MCM Final - Skin Physiology Flashcards
glomus bodies
function to direct blood way from skin surface when exposed to cole temperature
- way to prevent heat loss - also allows for max heat disappation
apical skin
present on nose, lips, ears, hands, feet (more distal)
high surface are to volume ratio
-favors heat loss
has glomus bodies
under SNS control (tone high under normal conditions)
non-apical skin
lacks glomus bodies
cholinergic - vasodilation
adrenergic - vasoconstriction
kallinrein and bradykinin
vasoactive compounds relax vascular smooth muscle
cutaneous blood supply
blood to dermis only (epidermis is avascular)
increased core temp - passive vasodilation - heath loss
decreased core temp - increase SNS tone vasoconstriction - conserve heat
white reaction
blanching of skin when stroked with sharp instrument
expulsion of blood bc of microvascular smooth muscle contraction
-empties capillary loop
lasts 15-60 seconds
triple response
with more forceful pointed instrument
red reaction > flare reaction > wheal reaction
red reaction
increased redness due to vasodilator release from disturbed cells
flare reaction
red line from red reaction spreads out after several seconds
dilation of arterioles from axon reflex (local neural response to sensory receptor stimuli)
wheal reaction
line of injury with local edema
due to increased permeability in response to HISTAMINE
apocrine sweat glands
empty into hair follicles
active at puberty
produce BO
no role in body temp reg
merocrine sweat glands
aka eccrine
main role is body temp regulation
acetylcholine triggers sweat secretion
Na/K/Cl cotransporter mediates excretion of NaCl, urea, lactate > water follows
Na and Cl are reabsorbed resulting in HYPOTONIC SWEAT
CFTR
cystic fibrosis transmembrane receptor
defects lead to inability to reabsorb Na and Cl of salt
excess loss of these ions
-bummer dude!
intrinsic aging
independent of sun exposure
decreased epidermal thickness
decreased melanocytes
decreased immune surveillence
ECM decays
photoaging
due to sun exposure
causes coarse wrinkles
shivering
temp regulation in cold
-can increase heat production by 400% wowza!
passive heat loss
radiation, convection, evaporation
conduction
heat transfer between skin and solid environmental objects
radiation
heat loss to air
convection
wind carries heat away from body
peripheral sensory receptors for heat
all over skin surface
both warm and cold sensors
pathway from CNT via thalamic pathway to cerebral cortex
central receptors for heat sensation
near preoptic and anterior hypothalamus
sense internal (core) temperature
important in regulating during exercise
efferent signals from the CNS in heat regulation
blood flow from core to skin surface
SNS adjusts skin blood blow
sweat glands (eccrine) activated by SNS (more evap cooling)
skeletal muscles shiver - involuntary contractions/relaxations
-increase body temp
SNS effect on blood flow to skin
stronger affect on sweating (not so much on blood flow to skin)
kinins
cause dilation of arterioles, constriction venules
increased capillary pressure and permeability
cytokines and thermoregulation
released by macrophages and lymphocytes in response to infection and inflammation
release prostaglandins that interact with 3rd ventricle of brain
sweating inhibited and shivering occurs
-increase temp to enhance immune response
mechanoreceptors in skin
pacinian, meissners, ruffinis, merkels, krauses
