Vessel Types

Question 1

Artery

Answer 1

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.

Question 2

Medium Artery

Answer 2

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.

Question 3

Small Artery

Answer 3

Even fewer smooth muscle layers and a less well defined adventitia.

Question 4

Arteriole

Answer 4

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.

Question 5

Metarteriole

Answer 5

One layer of smooth muscle. Attaches arteriole and capillaries. Regulates local capillary flow.

Question 6

Capillaries

Answer 6

Gaseous and metabolic exchange. Lumen is just large enough for one RBC to fit. Continuous, fenestrated, and discontinuous capillaries.

Question 7

Continuous Capillaries

Answer 7

Muscle, brain, thymus, bone, lung, and other tissues. Caveolae and vesicles transport substances. Continuous basal lamina.

Question 8

Fenestrated Capillary

Answer 8

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.

Question 9

Discontinuous Capillaries

Answer 9

Larger gaps and discontinuous membrane. Spleen.

Question 10

Pericyte

Answer 10

Capillaries contractile and regenerative.

Question 11

A-V shunts

Answer 11

Bypass the capillary bed by closing of pre-capillary sphincters.

Question 12

Venule

Answer 12

Similar but larger than a capillary. Exchanging of gas and nutrients. Endothelial cell layer.

Question 13

Small Vein

Answer 13

Thin media and adventitia.

Question 14

Medium Vein

Answer 14

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.

Question 15

Vein

Answer 15

Accompanies the artery. Adventitia is the dominant layer.

Question 16

Large Vein

Answer 16

Adventitia is the dominant layer and contains the vasa vasorum

Question 17

Vena Cava

Answer 17

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.

Question 18

Lymphatics

Answer 18

Similar to capillaries but larger with an incomplete basement membrane to allow greater permeability. Multiple valves. Drain fluid from the interstitial space.

Question 19

Aorta/Large Artery

Answer 19

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.