Chapter 14 Digestion, Respiration & Excretion

I.The Digestive System A.Functions 1. Digestion breaks down food so nutrients can be absorbed and moved into the blood. a) Nutrients – substances in food that provide energy and materials for cell development, growth, and repair 2. Digestion is both mechanical and chemical

B.Enzymes 1. Enzyme – a type of protein that speeds up the rate of a chemical reaction in your body. a) They help digest carbohydrates, proteins and fats b) Enzymes are made in salivary glands, stomach, small intestine & pancreas.

C.Organs of the Digestive System 1. Digestive Tract a) mouth b) esophagus -peristalsis – waves of muscle contractions c) stomach d) small intestine -villi – fingerlike projections e) large intestine

2. Accessory Organs a) tongue b) teeth c) salivary glands d) liver e) gall bladder f) pancreas D.Bacteria -Bacteria live in organs in your body like your mouth & large intestine. Some are beneficial to digestion.

II.Nutrition A.Classes of Nutrients 1. Proteins a) Your body uses proteins for replacement and repair of body cells and for growth b) ex. Meats, poultry, eggs, fish, peas, beans and nuts 2. Carbohydrates a) They are the main sources for energy b) ex. Sugar, starch, fiber

3. Fats (lipids) a) provide a lot of energy for the body b) ex. Butter, oils 4. Vitamins a) Organic nutrients needed in small quantities for growth, regulating body functions, and preventing some diseases.

5. Minerals a) Nutrients that lack carbon and regulate many chemical reactions in your body b) ex. Calcium, phosphorus 6. Water

B.Food Groups -No naturally occurring food has every nutrient; you need to eat a variety of foods. 1. Food PyramidFood Pyramid (back page of notes)

III.The Respiratory System A.Functions 1. It brings O 2 from air into the body. 2. It takes O 2 from lungs to individual cells. 3. It carries CO 2 from cells to lungs. 4. It gets rid of CO 2 from lungs to air.

B.Organs of Respiratory System 1. Pharynx – tube-like passageway for food, liquid, & air 2. Trachea 3. Bronchi – two short tubes at the end of the trachea where air enters lungs 4. Alveoli – thin wall sacs. Oxygen moves through walls of the alveoli and through walls of capillaries into the blood.

C.Why do you breathe? 1. Inhaling and Exhaling a) Diaphragm – muscles that contract and relax helping gases into and out of the lungs

D.Diseases and Disorders of Respiratory System 1. Respiratory Infections 2. Chronic Bronchitis 3. Emphysema 4. Lung Cancer 5. Asthma

IV.The Excretory System A.Functions of the Excretory System 1. Rids solid wastes and liquids from digestive system. 2. Rids CO 2 from respiratory system. 3. Rids salt and other substances from skin. 4. Rids excess water, wastes and salts from urinary system.

B.The Urinary System 1. Regulation of Fluid Levels 2. Organs of the Urinary System a) 2 kidneys – filter blood that contains wastes collected from cells. b) ureter – tubes that lead each kidney to the bladder c) bladder – elastic, muscular organ that holds urine until it leaves the body d) urethra – carries urine from bladder outside the body

C.Urinary Diseases and Disorders 1. Dialysis – artificial kidney machine that filters blood when neither kidney works