Vessel Types Flashcards
(19 cards)
Artery
Distributes blood to organs. Generally called muscular arteries because of their thick tunica media containing smooth muscle. Direct the blood flow to the organs. A well seen internal elastic lamina and external elastic lamina.
Medium Artery
Distribute blood WITHIN an organ. Controls flow to specific areas. Fewer layers of smooth muscle and elastic laminae are no longer present. Type I collagen in and near the adventitia are evident.
Small Artery
Even fewer smooth muscle layers and a less well defined adventitia.
Arteriole
1-4 Layers of smooth muscle and final artery system. Regulate blood flow to specific capillary beds. Their main function due to their tone and ability to close down and large cross sectional area is resistance vessels. TPR and arterial BP. Adventitia and endothelial present.
Metarteriole
One layer of smooth muscle. Attaches arteriole and capillaries. Regulates local capillary flow.
Capillaries
Gaseous and metabolic exchange. Lumen is just large enough for one RBC to fit. Continuous, fenestrated, and discontinuous capillaries.
Continuous Capillaries
Muscle, brain, thymus, bone, lung, and other tissues. Caveolae and vesicles transport substances. Continuous basal lamina.
Fenestrated Capillary
Continuous basal lamina. Fluid transport like the intestinal vili, choroid plexus, ciliary process of the eye. Glomular capillaries supported by a slightly thicker basal lamina.
Discontinuous Capillaries
Larger gaps and discontinuous membrane. Spleen.
Pericyte
Capillaries contractile and regenerative.
A-V shunts
Bypass the capillary bed by closing of pre-capillary sphincters.
Venule
Similar but larger than a capillary. Exchanging of gas and nutrients. Endothelial cell layer.
Small Vein
Thin media and adventitia.
Medium Vein
Less smooth muscle and no definable elastic laminae than artery counterpart. Also has a larger cross sectional area. Adventitia is the main part and they do have a discernible elastic laminae.
Vein
Accompanies the artery. Adventitia is the dominant layer.
Large Vein
Adventitia is the dominant layer and contains the vasa vasorum
Vena Cava
Longitudinal smooth muscle relaxation allows the vein wall to bulge outwards permitting the vein to contain a larger volume of blood. Storage and volume buffering.
Lymphatics
Similar to capillaries but larger with an incomplete basement membrane to allow greater permeability. Multiple valves. Drain fluid from the interstitial space.
Aorta/Large Artery
Large number of elastic fibers in its tunica media to maintain BP during diastole. Also true of the next largest arteries including brachiocephalic, subclavian, common carotid, and common iliac arteries. Many dark staining elastic fibers in the media. Largest is the media.
