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Unformatted text preview: Digestion Energy we use to drive reactions necessary for life comes from food o Cellular respiration Organic Compounds + Oxygen -> Carbon Dioxide + Water+ Energy o Carbs, fats, and proteins can all be consumed as fuel Carbs are the first to be consumed Primary source of fuel to get ATP o Fats consumed after carbs are used up o Proteins consumed after carbs and fats are used up Main stages of food processing: Ingestions: eating Digestion: Breaking down macromolecules - Monomers Absorption: Extracting nutrients from food into body Elimination: Getting rid of waste Digestive Methods Intracellular -> Within a cell o Phagocytosis, vacuole-lysosome fusion Extracellular -> outside of a cell o Specialized compartments and organs used (digestive system) Digestive system is continuous with the external environment o Allows for mass consumption and storage of ingested food o The inside of our digestive tract is technically outside of our bodies Digestion Essentially a tube that runs through our bodies Alimentary canal (tube within a tube) Advantage of canal: We can ingest more food before a previous meal is digested o Peristalsis: Rhythmic smooth muscle contraction Food moves in a one way direction o Each organ of the digestive system has a specialized function to aid in processing of food Foods first stop: the oral cavity, pharynx and the esophagus Begins in the mouth Physical standpoint: Chewing breaks down food, increasing the surface area Food in mouth, anticipation of food: Production of saliva from salivary glands Protects the lining of the mouth Lubricates food for easy swallowing Chemical digestion: Carbs broken down o Salivary amylase: Breaks down carbs, hydrolyzes large polysaccharides Tongue: Shapes food into a bolus and pushes it to the pharynx (Swallowing) o Pharynx: area that opens up to the trachea and esophagus...
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