Cutaneous circulation

DR NILESH KATE
MBBS,MD
ASSOCIATE PROF
DEPT. OF PHYSIOLOGY
CUTANEOUS
CIRCULATION

OBJECTIVES
Cutaneous circulation.
 Cutaneous blood flow- characteristics
features.
 Regulation of Cutaneous blood flow
 Cutaneous vascular response
Thursday, March 31, 2016

CUTANEOUS BLOOD VESSELS.
 Cutaneous arterioles –
dense network just under
dermis.
 Meta arteriole – high
resistance conduits
between arterioles &
capillaries.
 Cutaneous capillaries –
provide larger surface area
for heat exchange.

CUTANEOUS BLOOD VESSELS.
 Venules – extensive sub
papillary venous plexus
 Hold large quantity of blood
 Important role in maintaining
body temperature.
 Arteriovenous anastomosis
– in distal parts of
extremities (hands, feet,
nose, lips & ear lobules)
 Wide, low resistance, serves as
shunt
 Important in body temperature.

CUTANEOUS BLOOD FLOW
CHARACTERISTIC FEATURES.
 Main function.
 Resting blood flow.
 Exposure
 Regional variations
 Blood flow & skin
colour.

MAIN FUNCTION.
 To help in the
Regulation of body
Temperature.
 For Nutritive function –
skin need very less
blood.

RESTING BLOOD FLOW.
 When the person is at
thermal equilibrium
with the environment at
270
c
 10-15ml/min/100 gm
of skin tissue.

EXPOSURE
 To Cold –
 Minimum sweating
 Flow decreases to 1/10th
of normal.
(1ml/min/100gm)
 To Heat –
 Maximum sweating
 Flow increases to 10
times (100-
150ml/min/100gm)

REGIONAL VARIATIONS
 Due to A-V
anastomosis in
certain areas as hands,
feet, nose & ear
lobules.
 During heat stress A-V
anastomosis blood
flow increases
(75ml/min/100gm)

BLOOD FLOW & SKIN COLOUR.
 Basically its due to
pigment present
(Melanin)
 But skin colour also
affected by
 Amount of blood
 Degree of
oxygenation.

REGULATION OF CUANEOUS
BLOOD FLOW
 Skin – very less
metabolic activity.
 O2 consumption –
0.3ml/min/100gm.
 Regulation is mainly by
Nervous Control than
Metabolic Control.

NERVE SUPPLY OF
CUTANEOUS VESSELS
 Sympathetic Vaso-
constrictor
 At rest Cutaneous
vessels have
sympathetic
constrictor discharge
 Its more marked on
A-V anastomosis than
other vessels.

NERVE SUPPLY OF
CUTANEOUS VESSELS
 Parasympathetic
Vasodilator – DO not
supply Cutaneous vessels.
 Vasodilation due to –
 Reduced sympathetic effect.
 Local Bradykinin in sweat
glands.
 Other local vasodilators.

NEURAL CONTROL
MECHANISMS
 Hypothalamic
Control Mechanism.
 Baroreceptor
mediated reflex.
 Cortical control
mechanism.

HYPOTHALAMIC CONTROL
MECHANISM.
 Temperature
Regulation centre of
Hypothalamus
mediate
thermoregulation by
increase & decrease of
sympathetic discharge
to Cutaneous vessels.

MECHANISM.
 Under resting condition.
–
 Person at rest with
thermal equilibrium at
270
c – sympathetic
vasoconstrictor has
mild tonic discharge
 Keep A-V anastomosis
closed.

MECHANISM.
 During exposure to
Heat Stress –
decreases
 A-V anastomosis,
cutaneous vessels
dilates.

MECHANISM.
 Sweat glands
activated due to
cholinergic discharge –
local release of
Bradykinin – increases
blood flow to skin.
(150ml/min/100gm)
 Heat is dissipated by
radiation, evaporation
& conduction.

MECHANISM.
 During exposure to
cold stress – Increase
– cutaneous
Vasoconstriction.
 Total blood flow
Decreases
1ml/min/100gm.
 Leads to heat
conservation.

BARORECEPTOR MEDIATED
REFLEX.
 During circulatory stress
as exercise, Hamorrhage
 Causes vasoconstriction
 Do compensatory
mechanism to divert
blood.

CORTICAL CONTROL
MECHANISM.
 Through Cortico-
Hypothalamic
pathway.
 Corticohypothalamic
centers
 Thoracolumbar
sympathetic cell
bodies
 Skin vessels.

CORTICAL CONTROL
MECHANISM.
 Blanching of skin –
during fear due to
vasoconstriction
through cortical
mechanism.
 Phenomenon of
blushing – during
embarrassment -
corticohypothalamic
control discharge of
sympathetic
cholinergic fibres to
sweat glands
 Bradykinin release
 Vasodilation.

CUTANEOUS VASCULAR
RESPONSE.
 White reaction
 Triple response.
 Axon reflex.
 Reactive hyperemia.
 Cold vasodilatation.
 Cold vasoconstriction.

WHITE REACTION
 When pointed object is
stroked over a skin –
Pale strike line appears
 Cause – contraction of
precapillary sphincters &
blood drains out of
capillaries & small veins.
 Appears in 15 sec.

TRIPLE RESPONSE.
 When skin stroke
more firmly with
pointed objects
 3 parts response
occurs
 Red reaction
 Flare
 Wheal

TRIPLE RESPONSE
RED REACTION FLARE WHEAL
TIME 10 SEC AFTER A FEW MIN AT LAST
APPEARS RED LINE DIFFUSELY
SPREADING
IRREGULAR
OUTLINE REDNESS.
SWEALLING &
LOCALISED
OEDEMA.
CAUSE Dilatation of
precapillary
sphincters
Dilatation of
arterioles &
precapillary
sphincters
Increased capillary
permeability with
extravasations of
fluid.
Control No neural control
Local release of
Bradykinin.
Neural control Local release of
histamine &
histamine like
substances by mast
cells.

AXON REFLEX.
 Definitions:
1. a response elicited by
peripheral nerve stimulation;
attributed to impulses traveling
proximally from the stimulation
site along motor axons,
encountering a branch point, and
then passing distally down the
other branch to activate local
arterioles (to cause vasodilation)
or muscle (to cause contractions).

DERMATOGRAPHIA
 Striking triple response
that occurs as an
unusual reaction.
 Anything drawn on
skin causes.
 Due to excessive
release of Histamine.

REACTIVE HYPEREMIA.
 Phenomenon by vessel
control blood flow to the
organ after ischemia due to
occlusion.
 Cause – local Hypoxia causes
vasodilatation of arterioles &
precapillary sphincters
 So blood flow exceed the
control level when occlusion
is removed.

COLD VASODILATATION.
 Exposure to Cold
 Cutaneous vasoconstriction
due to hypothalamic
mechanism.
 But prolonged & severe
vasoconstriction – Frost
bite.

COLD VASOCONSTRICTION.
 Exposure to cold
 Cutaneous
vasoconstriction due
to hypothalamic
mechanism.

Thank you.

Cutaneous circulation

More Related Content

What's hot (20)

Similar to Cutaneous circulation (20)

More from Dr Nilesh Kate (20)

Recently uploaded (20)

Cutaneous circulation