CH15 Pt3 Flashcards
Decreased Heart rate leads to:
Decreased Cardiac Output (lower Q)
Decreased Cardiac Output (lower Q) leads to:
Decreased BP
Increase in TPR means
An increase in BP
Sources of Peripheral Resistance (3)
Vessel diameter (increase diameter= increase resistance to flow)
Blood Viscosity (increase viscosity= increase resistance)
Blood Vessel Length (increase length= increase resistance)
Poiseuilles Law
Expresses relationship among pressure differential, resistance, and flow
Atherosclerosis
Narrowing of the arteries
-decreased diameter due to build up of plaque
-affects resistance, BP=higher
Arteriosclerosis
Hardening of the arteries
-less elasticity to absorb the force of pulsatile flow
-if hardened cannot distend to absorb force, so force bounces off
Blood flows because of
A pressure gradient (aka pressure differential)
BP is higher in aorta and arteries, lowest in veins and right atrium
Coronary Circulation
Heart pumps to the entire body, but as it is a muscle it needs its own blood supply
Myocardial blood flow= 250ml/ min (5% of Q)
Coronary arteries
Branch off the aorta, just past aortic valves
2 (R and L) -each branch into 2 more
-occurs mostly during diastole
Coronary Veins
Return blood to the right atrium
-coronary sinus (LV) and anterior cardiac vein (RV)
Coronary Artery Blockage leads to what?
Myocardial infarction (heart attack)
O2 consumption equation
a-vO2 diff X Q
Myocardium consumes how much oxygen
70-80% of oxygen from circulated blood
-heart pulls a lot because it never rests, beating faster = more oxygen needed
During exercise, coronary blood flow increases how much?
4-6 times due to increased heart rate, force of contraction, and vasodilation
