Digestive System

1
Digestive System

• In Class Notes

2
Function (29.1)

• The digestion system breaks down foods, provides
  nutrients, and helps eliminate the waste.
• Four Steps
• 1.Ingestion eating
• 2.Digestion breaking down food
• 3.Absorption certain cells absorb small
  molecules
• 4.Elimination undigested material passes out of
  the body
• Mechanical Digestion
• Ex Chewing
• Chemical Digestion
• Ex Acids and enzymes in your stomach

3
Organs Involved (29.2)

• Mouth mechanical digestion, smashes food into
  smaller pieces for swallowing, creates greater
  surface area.
• Pharynx (upper portion of the throat) junction
  of the alimentary canal and the passageway by
  which air enters the lungs.
• Esophagus muscular tube connecting pharynx to
  the stomach. Pushes food down by contracting
  through peristalsis.
• Stomach elastic muscular sac. Gastric juices
  secreted by glands in the stomach lining.
  Contracts and uses gastric juices to kill
  bacteria and break apart the cells in food.

4
Organs involved (cont.)

• Small Intestine Long and narrow, digestion is
  completed most absorption takes place.
  Peristalsis moves chyme produced by the stomach.
  First section duodenum. Villi breaks down food
  further and kills bacteria.
• Liver Bile is produced to prepare fats for
  digestion and stored in the gallbladder.
• Pancreas produces and secretes pancreatic juice
  into small intestine. Neutralizes chyme.
• Large Intestine (colon) Very end of digestive
  process. Absorbs water and digestive juices left
  over from the process. Feces become solid due to
  water being removed moves through the large
  intestine and is removed generally taking from
  12-24 hours.

5
Sequence of digestion

• Enters mouth (mechanical digestion starts)
• Esophagus pushes food to stomach
• Stomach uses acid to breakdown food
• Food leaves the stomach as chyme to the small
  intestine
• Before long, the liver and gallbladder contribute
  bile
• Nutrients from the food are collected in the
  villi while traveling in the small intestine
• Villi have blood vessels which is cleaned in
  kidneys
• Undigested material flows through the large
  intestine
• The feces is ejected by the rectum through the
  anus

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Diagram

• Here are all the parts

7
Parts you should know
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Nutrition (29.3)
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Serving Suggestions

• Fruits- one banana,six strawberries, two plums,
  fifteen grapes, one apple, one peach, one half
  cup of orange or other fruit juice
• Vegetables- five broccoli florets, ten baby
  carrots, one roma tomato, 3/4 cup tomato juice,
  half of a baked sweet potato, one ear of corn,
  four slices of an onion
• Dairy- 1 cup of fat-free or low-fat milk, 1 cup
  of fat-free or low-fat yogurt, 1 ounce of low-fat
  cheese
• Grain- a slice of bread (35 g), ½ pita bread
  (35 g) or 125 mL (½ cup) of - cooked pasta, rice
  or couscous
• Meat- 2 to 3 ounces of cooked lean meat, poultry
  or fish

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Vocabulary

• Bolus- A clump of food that leaves mouth to
  stomach
• Peristalsis- Muscle contractions that move food
• Constipation- When you cant poop
• Diarrhea- When you cant stop pooping
• Nutrition- Healthy amount of food
• Ingestion- Eating
• Absorption- absorbing vitamins from food
• Elimination- pooping out your food
• Feces- poop in the large intestine
• Chyme- Stomach acid and food
• Saliva- liquid in mouth to break up food

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Nutritional Disorders (29.4)

• Malnutrition A diet lacking one or more
  essential nutrients
• Under nutrition Lack nutrients and calories in
  a diet.
• Obesity The condition of being seriously
  overweight can increase risk of heart disease,
  diabetes, stroke, and asthma. About 60 of
  Americans suffer from Obesity. About 13 are
  children/teens.
• Eating Disorders mental condition that affects a
  persons diet. Ex Are Anorexia and Bulimia.

12
Digestive System Disorders

• A. Gluten Allergy- Celiac Disease Scars lining
  of the small intestine.
• B. Anorexia- Eating disorder. Self-starvation.
• C. Ulcers- Open painful wound in the stomach. D
• D. Constipation- Colon absorbs too much water,
  poor diet can be another factor.
• E. Cronns Disease- Genetic. Inflamed GI track.
• F. Heartburn- Stomach acid gets into the
  esophagus. Also called acid reflux.
• G. IBS- Irritable Bowel Syndrome Genetic.
• .Thats all
  Folks.