Exam 1 Review:  Chapter 19:  Arterial Tree

elastic artery - The descriptive category for the largest of the arteries which are found near or attached to the heart; they have the largest diameters and the thickest walls of any of the blood vessels, but have slightly more elastic fibers and less smooth muscle proportionately than the next smaller muscular arteries; they are also called conducting arteries because the distribute blood to the general regions (head, trunk, limbs) of the body; arteries carry blood away from the heart.

muscular artery - The descriptive category for the middle-sized arteries which are the main branches from the elastic = conducting arteries; they have intermediate diameters and have more smooth muscle and less elastic fibers proportionately than the larger elastic = conducting arteries; they are also called distibuting arteries because the distribute blood to individual organs of the body; arteries carry blood away from the heart.

collateral circulation - Distribution of blood by means of vessels which have anastomoses or established through indirect or subordinate branches when the supply through the main vessel is obstructed; there is only limited collateral circulation in the pulmonary and coronary circulations while the systemic circulation, especially the venous tree, has more.

microcirculation - The flow of blood or lymph through the smallest vessels (the microvasculature where vessels have a diameter of 100 microns or less) of the body, e.g., the arterioles, capillaries, and venules.

metarteriole = thoroughfare channel -Any of the small peripheral blood vessels between the smallest or terminal arterioles and the true capillaries; these vessels consist of a single layer of simple squamous endothelial cells with scattered groups of smooth muscle fibers dispered along their walls; these vessels often provide the most direct route for blood flow through a capillary bed; they play a role in determining how much blood enters a particular capillary bed at a particular time under the direction of the autonomic NS.

precapillary sphincter - The small ring composed of a few smooth muscle cells which encircle the opening to each capillary which branches from an arteriole; contraction of the precapillary sphincter can close the branches off to blood flow; they play a role in regulating the blood pressure of a particular capillary bed and how much blood enters a particular capillary bed at a particular time under the direction of the autonomic NS.

 1.