Cardiovascular: Arteries and Veins L2 Flashcards
Name some major arteries in the lower limb.
Common iliac artery, Femoral artery, Posterior tibial artery.
Name some major veins in the lower limb.
Posterior Tibial Vein, Femoral vein, Great saphenous vein (superficial), Common iliac vein.
Name some major veins in the upper parts of the body back towards the heart.
Superior vena cava, brachiocephalic veins, Azygos veins, Internal Jugular vein, External Jugular Vein, Left and Right Subclavian vein.
What are the three layers of blood vessel.
Tunica Intima, Tunica Media, Tunica Adventitia.
What is the Tunica Intima made of?
The innermost part is called the endothelium, and consists of a simple squamous (flattened) epithelium. The endothelium lines all blood vessels and the heart. Below the lumen is the supporting tissue called Subendothelium made up of loose fibrous connective tissue. The final part is the Internal Elastic Lamina, a condensed sheet of elastic tissue (larger in arteries than in veins).
What is the Tunica Media made of?
Consists of smooth muscle with varying about of connective tissue, mainly elastin and collagen. Width of media depends on diameter of artery and blood pressure. External elastic lamina is present in larger arteries between tunica media and tunica adventitia, but not as prominant as IEL.
What is the Tunica Adventitia made of?
Loose FCT with high amounts of collagen and varying amounts of elastin. In larger arteries, Vasa Vasorum is found (network of small blood vessels for the blood vessel as it is also an organ and requires nutrients, and the Adventitia is far away from the lumen so too far away for diffusion to occur). May also contain lymphatics and nerve fibers. (Thickest layer in a vein wall).
Why is there only sometimes elastic lamina in the blood vessel walls?
Pressure is very high in aorta and decreases as it goes through the rest of the body. Elastic Lamina squeezes lumen of blood vessel to help close valve and help propel blood further along arteries like a passive pump. Smaller arteries are less about pumping and more about deciding final destination, so diameter of lumen changes to help redirect flow of blood.
What is the function of an arteriole?
Resistance vessels of the circulation - determine blood pressure.
Explain what are Venules?
The first part of the venous drainage network. Smallest veins, straight after the capillary exchange. Very thin walled because pressure is very low. Has monocuspid valve. Still has endothelium like the rest of the circulatory system.
How much pressure is in the veins? What does this mean about the amount of blood it can store? Do veins have valves?
Blood pressure is much lower than the arterial system. Starts with venules and ends with vena cavae. Because of lower pressure, stores a large part of the total volume of blood in the body (veins are capacitance vessels - hold extra blood that can move to arteries in an emergency). Many veins have valves to ensure unidirectional flow.
Compare the composition of a vein’s wall to arteries’ wall.
They both have the same named three layered walls but have a difference compositions. The vein intima is very thin and the lumen is large. The IEL is either absent or very thin. Valves are formed from the intima. The media is a lot thinner than in arteries, contains few layers of smooth muscle. The adventitia is usually the thickest layer in vein wall because of the capacitance role.
