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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