BSCI 202 study guide exam 1

BSCI 202 study guide exam 1 - Introduction Body fluids o...

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Introduction - Body fluids o Intracellular – fluid inside the cell o Extracellular – fluid outside of the cell (plasma and interstitial are extracellular) o Interstitial – fluid in between cells o Total body fluid - Homeostasis o Process of maintaining stable internal environment compatible for life o Most organ systems contribute to homeostasis besides reproduction o Negative feedback is the main control of homeostasis Shuts of the original stimulus or reduces its intensity Works like a thermostat Brings us back to our normal set levels Body temperature increase: blood flow to the skin increases; Body temperature decrease: blood flow to skin decreases o Positive feedback loop Cause a rapid change in a variable Not a common mechanism for maintaining homeostasis Response increases the original stimulus as opposed to canceling it out Increases the original stimulus to push the variable farther Stimulus must end for the response to end Blood clotting is an example – formation of a platelet plug Blood - Components o Living cells called formed elements Erythrocytes – red blood cells Transport oxygen and carbon dioxide Leukocytes – white blood cells Defend body against pathogens
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Platelets – cell fragments Important in blood clotting o Non-living matrix Plasma – fluid and solutes - Hematocrit o Percentage of erythrocytes (usually 45%) o Buffy coat – contains leukocytes and platelets Thin, whitish layer between the erythrocytes and plasma o Plasma rises to the top (55%) - Blood plasma o 3 major classes of plasma proteins (synthesized in the liver, except some globulins synthesized by lymphocytes); blood plasma is 6-8% proteins which increase osmotic pressure, buffer H+, increase blood viscosity, provide fuel during starvation Albumins – major contributor to plasma oncotic osmotic pressure and act as carriers Globulins – carriers, clotting factors, precursor proteins (angiotensinogen), immunoglobulin’s Fibrinogen – blood clotting - Erythrocytes o RBCs o Main function is to carry oxygen o Anatomy of circulating RBCs Biconcave disk – large surface area which favors diffusion Essentially bags of hemoglobin Anucleate Contain very few organelles No mitochondria No anaerobic glycolysis o Flexible membrane o Also functions to maintain osmolarity and blood/plasma pH o Hemoglobin
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Carries oxygen Binds strongly but reversibly to oxygen (fetal hemoglobin has a much stronger affinity to oxygen) Each molecule has 4 oxygen binding sites Iron-containing protein Can also bind to carbon dioxide and H+ - Anemia o Reduced oxygen carrying capacity o Dietary – iron deficiency anemia o Hemorrhagic – bleeding o Hemolytic – malaria or sickle cell o Aplastic – bone marrow defect o Renal – kidney disease - Leukocytes o Granulocytes Granules in their cytoplasm can be stained Possess lobed nuclei Neutrophils Phagocytes at infections
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This note was uploaded on 12/01/2010 for the course BSCI 202 taught by Professor Opoku during the Fall '08 term at Maryland.

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BSCI 202 study guide exam 1 - Introduction Body fluids o...

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