BIO 235 CHAPTER 21
hemodynamics - the forces involved in circulating blood throughout the major blood
vessels/circulatory routes of the body
arteries - carry blood away from the heart to major organs. begin as large elastic
arteries and divide into medium sized muscular arteries that branch out into the various
regions of the body
arterioles - smallest arteries, branched from arteries and turn into capillaries
capillaries - microscopic vessel through which exchanges take place between the blood
and cells of the body
venules - small vessels that gather blood from the capillaries into the veins (branch back
together)
veins - Carry deoxygenated blood back to the heart, merged into larger vessels from
venules
three layers of blood vessels - tunica intima, tunica media, tunica externa
layers of tunica intima - lumen, endothelium, basement membrane, internal elastic
lamina
lumen - the interior or opening of a vessel
endothelium - the innermost layer of the tunica interna, lining the lumen
structure of endothelium - continuous with the endocardial lining of the heart, thin layer
of flattened cells
function of endothelium - physical influence on blood flow (facilitates efficient blood flow
by reducing surface friction, smooth tissue), secretion of chemical mediators that
influence the contractile state of the smooth muscle, assistance with capillary
permeability
structure and function of basement membrane - provides physical support base for the
vessel, allows for stretching and tensing, regulates molecular movement and guides cell
movement during vessel repair, all due to the structure of collagen fibres
internal elastic lamina - External layer of tunica interna, only found in arteries
structure of internal elastic lamina - a thin layer of elastic fibres with windows that give it
a swiss cheese-like appearance
, function of internal elastic lamina - windows allow for diffusion of materials from tunica
interna to the thicker tunica media
tunica media - The middle and thickest layer of tissue of a blood vessel wall, composed
of elastic tissue and smooth muscle cells
function of tunica media - regulate the diameter of the lumen. i.e. expand and contract
the blood vessels in response to changes in blood pressure and tissue demand
external elastic lamina - another layer of elastic fibres separating the tunica media from
the tunica externa
tunica externa (adventitia) - the outermost layer of a blood vessel
structure of tunica externa - elastic fibres and nerves, as well as tiny blood vessels that
supply the tissue of the vessel wall (in the larger blood vessels such as the aorta)
vasoconstriction - a decrease in the diameter of the lumen of a blood vessel
vasodilation - widening of the diameter of the lumen of a blood vessel
when does vasodilation occur? - in response to decrease of sympathetic stimulation,
increase of parasympathetic stimulation, in the presence of certain chemicals such as
lactic acid or nitric oxide, in response to blood pressure.
vasa vasorum - vessels of vessels - the small blood vessels that feed the larger vessels
in the body
compliance - meaning the walls of arteries stretch and expand easily without tearing in
response to increases in blood pressure
elastic arteries - largest arteries in the body
examples of elastic arteries - the two major vessels that exit the heart (aorta and
pulmonary trunk), and the vessels that branch from the aorta including the
brachiocephalic, subclavian, common carotid, common iliac
function of elastic arteries - Propel blood onward while the ventricles are relaxing
elastic lamellae - the well defined internal and external elastic laminae that categorize
the elastic arteries. surround a thick tunica media
pressure resevoir - as elastic arteries stretch the elastic fibres momentarily store
mechanical energy
hemodynamics - the forces involved in circulating blood throughout the major blood
vessels/circulatory routes of the body
arteries - carry blood away from the heart to major organs. begin as large elastic
arteries and divide into medium sized muscular arteries that branch out into the various
regions of the body
arterioles - smallest arteries, branched from arteries and turn into capillaries
capillaries - microscopic vessel through which exchanges take place between the blood
and cells of the body
venules - small vessels that gather blood from the capillaries into the veins (branch back
together)
veins - Carry deoxygenated blood back to the heart, merged into larger vessels from
venules
three layers of blood vessels - tunica intima, tunica media, tunica externa
layers of tunica intima - lumen, endothelium, basement membrane, internal elastic
lamina
lumen - the interior or opening of a vessel
endothelium - the innermost layer of the tunica interna, lining the lumen
structure of endothelium - continuous with the endocardial lining of the heart, thin layer
of flattened cells
function of endothelium - physical influence on blood flow (facilitates efficient blood flow
by reducing surface friction, smooth tissue), secretion of chemical mediators that
influence the contractile state of the smooth muscle, assistance with capillary
permeability
structure and function of basement membrane - provides physical support base for the
vessel, allows for stretching and tensing, regulates molecular movement and guides cell
movement during vessel repair, all due to the structure of collagen fibres
internal elastic lamina - External layer of tunica interna, only found in arteries
structure of internal elastic lamina - a thin layer of elastic fibres with windows that give it
a swiss cheese-like appearance
, function of internal elastic lamina - windows allow for diffusion of materials from tunica
interna to the thicker tunica media
tunica media - The middle and thickest layer of tissue of a blood vessel wall, composed
of elastic tissue and smooth muscle cells
function of tunica media - regulate the diameter of the lumen. i.e. expand and contract
the blood vessels in response to changes in blood pressure and tissue demand
external elastic lamina - another layer of elastic fibres separating the tunica media from
the tunica externa
tunica externa (adventitia) - the outermost layer of a blood vessel
structure of tunica externa - elastic fibres and nerves, as well as tiny blood vessels that
supply the tissue of the vessel wall (in the larger blood vessels such as the aorta)
vasoconstriction - a decrease in the diameter of the lumen of a blood vessel
vasodilation - widening of the diameter of the lumen of a blood vessel
when does vasodilation occur? - in response to decrease of sympathetic stimulation,
increase of parasympathetic stimulation, in the presence of certain chemicals such as
lactic acid or nitric oxide, in response to blood pressure.
vasa vasorum - vessels of vessels - the small blood vessels that feed the larger vessels
in the body
compliance - meaning the walls of arteries stretch and expand easily without tearing in
response to increases in blood pressure
elastic arteries - largest arteries in the body
examples of elastic arteries - the two major vessels that exit the heart (aorta and
pulmonary trunk), and the vessels that branch from the aorta including the
brachiocephalic, subclavian, common carotid, common iliac
function of elastic arteries - Propel blood onward while the ventricles are relaxing
elastic lamellae - the well defined internal and external elastic laminae that categorize
the elastic arteries. surround a thick tunica media
pressure resevoir - as elastic arteries stretch the elastic fibres momentarily store
mechanical energy
