The nature of the arteriolar resistance and its distribution in the body remain the fundamental problem in the study of arterial hypertension in man. Since the cardiac output is normal in this state (1), the " average arteriolar resistance " at rest must be increased. The extent to which the peripheral resistance is increased in various tissues can be determined by comparing the blood flow in t...

introduction : cerebral autoregulation (ca) and mean cerebral blood flow velocity in males and females are still under controversy. the present study was scheduled to address the effect of sex on these parameters. materials and methods : the present study was interventional and performed on 30 healthy volunteers (15 males aging from 20-30 yrs and mean age of 23.9±3 years old and 15 females agin...

In two-kidney, one clip (2K1C) renovascular hypertension, blood flow is reduced to the clipped but not to the nonclipped kidney, despite elevated angiotensin II. To determine possible interactions between endothelium-derived nitric oxide and angiotensin, we studied bilateral renal blood flow using radioactive microspheres in anesthetized 2K1C hypertensive rats 4 weeks after clipping. We studied...

BACKGROUND A mathematical model to help explain the hemodynamic characteristics of perforator flaps based on blood flow resistance systems within the flap will serve as a theoretical guide for the future study and clinical applications of these flaps. METHODS There are 3 major blood flow resistance network systems of a perforator flap. These were defined as the blood flow resistance of an ana...

background: the mechanisms underlying cerebral hypercapnic vasodilatation are not fully understood.   objective: to investigate the role of nitric oxide (no) and atp-sensitive potassium (k atp ) channels in basal blood flow regulation and hypercapnia-induced vasodilatation in rabbit cerebral blood vessels.   methods: the change in cerebral blood flow was measured by a laser doppler flowmeter in...

Activation of sympathetic adrenergic postganglionic fibers that release norepinephrine at the neuromuscular junction can influence resistance, capacitance, and exchange functions in the microcirculation. Although the predominant response is an increase in precapillary resistance that reduces blood flow through the tissue (at constant pressure perfusion), there are two distinct components that c...

The effect of the heart rate and myocardial contractile force on the extravascular resistance to blood flow of the left anterior descending coronary artery (LAD) was evaluated in 15 mongrel dogs anesthetized with sodium pentobarbital. The LAD was maximally dilated by intracoronary infusion of adenosine, which precluded the influence of vasomotor tone. Increases in the heart rate and myocardial ...