The Digestive System

1. The Digestive System Ch. 2.2 Notes Part 2

2. Enzyme – protein that speeds up reactions • The Digestive System = long tube • Bolus – ball of food 4 Stages of Digestion

3. Stage 1 – Ingesting • taking a bite or sip • Peristalsis is the muscular contractions that help keep things moving along the tube Ingesting

4. Stage 2 – Digesting • Starts when we chew • Mechanical digestion – grinding with teeth Digesting

5. Chemical digestion – saliva • amylase enzyme breaks down carbohydrates • Stomach acid – pepsin enzyme – breaks down protein • Start of Small intestine – duodenum – connects to the pancreas, liver and gall bladder – adding more digestive enzymes • Bile – to break down fats • Gastric juice – stomach acid, mucus and enzymes • Mucus – protects tissue from digestion • Chyme – liquid nutrients in the stomach • Sphincter – round muscles control movement of chime Chemical digestion

6. Stage 3 – Absorption • Small intestines take in nutrients • Covered in villi and microvilli to increase surface area • Large intestine – reabsorbs water • Bacteria help in digestion – Vitamin K Absorption

8. Stage 4 – Eliminating • Wastes are released from body • Solid waste – feces – Digestive System • Liquid waste – urine –Excretory System • Gas waste – CO2 – lungs – Respiratory System Elimination

9. Mouth - pharynx – epiglottis – esophagus – stomach – small intestine (duodenum) – large intestine – rectum – anus Pathway through the Digestive System

10. Urinary tract • Parts include: 2 kidneys – ureters – bladder – urethra Excretory System

11. Obesity – over eating – diabetes • Anorexia nervosa – restricting the intake of food, exercising too much, misusing laxatives • Bulimia nervosa – getting rid of food before digestion takes place(vomit), exercising too much, misusing laxatives Eating Disorders

12. Textbook Questions P.81 # 1-10, & 13, 18 Your Turn