1. The Digestive and Excretory Systems

2. The Digestive System The functionof the digestive system is to convert food into simpler substances (molecules) that can be absorbed and used by cells in the body

3. The Digestive System 1.Path of food through the digestive tract. a. mouth b. Esophogus c. Stomach d. Small intestine e. Large intestine

4. The Digestive System a. Mouth – mechanical breakdown of food with physical and chemical breakdown via saliva. Food is broken down into a thick pasty substance called bolus.

5. The Digestive System b. Esophogus – The bolus is transported from the mouth to the stomach via the esophogus. To do this, the esophogus contracts rythmically. These contractions are called peristalis.

6. The Digestive System c. Stomach – combination of mechanical digestion by grinding and chemical digestion. The stomach has a ribbed inner lining to grind the food. Chemicals such as hydrochloric acid help break down the food.

7. The Digestive System d. Small intestine – the most digestion and nutrient absorption occurs here. i. pancreas – produces digestive enzymes ii. Liver – produces bile to break down fat iii. Gall bladder – stores bile

8. The Digestive System e. Large Intestine – removes water from undigested material.

9. The Excretory System The function of the excretory system is to maintain homeostasis by maintaining water balance.

10. The Excretory System 1.Excretory Organs a.Lungs – excrete carbon dioxide and water. b.Skin – excretes excess salt and water

11. The Excretory System 2. Kidneys are the main organs of the excretory system. a. Remove waste products from blood. b. Maintain blood pH. c. Regulate water content of the blood.

12. The Excretory System d. Kidneys are on the dorsal side of the body. i. it takes approximately 45 minutes for the kidney to filter the body’s blood supply. ii. The filtered waste travels through the ureter. iii. The filtered waste is stored in the urinary bladder.