innermost layer of a blood vessel, Includes the endothelial lining and an underlying layer of connective tissue containing a variable number of elastic fiber.
middle layer of blood vessels, contains concentric sheets of smooth muscles tissue in a framework of loose connective tissue.
outermost layer of blood vessel, is a connective tissue sheath. In arteries, this layer contains collagen fibers with scattered bands of elastic fibers.
Difference between arteries and veins
Walls of arteries are thicker than veins, Arteries are thick and strong, they retain their circular shape, cut veins tend to collapse, and endothelial lining of an artery cannot contract.
Relaxation of arterial smooth muscles increases the diameter of the lumen in this process.
Vaso constriction and vasodilation affect...
The afterload on the heart, peripheral blood pressure, and capillary blood flow.
or conducting arteries, are large vessels with diameters up to 2.5 cm. They transport large columes of blood AWAY from the heart.
Examples of elastic arteries
Pulmonary trunk, aorta, pulmonary arterie, common carotid arterie, subclavian arteries, and common iliac arteries
also known as medium sized arteries, or distribution arteries, distribute blood to the body's skeletal muscles and internal organs.
Very small, have a poorly defined tunica externa, and the tunica media in the larger arterioles consists of one or two layers of smooth muslce cells.
Permeate most tissues, form intricate networks that surround muscle fibers, radiate through connective tissues, and branch beneath the basal laminae of epithelia. They are the only blood vessels whose walls permit exchange between the blood and the surrouding interstial fluids.
the endothelium is a complete lining. They are located in all tissues except epithelia and cartilage and they permit the diffusion of water, small solutes, and lipid-solubel materials into the surrounding interstitial fluid, but prevent the loss of blood cells and plasma proteins.
Contain windows, or pores that penetrate the endothelial lining. The pores permit rapid exchange of water and solutes as large as small peptides between plasma and interstitial fluid.
Examples of fenestrated capillaries
Choroid plexus of the brain and blood vessels in a cariety of endocrine organs, such as the hypothalamus and the pituitary, pineal, and thyroid gland
also called sinusoidal capillaries, resemble fenestrated capillaries that are flattened and irregulary shaped.
joining of blood vessels, the fusion of two collaterial arteries that supply a capillary bed
is the formation of new blood vessels under the direction of vascular endothelial growth factor
The cycling of contraction and relaxation of smooth muscles that changed blood flow through capillary beds
Medium sized veins
range from 2-9 mm in diameter. In these veins the tunica media is thin and contains relatively few smooth muscle cells.
Include the superior and inferior venae cavae and their tributaries within the abdominopelvic and thoracic cavities.
folds of the tunica intima, that project from the vessel wall and point in the direction of blood flow.
What percent does the heart, arteries, and capillaries in the pulmonary and systemic circuits normally contain?
30-35% of blood volume.
reduces the amount of blood within the venous system, thereby increasing the volume withing the arterial system and capillaries.