PLB 115 1st Edition Lecture 8Previous Notes’ OutlineRespiratory systemI. Lungs a. Functions, componentsII. Capillaries & AlveoliIII. Problems with lung functionCurrent Notes’ OutlineDigestive SystemI. Mechanical & Chemical processinga. Mouthb. Stomachc. Small intestineII. PancreasIII. LiverIV. Large intestineV. Nutrient uptakeVI. LiverDigestive SystemDigestive System: Processes & distributes nutrientso Mechanical Processing, Chemical Processing, Nutrient Uptake, Chemical Alteration- A muscular tube (esophagus) & glands that secrete digestive juices with enzymes & acidsMechanical & Chemical Processing: Large pieces of food broken down to individual molecules that can be easily absorbed into the blood stream- Mechanical: Chewing in the oral cavity (mouth) to make food smaller, more compact- increasing total surface areaThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o In mouth:(Mechanical & chemical processing) Food mixes with water (dissolves stuff) & saliva (contains enzyme amylase that begins to break down starch)o In stomach: (Mechanical & Chemical processing) Food churned by stomach muscle’s contractions to mix food with digestive juices that contain water, enzymes (like Pepin that beak down proteins) & hydrochloric acid (low pH-2 that denatures proteins & kills foreign organisms)o Small intestine: (Chemical processing) Completes digestion with added digestive juices & its enzymes that break down all food (carbs, proteins, fats) 1st part: Duodenum- Produces hormones that regulate release of food from stomach, digestive juices from pancreas, bile from gall bladder- Produces own & receives digestive enzymes (& bicarbonate ions) from pancreasPancreas: Has enzymes that complete chemical processing- Bicarbonate ions neutralize low pH of food from stomachLiver: Bile emulsifies fats (breaks down to smaller fat globules)- Increases surface area, allows digestive enzymes greater access to fatsLarge intestine (Colon): LONG- 1.5 Meters. Undigested food comes here from small intestine- Reabsorb watero Contains bacteria that use undigested food& produce vitamins (K)Nutrient Uptake: Absorption of small food molecules into blood stream- Occurs in small intestine lining - Requires large suface area- small intestine is 6-8 meters long (folded tightly)o Lining has millions of villi: finger-like projections that increase surface area  Villi: Each villus has several capillaries & lymphatic vessel: lacteal- Absorption: Diffusion of water & small ions from gut to blood in capillaries, carrier molecules help move sugars & amino acids into capillaries, fatty acids/glycerol enter intestine to form fats & transported to lacteals in villi to enter blood from lymphatic systemLiver’s Chemical Alterations- Hepatic portal vein takes nutrient-rich blood from intestine to liver- Foreign substances filtered out- Toxic substances de-toxified: Plant toxins, ethyl alcoholEnzymes modify nutrient molecules• Glucose stored as glycogen • Glycogen converted to glucose (and released as needed)• Some amino acids converted to other amino acids • Amino groups removed so amino acids can be used to provide body with energy • (Some) Amino groups converted to