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Cutaneous (Skin)circulation
• Dr. Chhaya Saraf
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• Well innervated anastomoticconnections between arterioles &venules specially hands & ners
• !ary with thermoreulation
• "eat stress mainly increases blood#ow throuh $ %! anastomoses ofhands & feet
• ow metabolism
Characteristics
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• Subdermal capillaries & venousple'uses are special reservoirs
•
$lterations in blood #ow can beobserved visually
• hick muscular layer
•
ich nerve supply• *ainly under S+S control
Characteristics,.
" -
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"eat -'c ane n t eSkin
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+ervous control• +oradreneric nerves circulatin epinephrine &
nor epinephrine / !C• !D is due to
– eduction in !C activity
– ocal bradykinin in sweat lands
–
ocal !D metabolites• !C activity is modied by
–"ypothalamic response to temperaturevariation
–Stimulation by temperature receptors throuhlateral spinothalamic tract
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enera responses o orchanes in skin
• 1iery red color in reactive hyperemia /
– e establishment of circulationafter a period of occlusion
– "ypo'ia dilates arterioles
•
2ale 3cold skin / $rterioles areconstricted in shock
• Warm red skin / 4oth are dilated
• udy comple'ion in cold / !D
• -motional factors viacorticohypothalamic (S+S) bersproduces – 4lanchin of skin e.. pale with fear
– 4lushin by aner 3 embarrassment
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riple response• Skin is stroked with blunt ob5ect
–
White reaction / Constriction of precapillary sphincter• Skin stroked more rmly with pointed ob5ect
– ed reaction / redness at the site appears in
about 67 second due to capillary dilation.
–Wheal / local edema due to increased
permeability of capillaries. –1lare / redness spread out from in5ury due to arteriolar dilation
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mechanism
• Red reaction
• Dilatation of precapillary sphincter due to direct response of
capillaries to pressure
• No role of nerves so no effect of anesthesia
• Wheal
• Increased capillary permeability by histamine / sub.P
• Increased capillary pressure due to dilatation of precapillary
sphincter
• Flare –
• Dilatation of arteriole, precapillary sphincters by aon refle
• Increased local blood flo! increases local temperature
• "bolished by local anesthesia
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Axon
reex
1lare isdue toantidromic
conductioninsensorynervebranches
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Study material
Guyton Chapter !"Ganong #$st edition chap% "#
hanks
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