Comparative Anatomy of Blood Vessels

From heart to arteries to arterioles to capillaries to venules to veins and back to heart

When blood flows through two seperate capillary networks before returning to the heart

The joining of two or more blood vessels in the same body region

Allows blood to flow from artery to vein

In ears, toes and fingers
-prone to frostbite when exposed to extreme cold

Provides different routes for blood to reach capillaries

Provides different routes for blood to drain from organs

Carry blood away from the heart
-because they carry oxygen rich blood they are red

-tunica externa: composed of loose CT

-tunica media: composed of smooth muscle, elastic fibers, and collagen fibers

-----innervation: sympathetic motor nerves stimulate smooth muscle

-tunica intima: lining of squamous endothelium attached to basement membrane underlying fibrous CT

Size

-conducting (elastic) arteries: are large and tunica media contains numerous elastic fibers (pulmonary trunk and aorta) *Help pump blood through systemic circulation while ventricles are relaxed

-distributing (muscular) arteries: are smaller than conducting arteries and have more smooth muscle (brachial and femoral artery) *Adjust rate of blood flow

-resistance (small) arteries: contain arterioles
*metarterioles are short vessels that link arterioles to capillary networks

Inhibits coagulation

Allow substances to freely move in and out of blood

Can replace damaged cells and also provide cells that will contribute to new blood vessels

Microscopic blood vessels where gases, nutrients, and wastes are exchanged between blood and tissue cells