The Blood Vessels and Blood Pressure - The Blood Vessels and Blood Pressure Blood flow o Blood is constantly reconditioned so composition remains

The Blood Vessels and Blood Pressure - The Blood Vessels...

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The Blood Vessels and Blood PressureBlood flowoBlood is constantly reconditioned so composition remains relatively constant. Oxygen added, and carbon dioxide is removed. Ion concentrations are kept constant (RBC’s are very sensitive). Ion conc. Is just about the only constant thing in the bloodoBlood flow to organs can be adjusted according to metabolic needsoThe brain can least tolerate disrupted supplyThe brain burns sugars (glucose) exclusively. The rest of the body can burn proteins, fatty acids, etc. for energy. The brain can’t do thisoFIGURE 10.1: distribution of cardiac output at restThe digestive system gets the most blood (excluding the lungs)Kidneys remove waste/poison so they get a lot of bloodoFlow ratethrough a vessel = volume of blood passing through per unit of time:directly proportional to the pressure gradientinversely proportional to vascular resistanceF=dP/RF= flow rate of blood through a vesseldP= pressure gradientR=resistance of blood vesselsoPressure gradient: the pressure difference between the beginning and end of a vesselThe blood flows from an area of higher pressure to areas of lower pressureoResistance: the measure of opposition of blood flow through a vesselMajor determinant of resistance to flow is the vessel’s radiusSlight changes in the radius produces significant changes in the blood flowR is proportional to oFIGURE 10.2 and 10.3: relationship of R and F to vessel radiusBlood vesselsoArteries: carry blood away from the heart to tissuesSpecialized to serve as rapid-tissue passageways for blood from the heart to the organsDue to large radius, arteries offer little resistance to blood flowAct as a pressure reservoir to provide driving force for blood when the heart is relaxing (FIGURE 10.6)Arterial wall contains:
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