Unit 4 - Vasculature: Overview and Arteries Flashcards
Generally, what are the layers of a blood vessel?
tunica intima/interna, tunica media, tunica adventitia/externa
What are the layers of the tunica intima/interna?
Endothelium and internal elastic membrane
What is contained in the endothelium of the tunica intima/interna?
A basal laminal layer, and a subendothelial layer
What is the subendothelial layer of the endothelial layer of the tunica intima/interna made out of?
collagen and elastic fibers, fibroblasts, and smooth muscle in some vessels
What is the internal elastic made of and what is its functional significance?
it is a sheet of elastin with gaps that permit nutrient diffusion into the tunica media
What is the tunica media made out of?
elastic and smooth muscle fibers with an external elastic membrane
Where do the elastic and smooth muscle fibers of the tunica media receive their nutrients from?
from the tunica interna, and vasa vasorum
What is vaso vasorum?
the blood vessel for a blood vessel
What is the tunica adventiti/externa made out of?
Connective tissue, vaso vasorum, and nervi vasorum
Rate large arteries, medium/small arteries, and arterioles from high to low levels of elastin.
Arteries > medium/small arteries > arterioles
Rate large arteries, medium/small arteries, and arterioles from high to low levels of smooth muscle.
Arterioles > medium/small arteries > arteries (no smooth muscle)
Rate large arteries, medium/small arteries, and arterioles from high to low levels of vascular resistance.
Arterioles > medium/small arteries > arteries
Do arterioles or veins have more muscle cells?
arterioles
Do large veins or venules have more layers of muscle cells?
large veins
What is the composition of the interna layer of elastic arteries?
thicker than other arteries, brick-like endothelial cells, internal elastic membrane has splits into lamellae that may merge with the tunica media
What is the composition of the media layer of elastic arteries?
thickest of the tunics, fenestrated and concentrically arranged elastic laminae
What is the composition of the externa layer of elastic arteries?
Longitudinal/interlaced collagen fibers, few elastic fibers/FBs
What is the functional significance of elastic arteries?
the elasticity of the large arteries allows them to recoil and maintain high pressure during diastole
What is the composition of the interna layer of the muscular arteries?
thin subendothelial layer with a thick internal elastic membrane that has fenestrations
What is the composition of the media layer of the muscular arteries?
thick, mainly smooth muscle and discontinuous external elastic membrane
What is the composition of the externa layer of the muscular arteries?
collagen, fibroblasts, elastic fibers
What is the structural difference between arteries and veins?
Arteries have thicker elastic muscular walls than veins compared to lumen size and veins have thinner walls with valves in the tunica interna, and few muscles cells in the tunica media
What is the functional difference between arteries and veins?
arteries carry oxygenated blood in systemic circulation and veins carry deoxygenated blood in venous circulation The exception is pulmonary circulation - arteries and veins have opposite functions than normal
What is the structure of an arteriole?
endothelium with a subendothelial connective tissue layer and an internal elastic membrane, there is no external elastic membrane, the tunica externa is made of loose connective tissue
What is the function of arterioles?
constrict and dilate to regulate flow they transport blood from arteries to capillaries
What is the structure of venules?
similar to capillaries - the tunica interna is formed by continuous or fenestrated endothelial cells connected by incomplete tight junctions, a basal lamina, and a thin subendothelial layer of longitudinal collagen fibers
What is the functional significance of venules?
the junctions between the endothelial cells are more permeable than those in capillaries and sensitive to leakage
What is this diagram of?
Pulsatile flow in large arteries
What causes the sharp incisura?
It is when the semilunar valve closes due to the backflow ejection of blood out of the aorta
What line indicates the diastolic pressure?
the blue line
What are characteristics of diastolic pressure in arteries and why?
Diastolic pressure is when the pressure in the arteries is low because the ventricles of the heart are refilling
During irregular heart beats, how does the diastolic pressure in arteries change?
the amount of time that is needed for diastolic pressure to drop changes
What line resembles systolic pressure?
the pink horizontal line
What are characteristics of systolic pressure in arteries and why?
Pressure is high because the ventricles are contracting and ejecting blood
What is pulse pressure?
the difference between systolic and diastolic pressure
What factors affect pulse pressure?
stroke volume, arterial compliance, and character of ejection
If volume increases, what hapens to systolic pressure?
it also increases
If arterial compliance increases, what happens to pressure?
it decreases
If you have increased heart rate, what happens to stroke volume?
it decreases
If you have higher resistance, what happens to stroke volume?
it decreases
If you have more venous return than normal, what happens to stroke volume?
it increases
How do you calculate mean arterial pressure?
diastolic + ⅓ (systolic-diastolic)
