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The Digestive System. A Brief Introduction. YouTube Clip: I can't believe it remix ( The Digestion Song) Travis Finlay http://www.youtube.com/watch?v=SyVcyT-fOao. Learning Goals. I understand the function and stages of the digestive system
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A Brief Introduction... YouTube Clip: I can't believe it remix ( The Digestion Song) Travis Finlay http://www.youtube.com/watch?v=SyVcyT-fOao
Learning Goals • I understand the function and stages of the digestive system • I know the structure and function of the organs involved in the digestive system. • I know the diseases associated with the digestive system.
What does the Digestive System do? • Takes in food • Breaks food down into smaller units • Absorbs nutrients • Excretes waste Digestion: The process of breaking down food to provide nutrients and energy for growth, repair and reproduction.
The Four Stages of Digestion • Ingestion: Intake of nutrients • Digestion: Breakdown of nutrients into smaller units by: a. Physical – Mechanical breakdown of food b. Chemical – Enzymes and chemicals that breakdown food 3. Absorption – Taking nutrients into cells 4. Egestion – Excretion of waste
The Digestive Tract • One long tube that extends from the mouth all the way down to the anus • Goblet cells secrete mucus • Madeof epithelial tissue, layers of muscles and nerves • Food moves through by a process called peristalsis. Wave like motion from the alternate contraction/relaxation of smooth muscle in the digestive tract.
Definitions • Mucus – Secreted by goblet cells in the epithelial tissue. Has two functions: 1. Protects the digestive tract from enzymes 2. Allows the digested material to pass through the tract • Accessory Organ – Aids in the process of digestion but food does not actually pass through.
Summary • The digestive system takes in food, breaks it down, absorbs nutrients and excretes waste. • The digestive system is made up of the digestive tract and accessory organs. • The digestive tract is one long tube with opening at either ends and includes the mouth, esophagus, stomach , large intestine, small intestine, and anus. • The digestive tract includes epithelial tissue, smooth muscle tissue, nerves and connective tissues. The smooth muscles can contract and relax involuntarily. • The accessory organs aid in the process of digestion and include the liver, pancreas and gall bladder.
Homework • In class: Questions from textbook page 82 # 2, 3 and 4. • Gizmo on the Digestive System. • - Complete the 5 page handout (Parts A and D) for homework and answer the 5 quiz questions online. • Due Friday in class • QUIZ ON MONDAY