Circulatory System Flashcards
What does double circulatory system mean?
Blood goes thru the heart twice for each complete circuit of the body
What are the two circuits that get blood pumped thru?
Pulmonary
Systematic
What size is the pulmonary circuit and what is the adv of its pressure?
Relatively small and pumped at low pressure
Allows blood to pass rel slowly thru capillaries in lungs allowing more time for g.e
What does high pressure of systematic circuit ensure?
Higher pressure ensures blood is pumped to all organs in body at pressure sufficient to deliver metabolites and remove waste
Also, pressure maintains blood/tissue fluid balance in each organ
Describe the structure of artery:
Thick wall: outer thin layer of fibrous tissue with thick middle layer of smooth muscle and elastic tissue with inner layer of squamous endothelium
Narrow Lumen
Rounded Shape
What is the blood pressure of the arteries like?
High in pulses
What does elastic tissue in arteries allow?
Allows stretch and recoil as blood pulses out of heart thru arterial syst following contr of ventr muscles
What does elastic tissue recoil help?
Helps push blood along artery maintaining blood pressure
What is the function of muscle tissue in arteries?
Provides support but also can constrict (vasoconstrict)/ dilate (vasodil) prov >/< blood to an organ
What is function of contr of muscle and narrowing of lumen in artery?
Helps maintain bp
What is the blood pressure like in veins?
Low
Descr the str of the veins:
Thin wall- outer layer of fibrous tissues, thin middle layer cont some muscle- v little elastic tissue with an inner layer of squamous endothelium
What is adv of large lumen in veins?
Little res to blood flow- essential as low bp in veins
What are the functions of the valves?
Prev backflow of blood.
How does amount of muscle tissue in veins compare to arteries?
Much less in veins
What is the function of the squamous endothel on inner layer?
Creates smooth surface reducing friction as blood flows thru
Describe the structure of capillaries?
Microscopic vessels with one cell thick walls consisting of squamous endothelium
What is adv of small size of cap?
Allows ext netw of cap, prov lsa for dif of mat (no cell far from a cap)
What is adv of thin wall of cap?
Fac. exch. of mat with surr cells and tissues thru being permeable to water and solutes and provides a short dif dist
Referring to graph descr blood from aorta to arterioles:
Remains at high pr thru aorta and arteries- still close to heart
Pulse effect in bp unmatched by pulse in blood vel due to smoothing effects of elastic and muscle tissue in art wall
What causes red in pressure between aorta and arteries?
As main arteries branch into large no. smaller arterioles increases csa
What is the cause of the reduction in pressure between caps and veins?
Facilitates exchange of mat between blood and surr tissue fluid as blood flows from cap
Why does pressure reduce when blood leaves cap?
Overall csa of bv decrease as cap unite-> venules-> veins
What does the large lumen in each vein ensure?
Ensures friction between blood and wall of vein is reduced to ext blood vel can increase even tho bp is still low
What sep two sides of heart?
Septum
Why are atria rel thin?
B/c removes blood from lungs (LA)/ body (RA) and pumps blood to ventr (directly below them)
Why is LV thicker than RV?
Lungs only few cm from heart so RV doesnt pump as far and with force LV has to pump blood around the body
What is function of atrioventricular valve?
Tricuspid and bicuspid: lie between atria and ventr and prevents backflow of blood into atria when ventr contract
What is function of semilunar (arterial valves)?
Lie at base of aorta and pulm artery and prev backflow of blood from arties to ventricles
What is the funct of the papillary muscles?
Anchor AV valves and they are embedded in ventricle wall
What is the funct of the chordae tendinae?
Link muscle and valves
What are the adaptations of the c.tendinae?
Extremely tough and flexible- not elastic
Ensures when ventr contract ( with high pressure in ventr forcing AV valves shut), prev valves turning inside out which would allow blood to flow back to atria
What is the funct of the semi-lunar valves?
Pocket valves in artery walls only close when bp in arteries less than bp in veins
Descr the function of the aorta:
Major art carrying ox blood out of LV
Art. branch leading from aorta carry blood to all major organs of bod except lungs
Descr function of pulm artery:
Carries deox blood from RV -> Lungs
Descr function of Vena Cava:
Brings deox blood back from body returning blood to RA