Perfusion Flashcards
Perfusion
the passage of oxygenated capillary blood through body tissues
What does adequate perfusion depend on
normal functioning of respiratory and cardiac functions
What is the command center of perfusion
heart
What is the most influential structure in blood flow regulation
arteries
What make arteries able to contract and dilate
muscular walls
What occurs when the pressure in the arteries/arterioles increases
the resistance against the pumping action of the heart increases
What holds arteries together
tunica adventitia
What differentiates between an artery and a vein
tunica media
Why is the tunica media important in arteries
the smooth muscle is needed to pump oxygenated blood out, dilates and contracts
Parts of an artery from the outside in
Tunica adventitia/externa, tunica media, tunica intima
What is the tunica adventitia/externa made of
connective tissue
What is the tunica media made of
smooth muscle
What is the tunica intima made of
basement membrane and endothelial cells
Endothelium
smooth, continuous surface of endothelial cells that make up the innermost layer of all arteries and the heart
What does the endothelium do
metabolically active tissue that releases substances, reacts to chemical mediators, and responds to blood contents
Metabolic functions of the endothelium (6)
fluid filtration, maintenance of blood vessel tone, hemostasis, angiogenesis, neutrophil chemotaxis, and hormone secretion
What does the endothelium secrete
nitric oxide, endothelin, vascular endothelial growth factor (VEGF), thromboxone A2, prostacyclin, von willebrand factor
What does the nitric oxide do
stimulates blood vessel vasodilation
What does endothelin do
stimulates vessel vasoconstriction
What does vascular endothelial growth factor (VEGF) do
stimulates the growth of new blood vessels (angiogenesis)
What does thromboxane do
activates clotting
What does prostacyclin do
inhibits clotting
What does von willebrand factor do
activates clotting
Why is endothelial injury important
key event in the development of atherosclerosis leading to atherosclerotic plaque formation
Vasoconstriction or vasodilation with endothelial injury
vasoconstriction with an increase in substances at the site –> decreased perfusion
What substances are affected by endothelial injury
WBC to the site of the injury, inhibits release of nitric oxide, increases release of von willebrand factor
