final exam study guide for anatomy

final exam study guide for anatomy - Introduction -...

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Introduction - 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 Platelets – cell fragments Important in blood clotting o Non-living matrix Plasma – fluid and solutes - Hematocrit o Percentage of erythrocytes (usually 45%)
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o Buffy coat – contains leukocytes and platelets Thin, whitish layer between the erythrocytes and plasma o Plasma rises to the top (55%) - Anemia o Reduced oxygen carrying capacity 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 o Agranulocytes Lack visible cytoplasmic granules Nuclei are spherical, oval, or kidney-shaped Lymphocytes Nucleus fills most of the cell Play an important role in the immune response 3 types: o B Associate with antibodies Can become plasma cells and secrete the antibodies or memory B cells Contact antigens then become a plasma cell Antibodies mark invaders for destruction Exposure to antigen causes clonal selection (humoral immunity) Leukocytosis Indicates infection
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Leukopenia Abnormally low amount of leukocytes Commonly caused by certain drugs such as coricosteroids and anticancer agents - Hematopoiesis o Blood cell formation o Occurs in red bone marrow o Hemocytoblast differentiation Lymphoid stem cell produce lymphocytes Myeloid stem cell produces all other formed elements Erythrocytes and leukocytes develop from the same stem cells in bone marrow; Hematopoietic stem cells o Erythrocyte synthesis stimulated by erythropoietin Secreted fro m the kidneys under conditions of low oxygen levels in blood flowing to the kidneys - White blood cell and platelet formation Thrombopoietin stimulates production of platelets - Hemostasis: common pathway o Stoppage of bleeding resulting from a break in a blood vessel Dissolving a clot o Requires another cascade initiated by the exposure of collagen
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final exam study guide for anatomy - Introduction -...

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