oct 30& nov 1.2
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where does the arterial pressure fluctate between?
systolic pressure (SP) and diastolic pressure (DP)
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
what is pulse pressure?
diminishes over distance, eliminated at the capillary level
what are the capillary pressures?
drops from 35 to 18mm Hg along capillary length
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
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
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
what are the regulation functions of blood?
- maintain body temp
- maintain normal pH using buffers
- maintain adequate fluid volume in circulatory system
what are the protective functions of blood?
- prevent blood loss (clot formation)
- prevent infection (WBC and antibodies)
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%)
- 90% water, 6-8% plasma proteins
- dissoved oxgyen and carbon dioxide
what are some general functions of plasma proteins?
- colloid osmotic pressure: pull water into circulatory system
- maintain pH
- increase blood viscosity
- fuel during starvation
what is serum?
plasma, minus the clotting proteins
where are the plasma proteins synthesized?
90% of it by liver, except some globulins by lymphocytes
what are three major types of plasma proteins?
- albumins (most): contribute to colloid osmotic pressure
- globulins: transport proteins and antibodies
- fibrinogen: converts to fibrin
how much does RBC make up formed elements?
what is the advantages of biconcave shape?
- increased surface area increases rate of diffusion
- increased flexibility
- spectrin provides flexibility to change chape
what is the function of hemoglobin?
transports oxgyen and carbon dioxide; oxygen binds to heme; carbon dioxide binds to globular subunits
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
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
- 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
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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