1. Digestive & Excretory System Notes

2. The Digestive System
Digestion is the process by which the body breaks down food into smaller nutrient molecules.
Breaks down food into molecules
Molecules are absorbed into blood and carried through the body
Wastes are eliminated

3. The Digestive System Upper Digestive System Mouth
Chemical digestion - saliva
Mechanical digestion - teeth
Esophagus - peristalsis moves food to stomach

4. The Digestive System II. Upper Digestive System Stomach
Chemical digestion
Hydrochloric acid (HCl)- provides acidic
Environment for pepsin to work best
Pepsin- breaks down protein into amino acids

5. The Digestive System Upper Digestive System Stomach
Mucus protects stomach lining
Cells in stomach lining are quickly replaced
Mechanical digestion - stomach churning

6. The Digestive System Lower Digestive System Small Intestine
Site of chemical digestion
Liver secretes bile into the small intestine
Pancreas secretes enzymes that help break down starches, proteins, and fats
Absorption of nutrients by villi

7. The Digestive System Lower Digestive System Large intestine
Bacteria feed and produce vitamins for the body
Water is absorbed
Passes wastes (undigested food) to rectum, then anus for disposal.

9. Digestive System

11. Excretory System

12. Excretory System Function of the Excretory System
Collect wastes produced by cells and removes the wastes from the body.
Excretion-process of removing waste from the body.

13. Excretory System--Components
Kidneys
Eliminate urea, a chemical that comes from the breakdown of proteins
Eliminate excess water and other waste materials
Contain about a million nephrons which are filters that remove waste from blood and produce urine, the watery fluid that exits our body.

14. Excretory System--Components
Ureters
Narrow tubes that move urine from the kidneys to the urinary bladder (a sac like muscular organ that stores urine)

15. Excretory System--Components
Urethra
A small tube that sends urine out of the body

16. Excretory System--Other organs of excretion
Lungs-the respiratory system removes carbon dioxide and some water from the body.
Skin-the integumentary system removes waste by perspiration
Liver-part of the digestive system and gets rid of toxins in your blood.

17. Excretory System
A = Kidney
B = Ureter
C = Urinary bladder
D = Urethra