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where does the arterial pressure fluctate between?
systolic pressure (SP) and diastolic pressure (DP)
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where is the blood pressure the highest in? where is the steepest drop?
- aorta, declines throughout pathway and is 0mm Hg in right atrium.
- steepest drop in arterioles
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what is pulse pressure?
diminishes over distance, eliminated at the capillary level
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what are the capillary pressures?
drops from 35 to 18mm Hg along capillary length
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why are low capillary pressures desirable?
- High BP would rupture fragile, thin walled capillaries
- most very permeable, so low pressure forces filtrate into interstitial spaces
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what is the function of capillary pressures that cause filtration out of bloodstream and into tissues?
- maintains communication between plasma and IF
- speeds distribution of nutrients, hormones and gases
- assists movement of insoluble molecules
- flushes bacterial toxins and other chemicals to lymphatic tissues for immune response
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what are the distribution functions of the blood?
- delivering O2 and nutrients to body cells
- transporting metabolic wastes to lungs and kidneys for elimination
- transporting hormones from endocrine organs to target organs
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what are the regulation functions of blood?
- maintain body temp
- maintain normal pH using buffers
- maintain adequate fluid volume in circulatory system
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what are the protective functions of blood?
- prevent blood loss (clot formation)
- prevent infection (WBC and antibodies)
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what is the blood composition?
- plasma: non-living fluid matrix (55%)
- formed elements: living blood cells (45%); erthrocytes (on bottom) and leukocytes and platelets in buffy coat (middle thin layer less than 1%)
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plasma composition
- 90% water, 6-8% plasma proteins
- electrolytes
- nutrients
- wastes
- dissoved oxgyen and carbon dioxide
- hormones
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what are some general functions of plasma proteins?
- colloid osmotic pressure: pull water into circulatory system
- maintain pH
- increase blood viscosity
- fuel during starvation
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what is serum?
plasma, minus the clotting proteins
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where are the plasma proteins synthesized?
90% of it by liver, except some globulins by lymphocytes
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what are three major types of plasma proteins?
- albumins (most): contribute to colloid osmotic pressure
- globulins: transport proteins and antibodies
- fibrinogen: converts to fibrin
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how much does RBC make up formed elements?
99.9%
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what is the advantages of biconcave shape?
- increased surface area increases rate of diffusion
- increased flexibility
- spectrin provides flexibility to change chape
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what is the function of hemoglobin?
transports oxgyen and carbon dioxide; oxygen binds to heme; carbon dioxide binds to globular subunits
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when does oxyhemoglobin occur? deoxyhemoglobin
- high plasma O2 causes hemoglobin to gain o2 until saturated, occurs as blood circulates through lung capillaries
- low plasma 02 and high CO2, causes hemoglobin to release O2; occurs as blood circulates through systemic capillaries
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where does erthropoeisis occur?
- RBC production is in the red bone marroe or myeloid tissue.
- red marrow consists of mainly reticular conective tissue and blood sinusoids and yellow marrow is made up of fat cells
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RBC production
- erythrocytes and leukocytes develop from same stem cells (hematopoietic) in bone marrow
- myeloid stem cell transformed into proerythroblast
- 15 days proerthyroblasts develop into reticulocytes (young RBC)
- reticulocytes enter bloodstream; in 2 days, mature RBC when ribosome degraded
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how are RBC disposed?
- if RBC hemolyze in bloodstream, Hb breaks down in blood and is filtered out by the kidneys
- most RBCs Hb components are recycled; spleen macrophages remove old erthrocytes, liver metabolizes byproducts from breakdown of erthrocytes
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