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Terms in this set (13)

Any fluid driven by a pump through a circuit of closed channels operates under pressure, and the nearer the fluid is to the pump, the greater the pressure exerted on the fluid. The dynamics of blood flow in blood vessels is no exception, and blood flows through the blood vessels along a pressure gradient, always moving from higher- to lower-pressure areas.
Arteries must be able to endure high pressure of blood, from the aorta to the ends of the arterioles is about 60 mm Hg
Capillaries are fragile and high pressures would rupture them, and most capillaries are extremely permeable and thus even the low capillary pressure forces solute-containing fluids (filtrate) out of the bloodstream into the interstitial space.
Venous blood pressure is steady and changes very little during the cardiac cycle. The pressure gradient in the veins, from venules to the termini of the venae cavae, is only about 15 mm Hg
•Arteries receive blood from the heart, the blood they receive is under a lot of pressure. Can you picture how much pressure the arteries near the heart (like the pulmonary trunk and the aorta) have to withstand every time the ventricles squirt out a load of blood? At the same time, this pressure helps the blood move through the arteries-- even when the arteries are running in opposition to gravity
•The veins only receive the blood after it has travelled quite far from the heart. The blood pressure in the veins is thus much less; the blood is certainly much less likely to burst through walls of the veins than arteries. Also, because the blood pressure is small in the veins, it is not going to be enough to return all that blood to the heart; in fact, the blood could easily back up or collect in these vessels
Hypertension - high blood pressure, condition of sustained arterial pressure of 140/90 or higher, and the higher the pressure, the greater the risk for serious cardiovascular problems.
•Causes
Heredity: Hypertension runs in families. Children of hypertensive parents are twice as likely to develop hypertension as are children of normotensive parents, and more blacks than whites are hypertensive. Many of the factors listed here require a genetic predisposition, and the course of the disease varies in different population groups.
Diet: Dietary factors that contribute to hypertension include high intakes of salt (NaCl), saturated fat, and cholesterol and deficiencies in certain metal ions
Obesity.
Age: Clinical signs of the disease usually appear after age 40.
Diabetes mellitus. Stress: Particularly at risk are "hot reactors," people whose blood pressure zooms upward during every stressful event. Smoking/Nicotine
•strains the heart and damages the arteries.Prolonged hypertension is the major cause of heart failure, vascular disease, renal failure, and stroke. Because the heart is forced to pump against greater resistance, it must work harder, and in time the myocardium enlarges.When finally strained beyond its capacity to respond, the heart weakens and its walls become flabby. Hypertension also ravages the blood vessels, accelerating the progress of atherosclerosis the vessels become increasingly blocked, blood flow to the tissues becomes inadequate and vascular complications appear in the brain, heart, kidneys, and retinas of the eyes.