Exam 2 Study Guide

Exam 2 Study Guide - Exam 2 Study Guide Ch. 40- Animal Form...

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Exam 2 Study Guide Surface Area to Volume Ratio- Body SA increases w/ body length squared Mass increases w/ body length cubed As body gets larger, ratio gets smaller Maximize Ratio To increase exchange surface in order to obtain or expel something EX: lungs, GI tract Minimize Ratio To decrease exchange surface and retain things (nutrients, oxygen) EX: Lower SA:V allows for better heat retention Ectotherms- Gain most of their heat from their surroundings Low Metabolic Rate—cannot generate enough heat to keep body warm (or effect temp) Advantages: Cheap, can consume much less food Ecotherms can live in extreme climates where food is limited Endotherms - Can use metabolic heat to regulate body temperatures Advantages: Can perform vigorous activity for much longer Better adapted to land Disadvantages: Expensive! Takes lots of food to keep body warm Homeostasis- Steady state condition of body Negative Feedback- a primary mech in homeostasis * A change in a physiological variable that is being monitored triggers a response that counteracts the initial flucuation * Prevents small changes from becoming too large Positive Feedback- * Change in a variable that triggers mechanisms that amplify rather than reverse the change EX: Baby Head pressure on uterine opening during childbirth amplifies the contractions Thermoregulation Def- regulation of a body’s internal temperature Countercurrent Exchange - arrangement of blood vessels that reduce heat loss in endotherms
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** Like how lungs/gills work Ch. 41- Animal Nutrition Essential Nutrients: Amino Acids- 20 needed, 8 essential Fatty Acids- Saturated and Unsaturated Vitamins- 13 essential, need only in low amounts, either water or fat soluble Minerals- Ca, P, Fe, Mg- enzyme cofactors, body function *Scurvy—deficiency in collagen synthesis, spongy gums, bleeding membranes, death Get?—too little Vitamin C Why Rich kids in 20 th century? – pasteurization removes Vitamin C from milk The Digestive System 4 stages of Food Processing: 1. Ingestion- eating, chewing 3. Absorption- small intestine 4. Elimination- Large intestine (water absorption) Stomach To Activate Pepsin: PNS Gastrin Pepsinogen (needs HCl) Pepsin *secreted as inactive form pepsinogen, other cells release HCl which converts it to pepsin End Product Inhibition—HCl suppresses the release of gastrin Positive Feedback—Once pepsinogen is activated by acid, activation occurs rapidly b/c pepsin can activate pepsinogen also. Small intestine
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This note was uploaded on 10/08/2008 for the course EBIO 1220 taught by Professor Demig-addams during the Spring '07 term at Colorado.

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Exam 2 Study Guide - Exam 2 Study Guide Ch. 40- Animal Form...

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