TAILIEUCHUNG - Lecture Biology 25 (Human Biology): Chapter 5 - Prof. Gonsalves
Chapter 5 provides knowledge of digestive system & nutrition. The following will be discussed in this chapter: The digestive system, three accessory organs, digestive enzymes, homeostasis, nutrition. | Chapter 5 (and a bit of Chp 4) Biology 25: Human Biology Prof. Gonsalves Los Angeles City College Loosely Based on Mader’s Human Biology,7th edition Integumentary System Components: Hair, skin, and nails. Functions: Protects the body from: Infection: Barrier to microbes. Mechanical injury Excessive heat or cold: Thermoregulation Water loss Communication: Receives stimuli from environment Gives out subtle signals (blushing, etc.). Homeostatic Role: Helps maintain constant body temperature. 1. Digestive System Components: Mouth, salivary glands, throat, esophagus, stomach, intestines, liver, gallbladder, pancreas, rectum, and anus. Functions: Ingest and mechanically break down food. Digest food: Stomach and small intestine mainly. Absorb nutrients and water. Eliminate waste. Homeostatic Roles: Supplies energy for life’s activities. Supplies building blocks for macromolecules Stages of Food Processing 1. Ingestion: The act of eating. Usually involves placing food in mouth or oral cavity. 2. Digestion: Macromolecules in food (fats, proteins, polysaccharides, etc.) are too large to be absorbed by digestive system. Must be broken down into small molecules (amino acids, simple sugars, etc.) so they can be absorbed and utilized by the body. Involves two processes: Mechanical: Chewing and churning. Chemical: Enzymatic breakdown of food. Stages of Food Processing 3. Absorption: Cells lining the digestive cavity take up building blocks (simple sugars, amino acids, etc.), which then enter the bloodstream. Circulatory system distributes nutrients in blood to cells throughout the body. 4. Elimination: Undigested food materials are discharged from body. Stages of Food Processing Parts of the Human Digestive System Alimentary canal: Long tube like structure. Mouth Tongue Pharynx (throat) Esophagus Stomach Small intestine Large intestine Rectum Anus Digestive glands: Produce enzymes, bile, and other substances important for digestion. Salivary glands Pancreas Liver and gallbladder
đang nạp các trang xem trước
