Chapter 30 – Digestive and Excretory Systems

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Chapter 30 Digestive and Excretory Systems
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Foods these are necessary

• Carbohydrates
• Fats
• Proteins
• Vitamins
• Minerals
• water

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Human Digestive System


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Digestion starts in the mouth

• Saliva starts mixing food
• with saliva
• - saliva comes from salivary
• glands in the cheeks and
• under the tongue.
• - saliva moistens food,
• mixes food with mucus, and
• adds enzymes that break down
• starch into sugars.

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Teeth carry out mechanical digestion

• Take care of your teeth

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Swallowed food passes into the esophagus then the
stomach

• Peristalsis is responsible for pushing food in
  one direction through the rest of the digestive
  system after the mouth.
• This occurs in the espophagus, stomach, small
  intestine, large intestine, rectum, and pushes
  wastes out of the anus.

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Digestive system problems

• Food poisoning
• Parasites such as worms
• Viral infections (hepatitis)
• Eating disorders (anorexia and bulimia)
• Diarrhea and constipation
• Flatulence! (excuse me!)

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Excretory System

• Animals produce waste products that must be
  removed from their body.
• Most animals have a system that deals with
  nitrogen-rich wastes from the breakdown of
  proteins and nucleic acids.
• Ammonia (NH3) is toxic.
• In addition, it helps maintain homeostasis
  balancing osmotic action and pH.

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Human Excretory System
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Excretory System Problems

• Kidney stones crystalized mineral salts and
  uric acid salts in the urine. Stones block flow
  of urine and cause excrutiating pain.
• Kidney failure - can be caused by long-term
  diabetes, infections, physical injuries, chemical
  poisoning. Causes toxic materials to build up to
  lethal levels.
• Dialysis or kidney transplant is the treatment.

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The End