Microcirculation Flashcards
List the 4 starling forces components when related to capillaries
hydrostatic pressure within capillary and interstitial hp outside
Oncotic pressure within capillary & interstitial osmotic pressure
Under normal conditions which have more and less pressure inside and outside the capillary
Both interstitial hydrostatic pressure & osmotic pressure are lower than inside capillary.
In terms of arterioles & veins- when does filtration dominate and absorption dominate?
Filtration in arterioles & absorption in venous side
Describe a few of the lymphatic systems role in circulation
absorp the 10% interstitial fluid not reabsorbed by capillaries, move it throughout the body. Lymph nodes contain immune cells that respond to infection
Whats the most common cause of lymphedema world wide?
Filariasis (parasitic roundworm); others include surgery & breast cancer
what are some examples of things causing swelling/edema/erythema in regards to the capillaries
epinephrine, and NITRIC OXIDE (vasodilator) histamine/bradykinins may be released by trauma, infections causing dilation of arterioles/venules. This may lead to leaky capillaries
This hormone/vasoactive substance can cause vascular spasms, implicated as part of pathology in migraines
Serotonin
prostaglandins
cause vasoconstriction or vasodilation
This is a endothelial generated vasodilator
nitric oxide
Define/Describe autoregulation
the ability to maintain a relatively constant flow on a wide range of changing arterial pressure (50-150)
which organs in particular use autoregulation
heart, kidneys, and the brain
define hypoxic pulmonary vasoconstriction and why it is different than the “norm”
when lungs are experiencing low O2 there vascular beds constrict vs. the rest of the vascular beds in body would rather dilate.
Can you list the two mechanisms for autoregulation
myogenic and metabolic hypothesis
what is the myogenic hypothesis in reference to explaining autoregulation
when vascular smooth muscle is stretched, it contracts
whats the metabolic hypothesis in reference to autoregulation
accumulation of metabolic byproducts such as CO2, H+, lactate, cause vasodilation of arterioles
This would be termed for right ventricle heart failure & it also gives indication as to where the problem would be
core pulmonic (in lungs)
what causes leaky capillaries
histamine, which acts to dilate vascular beds
What’s the difference between gas exchange in normal capillaries throughout the body vs. alveolar gas exchange in lungs when it comes to hypoxic conditions
Capillaries throughout the bodies dilate
vs.
Lungs/alveoli constrict
explain why hypoxic pulmonary vasoconstriction is an exception to all other vascular beds
Normally capillaries want to dilate and increase O2 to the tissues, but in lungs= low O2 wants to be avoided so that blood shunts that area to get a better gas exchange elsewhere
