Cutaneous Circulation – Special Circulations

by Thad Wilson, PhD

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    We also want to think about the cutaneous circulation. Skin circulation is very important for dissipating heat. So if you're out on a hot day you'll need to vasodilate the skin in order for you to thermoregulate. If you didn't thermoregulate you would overheat, you get heat exhaustion, heat stroke and could die. To look at the control of skin blood flow, however, we have to break apart the different types of skin. Non-glabrous skin is what is hairy skin, skin that has hair on it and we're going to contrast that to glabrous skin which is skin that does not have hair on it such as the palms, the ears, sometimes the nose and those areas are controlled a little bit differently but let's talk about non-glabrous skin first. In resting condition, skin blood flow is fairly low and stable. In response to a cold stress, the sympathetic nervous system is activated and this will cause a vasoconstriction. This vasoconstriction is mediated through alpha 1 and alpha 2 adrenergic receptors. So this is the release of norepinephrine causing these responses. The other neurotransmitter that is important is neuropeptide Y. It is also released by noradrenergic nerve terminals. In response to heat, you will first release vasoconstriction and then you will actively vasodilate the skin. This active vasodilation utilizes acetylcholine meaning that it's related to a cholinergic nerve but it's not solely acetylcholine that mediates the response. Oddly, yet we don't know exactly what that molecule is. It's likely co-released with acetylcholine but we're not sure what it is. The only thing we do know is that it's likely related in some way to nitric oxide. Nitric oxide is a gas that diffuses into smooth muscle and causes it to relax. Now if we think about glabrous skin, remember glabrous...

    About the Lecture

    The lecture Cutaneous Circulation – Special Circulations by Thad Wilson, PhD is from the course Vascular Physiology.

    Author of lecture Cutaneous Circulation – Special Circulations

     Thad Wilson, PhD

    Thad Wilson, PhD

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