BISC 101 Lecture Notes - Lecture 16: Gastrovascular Cavity, Cecum, Parietal Cell
14 Mar 2016
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Document Summary
Food provides chemical energy (for atp synthesis), raw materials for biosynthesis of complex molecules, and essential nutrients. Complex, linear tube-like, digestive systems allow for specialisation of function to increase digestive efficiency. Food intake balanced with nutrient and energy demand (homeostasis) (obesity) Animals can obtain food in a number of ways. Substrate feeders: live in or on their food source. Fluid feeders: suck nutrient-rich fluid from a loving host. Suspension feeders: sift small food particles from water (whale) Bulk feeders (most animals): ingest relatively large pieces of food (python) Digestion (food processing) occurs in specialised compartments (to avoid self-digestion) Cells engulf food by phago/pinocytosis into food vacuoles where"s enzymes break down. Extracellular digestion: hydrolysis of food in compartments that are continuous with the environment (gastrovascular cavity or digestive tract) Organisation into specialised compartments (stomach, crop, caeca) Carnivores: large pointed canines, jagged premolars and molars. Herbivores: flattened incisors/canines, molars with broad ridged surfaces. Elastic, muscular wall (food storage, churning of food)
