A&P 2 Ch. 20 Cardiovascular System: Vessels & Circulation

Elastic (conducting) artery

1. largest artery 2. lots of elastic fiber 3. easily expand and recoil 4. Propel blood onward while ventricles relax 5. Maintain blood pressure 6. Aorta is an example

Muscular (distributing) artery

1. medium-sized 2. lots of smooth muscle 3. regulate blood flow to specific regions 4. constrict or dilate

Describe the structure and function of the types of arteries and veins.

3 basic types of arteries: elastic (conducting) artery, muscular (distributing) artery, and arterioles

5. Explain the relationships between vessel diameter, cross-sectional area, blood pressure, and blood velocity.

An increase in blood vessel diameter increases the cross-sectional area, which causes blood velocity and pressure to decrease. A decrease in blood vessel diameter decreases the cross-sectional area, which causes blood velocity and pressure to increase.

4. Define blood flow, blood pressure, and peripheral resistance.

Blood flow: the amount of blood flowing through body, and organs, a tissue, or blood vessel in a given period (mL/min) Blood pressure (BP): the force that blood exerts against a vessel wall; expressed in mm Hg Peripheral resistance: the opposition to flow that blood encounters in vessels away from heart

Compare and contrast the structures (tunics) of arteries and veins, and arterioles and venules

Both arteries and veins have the same three distinct tissue layers Tunica intima: a thin layer composed of a simple squamous epithelium known as endothelium and a small amount of connective tissue. Tunica media: a thicker area composed of variable amounts of smooth muscle and connective tissue.(It is the thickest layer in all but the largest arteries) Tunica external: primarily a layer of connective tissue, although in veins, it also contains some smooth muscle. Arterioles have the same three tunics as the larger vessels, but the thickness of each is greatly diminished. Venule is an extremely small vein. The walls of venules consist of endothelium, a thin middle layer with a few muscle cells and elastic fibers, plus an outer layer of connective tissue fibers that constitute a very thin tunica external.

Compare and contrast the simple and alterative pathways (anastomoses, portal systems) of blood vessels.

Simple pathway: one major artery delivering, and one major vein returning Alternative pathway: venous anastomosis, arterial anastomosis, arteriovenous anastomosis, portal system

Describe what is meant by degree of vascularization.

extent of vessels in a tissue

Predict the significance of slow blood flow in the capillaries.

high cross-sectional area slow blood flow allows better delivery

Arterioles

small vessels that receive blood from the arteries

28. Explain how net filtration pressure across the capillary wall determines movement of fluid across that

wall.