9.16.13 Kin 110 class notes- Gumball machine & human example (ATP, CP, fat, protein)- Question of the day:o If the gastrointestinal system is like a washing machine, what molecules are laundry products?- GI system:o Digest, use, store foodo Don’t need to know the parts… oral cavity, esophagus, stomacho Complex polymers to single nutrientso Efficiently absorb the nutrientso Exclude antinutrients (toxins, bacteria)- Point of digestiono Food (polymers, usually solid but not necessarily single nutrients in a watery/aqueous solution what kind of apple? Honey crisp water and simple sugars can only absorb single nutrients- Chunnel between England and Franceo Food not “in” body as it passes through gastrointestinal systemo Prevents infection by separating food from the rest of the body- Mouth:o Liquification (saliva) and mechanical disruption (chewing)o So liquefied sea of smaller pieceso Do you have to chew your food to digest it? No…eat that powerbar whole- Salivary amylase: starcho Break bonds between simple sugarso Leave food in mouth for a min- gets sweeter- Food in mouth causes:o Muscle contraction in stomacho Some stomach cells produce hydrochloric acid- burns hole in clothing in secondso Muscles: transverse, oblique…- A. Acid lowers pH of food from 7 2 (very acidic)o Kills bacteria, viruses, protozoeno Thick mucus layered on stomach, protects the rest of the body from damage- B. Low pH proteins “unwinds” them.o Goes from a clump to a string of spaghettio Need surface area to break down foodo Starch digestion ends because salivary amylase denatured- C. activates pepsin: enzyme that makes protein amino acidso Mechanical action- Fat in food forms large drops (clumps together)o Example: salad dressingo Grinding action of stomach smaller droplets- Stomach grinding action turns large fat drops small dropletso Exit of food from stomach pylorus- Slow down Exit of food through pylorus:o Fiber: makes you feel more fullo Fat: stays in stomach longer, more fullo Stress: pylorus stays closed longero Eat differently before a game than a practiceo Pylorus opens more slowly- In small intestine – immediate problem with acidity of foodo (Baking soda) from pancreas neutralizes acidic food neutralityo sodium bicarbonateo secreted into small intestineo same as baking soda! What what- bile made in liver coats fat droplet, cholesterol, prevents them from forming big drops o stored in the gallbladder, bile makes large fat drops into small bile dropletso removed gallbladder – hard to digest fatty foodso lipases fat smaller componentso laundry detergent – enough bile, can be used as laundry detergent! Does the same thing…- bile absorbed and recycled back to large intestineo recycled back to liver, liver makes new bile, then to gallbladder…starts
View Full Document
Unlocking...