Chapter 36 – Digestive and Excretory System

1. Chapter 36 – Digestive and Excretory System 2/2 Classwork – Copy vocabulary terms from the board Homework 2/2 (due Wednesday) Keep a record of what you eat (breakfast, lunch, dinner) on Tuesday and bring in on Wednesday.

2. Food and Energy Nutrients are substances that the body requires for energy, growth, repair and maintenance. Fuel Other Essential Nutrients Carbohydrates Vitamins Proteins Minerals Fats Water

3. Energy Calories vs. calories When the body breaks down food through digestion, the chemical bonds in nutrients are broken and energy is released. The energy release when bonds break is measured in calories. 1000 calories is equal to 1 Calorie (information found on food labels).

4. Calorie Determination Calories are determined by a process called calorimetry.

5. Energy Requirements The body needs energy to carry out both voluntary (Running, swimming, biking) and involuntary (breathing, growing, blinking) activities. Exercise Calories When you consume more calories than you burn, those calories get store in the body as fat.

6. Body Fuels Carbohydrates Simple sugars (Glucose) Found in fruits, honey and onions Complex Sugars (starch and cellulose) Found in fruits, vegetables, cereal grains, potatoes, and corn.

7. Body Fuels, cont. Proteins Essential Amino Acids (found in foods) Amino Acids (made in the body) Eggs Milk Fish Poultry Beef Contain all of the essential Amino acids Only some are found in plants Proteins Enzymes Antibodies Muscles

8. Body Fuels, Cont Fats (One type of lipid) Used for storing energy, padding and insulating organs, making hormones and cell membranes, and dissolving fat soluble vitamins

9. Essential Nutrients Water Regulates body temperature, and transports gases, nutrients and wastes. Vitamins Fat soluble vitamins – A, D, E, K Stored in body fat and can become toxic in large amounts Water soluble vitamins – B, C Excess amounts are excreted in the urine and can be replaced by the diet. Minerals Naturally occurring substances that are not made by the body (Na, K, Fe, Ca) These substances are needed for nervous system function, muscle contraction, transporting oxygen in the blood and normal immune function.

10. Healthy Eating Habits

11. Nutritional and Health Body Mass Index (BMI) Healthy Adult Weight Range (BMI = 18.5-25.0) (Weight in pounds) (Height in inches)2 • Excess body fat can result in increased risk of: • Heart disease • Osteoarthritis • Type II diabetes

12. Eating Disorders Anorexia Obsession with being thin Bulemia Binge eating followed by behaviors to reduce weight (vomiting, fasting, over-exercising) Abnormal eating habits may result in dehydration, fatigue, organ failure and death.

13. Breaking Down Food Into Nutrients Digestion The body takes in food, breaks it down into molecules that the body can use, and gets rid of undigested molecules and waste. Chemical Digestion – breaking of chemical bonds Complex carbohydrates Simple sugars Proteins Amino acids Fats Fatty Acids Mechanical Digestion – Physical breakdown of food Chewing and churning

14. Starting Digestion – Mouth Mouth • Mechanical breakdown of food by teeth • Chemical breakdown of food by saliva • Contains amylase – an enzyme that breaks down starches • Swallowing • The epiglottis covers the trachea and food moves into the esophagus • Peristalsis begins in the esophagus

15. Starting Digestion – Stomach Stomach • Chemical breakdown of proteins by Gastric juices (HCL and pepsin) • HCL unfolds proteins • Pepsin breaks bonds in proteins to form amino acid chains • Mechanical breakdown occurs as the stomach churns food and mixes it with gastric juices

16. Absorbing Nutrients Absorption of nutrients mostly takes place in the small intestine and is aided by secretions from the liver and pancreas. Liver- Secretes bile that breaks fat globules into tiny fat droplets and aids in the absorption of vitamins A, D, E, and K Gallbladder – Stores bile Pancreas – Secretes lipases to breakdown fat droplets

17. Other Important Functions of the Liver and Pancreas Homeostasis – Blood sugar regulation The liver converts extra sugar into glycogen (a stored source of energy). When energy is needed, the liver breaks down glycogen and releases glucose. The pancreas makes insulin that regulates the conversion of glycogen to glucose. Storage and Detoxification Besides glycogen, the liver stores fat soluble vitamins and iron. It also, removes poisons from the bloodstream and monitors the production of cholesterol.

18. Small Intestine The small intestine further breaks down food and reabsorbs nutrients through the villi and microvilli that cover its lining. Capillaries in the villi, transport nutrients to the blood stream.

19. Removing Waste The Large Intestine (No digestion occurs here) • Water and minerals are absorbed • Vitamins B and K are synthesized here by bacteria • Bacteria transform undigested material into feces

20. Excretion Osmotic (amount of dissolved particles) and pH balance of the blood is maintained through excretion. Excretory Organs Skin removes excess water, salts and nitrogen Lungs remove carbon dioxide Kidneys primary excretory organs that remove all of the above and other cellular wastes.

21. Water Most chemical reactions must take place in water • Water absorbs and distributes heat • Water transports gases, nutrients and wastes in and out of cells DRINK WATER A health person should drink at least 2.5qt of water each day to replenish the water lost through excretion

22. Cleaning the Blood Kidneys contain Nephronsthat carry out 3 main functions: • Filtration of blood (Glomerulus) • Reabsorption of water and other nutrients (renaltubule) • Secretion of wastes, toxins and water (collecting ducts)

23. Urinary Excretion The resulting product of filtration, absorption and secretion is Urine. Urine flows through: • Ureters • Bladder • Urethra

24. Kidney Disease Kidneys are vital to maintaining homeostasis, so damage to the kidneys may eventually become life threatening. Most common causes of kidney damage: • Infection • Diabetes • High blood pressure • Autoimmune diseases

25. Treatment for Kidney Disease Dialysis (not a cure) A process for filtering blood to remove substances from the blood. Kidney Transplant