1. Unit 10-Human Body Chapter 38 Digestive and Excretory Systems

2. Nutrients Carbohydrates –Sugars and starches –Body’s 1 st choice for energy Lipids –Fats, oils & waxes –Body’s 2 nd choice for energy Proteins –Body’s building block –Body’s 3 rd choice for energy (only when starving)

3. Nutrients Vitamins –Organic substances –For normal growth & development Minerals –Inorganic substances –For normal growth & development Water –For lubrication, transport, temp control, etc

4. Functions of Digestive system Ingestion (bringing food in) Digestion (breaking food down) –Mechanical (physical) –Chemical Absorption (passing food to blood for transport) Defecation (elimination of indigestible food from body)

5. Digestive organs Mouth (oral cavity): Tongue –For tasting, chewing, swallowing, speech Teeth –Incisors, canines, premolars, molars Salivary glands –Begins digestion of starch Mucus secretions to lubricate

6. Digestive organs Pharynx –Throat; passageway for air & food Esophagus –No digestion, only passageway to stomach Peristalsis –Wavelike contractions that move food through alimentary canal

7. Digestive organs Stomach –J-shaped organ on left side; reservoir for mixing food with gastric chemicals –Chemicals range from mucus to acid Small intestine –Completes digestion & most absorption –Fluids from pancreas & bile from liver added Villi –Fingerlike projections; increase surface area

9. Digestive organs Large intestine (colon) Reabsorbs water (from lubrications) Eliminates indigestible food (wastes) E. coli (bacteria) digest what’s left— usually vitamins & minerals--and it’s absorbed with water

11. Practice

12. Excretory system Functions: Remove cell wastes from blood Balance chemical composition of blood

13. Excretory organs Kidneys –2 bean-shaped organs near waist –Contain millions of nephrons –Tiny units for controlling blood chemistry Ureters –2 tubes carrying urine to… Bladder –for temporary storage Urethra –1 tube leading to outside

14. The nephron of the kidney