them.
• They remove salts, water, and cell waste from the
  blood.
• 99 of the water removed by the nephrons is
  reclaimed by the capillaries.
• Liquid waste is called urine.

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Urinary Tract

• Ureter tube that carries urine from the
  kidney to the urinary bladder.
• Urinary Bladder stores urine.
• Urethra tube that runs from the urinary
  bladder to the outside of the body.

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Lungs

• Remove carbon dioxide (CO2) from the blood and
  expels it from the body

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Skin

• Excretes water, salts, small amounts of hydrogen
  wastes, and other substances such as toxins in
  sweat