How does blushing really work? The moment you're embarassed, your cheeks feel hot and you turn red.?

What's the biology behind it? Can someone describe the step by step process? Also, sometimes when your cheeks feel hot, you think you're red but you look and see you're not. That's interestingHow does blushing really work? The moment you're embarassed, your cheeks feel hot and you turn red.?
';There is evidence that the blushing region is anatomically different in structure. The facial skin, for example, has more capillary loops per square millimeter and generally more vessels per unit volume than other skin areas. In addition, blood vessels of the cheek are wider in diameter, are nearer the surface, and visibility is less diminished by tissue fluid. These specific characteristics of the architecture of the facial vessels led Wilkin in an overview of possible causes of facial flushing to the following conclusion: ';[...] increased capacity and greater visibility can account for the limited distribution of flushing'; (Wilkin. 1988).





Evidence for special vasodilation mechanisms was reported by Mellander and his colleagues (Mellander, Andersson, Afzelius, %26amp; Hellstrand. 1982). They studied buccal segments of the human facial veins in vitro. Unlike veins from other areas of the skin, facial veins responded with an active myogenic contraction to passive stretch and were therefore able to develop an intrinsic basal tone. Additionally Mellander et al. showed that the veins in this specific area were also supplied with beta-adrenoceptors in addition to the common alpha-adrenoceptors. These beta-adrenoceptors could exert a dilator mechanism on the above-described basal tone of the facial cutaneous venous plexus. Mellander and his colleagues propose that this mechanism is involved in emotional blushing. Drummond has partially confirmed this effect by pharmacological blocking experiments (Drummond. 1997). In a number of trials, he blocked both alpha-adrenergic receptors (with phentolamine) and beta-adrenergic receptors (with propranolol introduced transcutaneously by iontophoresis). Blushing was measured at the forehead using a dual channel laser Doppler flowmeter. Subjects were undergraduate students divided into frequent and infrequent blushers according to self-report. Their mean age was 22.9 years, which is especially favorable for assessing blushing, since young subjects are more likely to blush and blush more intensively. The subjects underwent several procedures, one of which was designed to produce blushing. Alpha-adrenergic blockade with phentolamine had no influence on the amount of blushing in frequent or in infrequent blushers, indicating that release of sympathetic vasoconstrictor tone does not substantially influence blushing. This result was expected since vasoconstrictor tone in the facial area is known to be generally low (van der Meer. 1985). Beta-adrenergic blockade with propranolol on the other hand decreased blushing in both frequent and infrequent blushers. However, despite complete blockade, blood flow still increased substantially during the embarrassment and blushing inducing procedure. Additional vasodilator mechanisms must therefore be involved. So far, no specific mechanism has been suggested.';