Digestive System

1
Digestive System

• Normal Digestion

2
Structures

• X. Salivary gland
• C. Esophagus
• D. Stomach
• Y. Gall bladder
• A. Liver
• E. Pancreas
• F. Small intestine
• B. Large intestine

3
Function

• Mouth- Saliva from the salivary gland begins to
  break down starches in the process of chemical
  digestion teeth begin mechanical digestion by
  grinding the food into smaller particles.

4
Function

• Esophagus- the epiglottis seals off the pharynx
  (windpipe) and directs food into the esophagus.
  The mucus lining of the esophagus helps food
  slide down into the stomach. Rhythmic
  involuntary muscle contractions called
  peristalsis keeps food moving through the system.

5
Function

• Stomach- most mechanical digestions occurs here
  as the stomach churns food into smaller particles
  for chemical digestion by substances produced by
  the stomach. Pepsin breaks down proteins.
  Hydrochloric acid kills bacteria and provides an
  acid environment for pepsin. Mucus protects the
  stomach from the strong acid.

6
Function

• Gall bladder- stores bile produced by the liver.
  Bile is an enzyme that breaks down fats.
• Pancreas- this gland releases amylase for starch
  digestion, trypsin to continue protein breakdown,
  and lipase for fat digestion. The pancreas also
  releases insulin that is vital for maintaining
  healthy blood sugar levels.

7
Function

• Small Intestine- absorption of nutrients and
  water takes place across the tiny folds of the
  lining of the small intestine that are called
  villi. The enzyme peptidase breaks down proteins
  and the enzyme maltase converts remaining sugars
  into glucose.

8
Function

• Large intestine- this is the final stage of
  digestion. Bacteria in the large intestine aid
  the final processing of any nutrients remaining
  in the digested material. Vitamin K, a blood
  clotting factor, is produced by bacteria in the
  large intestine. Excess water and other waste is
  returned to the intestine to be readied for
  elimination through the rectum and anus.

9
Vocabulary

• Absorption- the process by which nutrient
  molecules pass through the wall of the digestive
  system into the blood.
• Calorie- the amount of energy needed to raise the
  temperature of one gram of water one degree
  Celsius.
• Digestion- the process by which the body breaks
  down food into small nutrient molecules.

10
Vocabulary

• Enzyme- a protein that speeds up chemical
  reactions in the body.
• Mucus- a thick, slippery substance produced by
  the body.
• Peristalsis- involuntary waves of muscle
  contraction that keeps food moving along in one
  direction through the digestive system.

11
Skin

• Epidermis- outer layer of skin (4)
• Dermis- skin layer where the sweat glands (1),
  hair follicle (3), and oil glands (2) are located

4
2
3
1
12
Balance

• What is homeostasis?
• What are the effects of adrenaline?

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