Cardiovascular [Blood Vessels] Flashcards
Elastic artery function and structure
Smooth the flow of blood leaving the ventricles.
Many thin sheets of elastin in middle tunic.
Muscular artery function, what is flow porportional to?
Distribute blood around the body at high P and heart at med.P. Vasoconstriction / dilation.
Flow = r^4
Muscular artery structure
Inner tunic
Middle tunic with smooth muscle
Outer tunic (adventitia)
Arteriole function and description (minus structure). Degree of constriction determines ____.
Control blood flow to capillary beds. The vessels where the greatest P drop occurs and great R to flow. Thickest relative to size. Degree of constriction determines total peripheral R and therefore mean arterial BP.
Arteriole structure
1-3 layers of circular smooth muscle wrapped around the vessel in the middle tunic.
Capillary function
Thin walls for gas exchange between blood and tissue fluid. Slow blood flow. Leaky - lymphatic picks up. Most of lost plasma recovered through osmosis.
Capillary structure
Diameter for one RBC. Layer of endothelium with BM. No smooth muscle or CT.
Venule function
Low pressure vessels which drain capillary beds. WBC for infection.
Venule structure
Endothelium + CT. Larger ones have a single layer of smooth muscle.
Veins function (
Thin walled low pressure. Blood to atrium except portal veins. Stretch easy.
Veins structure
Similar to muscular artery but thinner (less muscle and CT). Larger veins have valves (eg. Bicuspid) to stop gravity pulling blood down.
Coronary arteries structure and function (brief)
Muscular arteries that supply myocardium, keeping the heart alive.
Coronary arteries problems
Can be narrowed by atheroma. During exercise the myocardium that this artery supplied will be low on O2 (ischemia) causing chest pain (angina). Sever ischemia results in death (infarction) of myocardium. Sometimes artery-artery junctions widen so another artery can supply it.
What drains deO2 blood from the myocardium? Where is it returned?
Cardiac veins and return to right atrium.
Where do the cardiac veins drain
RA
