Mean arterial pressure is directly influenced by both cardiac output and total peripheral resistance, while arterial pulse pressure is directly affected by stroke volume but inversely affected by arterial compliance.

Capillary blood flow is mainly regulated by the contraction of arterioles, with the capillary endothelium being responsible for producing NO and PGI2, which relax vascular smooth muscles.

Movement of water and small solutes between the vascular and interstitial fluid compartments primarily occurs through capillary pores via diffusion, filtration, and absorption. Molecules larger than approximately 60 kD are generally confined to the vascular compartment. Lipid-soluble substances, such as CO2 and O2, can pass directly through the lipid membranes of the capillary, and the rate of transfer is directly proportional to their lipid solubility. Large molecules can be transported across the capillary wall in vesicles through pinocytosis, which are formed from the capillary's lipid membrane.

Starling's equation describes capillary filtration and absorption, with filtration occurring when the algebraic sum of the relevant terms is positive and absorption occurring when it is negative.

Fluid and protein that escape from blood capillaries enter lymphatic capillaries and are transported back to the blood vascular compartment via the lymphatic system.

Various physical factors influence coronary arterial blood flow, including blood viscosity, frictional resistance of vessel walls, aortic pressure, and extravascular compression of vessels within the walls of the left ventricle. During ventricular systole, left coronary arterial blood flow is restricted due to extravascular compression, whereas it is greatest during diastole when the intramyocardial vessels are not compressed. Metabolic regulation plays a more significant role than neural regulation in the control of coronary arterial blood flow. Activation of the cardiac sympathetic nerves constricts the coronary resistance vessels, but the associated increase in heart rate and contractile force leads to vasodilation, overriding the direct constrictor effect of sympathetic nerve stimulation. Stimulation of the cardiac branches of the vagus nerves causes slight dilation of the coronary arterioles. There is a strong correlation between the metabolic activity of the heart and coronary arterial blood flow. A decrease in oxygen supply or an increase in oxygen demand appears to trigger the release of vasodilators that reduce coronary arterial resistance. The most likely candidates for mediating this response are KATP channels, NO, H2O2, and adenosine, although CO2, O2, and H+ cannot be ruled out.

The majority of resistance vessels in the skin are under dual control of the sympathetic nervous system and local vasodilator metabolites. However, the AV anastomoses found in the hands, feet, and face are solely under neural control. Skin blood vessels play a significant role in regulating body temperature by constricting to conserve heat and dilating to release heat. They directly and reflexively dilate in response to heat and constrict in response to cold.

In skeletal muscle, blood flow is centrally regulated by sympathetic nerves and locally regulated by the release of vasodilator metabolites. At rest, neural control has a more dominant influence on skeletal muscle blood flow.
Mean arterial pressure varies directly with cardiac output and total peripheral resistance. Arterial pulse pressure varies directly with stroke volume but inversely with arterial compliance.
8.
Blood flow through capillaries is regulated chiefly by contraction of arterioles (resistance vessels). The capillary endothelium is the source of NO and PGI2, which relax vascular smooth muscles.
9.
Water and small solutes move between the vascular and interstitial fluid compartments through capillary pores mainly by diffusion but also by filtration and absorption. Molecules larger than approximately 60 kD are essentially confined to the vascular compartment. Lipid-soluble substances, such as CO2 and O2, pass directly through the lipid membranes of the capillary; the rate of transfer is directly proportional to their lipid solubility. Large molecules can move across the capillary wall in vesicles by pinocytosis. The vesicles are formed from the lipid membrane of the capillaries.
10.
Capillary filtration and absorption are described by Starling’s equation:
Filtration occurs when the algebraic sum of these terms is positive; absorption occurs when it is negative.
11. Fluid and protein that have escaped from blood capillaries enter lymphatic capillaries and are transported via the lymphatic system back to the blood vascular compartment.
12.
Physical factors that influence coronary arterial blood flow are the viscosity of the blood, frictional resistance of the vessel walls, aortic pressure, and extravascular compression of the vessels within the walls of the left ventricle. Left coronary arterial blood flow is restricted during ventricular systole by extravascular compression, and the flow is greatest during diastole, when the intramyocardial vessels are not compressed. Neural regulation of coronary arterial blood flow is much less important than metabolic regulation. Activation of the cardiac sympathetic nerves constricts the coronary resistance vessels. However, the enhanced myocardial metabolism caused by the associated increase in heart rate and contractile force produces vasodilation, which overrides the direct constrictor effect of sympathetic nerve stimulation. Stimulation of the cardiac branches of the vagus nerves causes slight dilation of the coronary arterioles. A striking parallelism exists between metabolic activity of the heart and coronary arterial blood flow. A decrease in O2 supply or an increase in O2 demand apparently releases vasodilators that decrease coronary arterial resistance. Of the known factors (CO2, O2, H+ , K+ , H2O2, adenosine) that can mediate this response, KATP channels, NO, H2O2 and adenosine are the most likely candidates, although CO2, O2, and H+ cannot be ruled out.
13.
Most of the resistance vessels in the skin are under dual control of the sympathetic nervous system and local vasodilator metabolites. The AV anastomoses found in the hands, feet, and face, however, are solely under neural control. The main function of skin blood vessels is to aid in the regulation of body temperature by constricting to conserve heat and by dilating to lose heat. Skin blood vessels dilate directly and reflexively in response to heat, and they constrict directly and reflexively in response to cold.
14.
Blood flow in skeletal muscle is regulated centrally by sympathetic nerves and locally by the release of vasodilator metabolites. In persons at rest, neural
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