Digestion

1
Digestion

• Digestive system

• Digestion is the process of breaking food down
  into molecules small enough for the body to
  absorb.

2
Types of Digestion

• Mechanical Digestion

• The physical breakdown of food by teeth in the
  mouth, and muscles in the stomach.
• Chemical Digestion
• The breakdown of fats, proteins, and complex
  carbs into smaller units by enzymes.

3
The Mouth

• Mechanical digestion begins

4
Chemical Digestion within the Mouth (cont.)

• The salivary glands produce Amylase.
• Starch is digested into its monomer glucose.

5
Esophagus

• Peristalsis

• A muscular tube that connects the mouth to the
  stomach.
• Peristalsis Involuntary waves of muscle
  contractions that push food toward the stomach.
• Mucus is a thick slippery substance produced by
  the body. It helps make food easier to swallow.

6
The Stomach

• Digestive juice contains the enzyme PEPSIN.
• Pepsin chemically digests the proteins in your
  food, breaking them down into amino acids.
• Digestive juice also contains hydrochloric acid.
  This acid helps break down food and kills many of
  the bacteria that enters your body.
• The stomach also produces mucus, which coats and
  protects the lining of your stomach.

7
The Stomach

• Most mechanical digestion takes place in the
  stomach. Three layers of muscles mixes food with
  digestive juices in a churning motion.
• As you eat your stomach will expand between 1-2
  liters to hold the food you eat.

8
The Stomach continued

• Note ( If over time to much acid continually
  builds up in the stomach a ulcer may occur.)

9
The Small Intestine

• The small intestine is about 35 - 40 feet long.
• Almost all chemical digestion and absorption of
  nutrients take place in the small intestine.
• The small intestine contains millions of tiny
  finger shaped structures called villi.

10
Digestion of Lipids (fats)
11
Absorption

• Is the process by which nutrient molecules pass
  through the wall your digestive tract and into
  the circulatory system.

12
The Liver

• The largest and heaviest organ inside the body.
• The liver produces bile, a substance that breaks
  up fat molecules.
• Bile flows from the liver to the gallbladder,
  after you eat the gallbladder passes bile into
  the small intestine.

13
The Pancreas

• The pancreas is a triangular organ that lies
  below the small intestine.
• It produces enzymes that help break down
  starches, proteins and Fats.

14
The Large Intestine

• The last section of the digestive system.
• All the remaining water is absorbed into the
  bloodstream.
• The remaining material is readied for
  elimination.
• The large intestine ends in a short tube called
  the rectum.
• The material is compressed into solid form.
• The waste material is eliminated from the body
  through the anus.