A&P2 lecture 2 part 1 Cardiovascular system

winniesmith1's version from 2017-03-13 11:55

Section 1

Question Answer
ArteriesCarry blood away from heart
ArteriolesSmallest branches of arteries
CapillariesSmallest blood vessels, location of exchange between blood and interstitial fluid
VenulesCollect blood from capillaries
VeinsReturn blood to heart

Section 2

Question Answer
3 basic layers (or tunics) of arteries and veinsTunica intima, Tunica media, Tunica, externa
Structure of tunica intima- Inner lining in direct contact with blood à Endothelium continuous with endocardial lining of heart à Active role in vessel-related activities
EndotheliumMono layer of cells that line all blood vessels à Releases vasoactive substances
How does the endothelium maintain vascular homeostsisRegulation: vascular tone (blood flow and blood pressure) -maintains vessel integrity
Structure of tunica media- Muscular and connective tissue layer -Greatest variation among vessel types - Smooth muscle regulates diameter of lumen
Structure of tunica externa (adventitia)Elastic and collagen fibers -Vasa vasorum -Helps anchor vessel to surrounding tissue

Section 3

Question Answer
What is the general appearance of arteries-round in shape - thick walls -narrow lumen
What is the general appearance of veins-flattened in shape -thin walls -wide lumen
What are arteries comprised of Endothelial cells -Smooth muscle cells (media) muscular > elastic arteries -Connective tissue: ‚ Elastin: allows some stretch and ‘springiness’ due to pressure ‚ Collagen: limits degree of stretch
Describe elastic arteries -Largest arteries (diameter of aorta)-High elastin content in tunica media -Also known as conducting arteries (distribute blood to medium-sized arteries).
Describe muscular arteriesExample: femoral artery (1cm to 0.3cm). Tunica media contains more smooth muscle and fewer elastic fibers than elastic arteries ƒ Walls relatively thick ƒ Capable of great vasoconstriction/ vasodilatation to adjust rate of blood flow ƒ Also called distributing arteries.
What are anastomosisjoining of two vessels
What are arterial anastomoses-Union of the branches of 2 or more arteries supplying the same body region -Provides alternate routes ‚ Collateral circulation  Coronary circulation  Around joints
What is the function of elastic arteriesFunction as pressure reservoir >Dampening effect >Help propel blood forward while ventricles relaxing. ƒ This process provides a steady flow of blood throughout the cardiac cycle -aids in distribution of blood to medium-sized arteries.

Section 4

Question Answer
What are arterioles Also known as resistance vessels. Abundant microscopic vessels. 2-3 layers of SMCs in tunica media. No elastin in tunica media.
How is blood regulated in arterioles Sympathetic innervation and local chemical mediators can alter diameter and thus regulate blood flow and resistance.
Why are arterioles also known as resistance vesselsOpposition to blood flow. Play very important role in blood pressure regulation
What are metarterioles Short vessels that link arterioles and capillaries
What in metaterioles monitors blood flow into capillariesPrecapillary sphincter
What are arteriovenous anastamosesJoining of arteriole and venule. Bypasses capillaries - throughfare channel