BIOL 129 Lecture Notes - Lecture 7: Vasoconstriction, Retroperitoneal Space, Peritonitis
Document Summary
Processes food, extracts nutrients, and eliminates waste. Provides the fuel that keeps body"s cells running and the building blocks needed for cell growth and repair. Disassembly line : breaks down complex molecules to simple forms we can absorb and reuse; disposal of worthless and toxic materials. (1) gastrointestinal tract (gi tract): tube extending from mouth to anus, about 9 meters long. Ingestion : occurs when materials enter the gi tract via mouth. Chemical digestion : chemical breakdown (via enzymes) of via. Secretion : release of h2o, acids, enzymes, buffers, salts to facilitate. Absorption : uptake of nutrient molecules, first into the digestive epithelial. Four main layers (from innermost to outermost from lumen toward cells and then into the bloodstream. Where we want to maximize surface area. Want to reduce as much damage and abrasion as possible. Small intestine wants columnar cells for a lot of surface area to absorb more nutrients.
