Integration of Cardiac Function Flashcards
In terms of the sympathetic system what is the; neurotransmitter, receptor, second messenger, functional results?
Norepinephrine. B1 receptors pacemakers and myocytes. Increase in cAMP. Tachycardia; increased contractility.
In terms of the parasympathetic system what is the; neurotransmitter, receptor, second messenger, functional results?
Acetylcholine, M2 (pacemakers; minor myocyte effect). Decrease cAMP. Bradycardia; decreased contractility.
The relationship between cardiac output and oxygen consumption is ___________
Linear or proportional
What is cardiac index (CI)?
It is the attempt to normalize cardiac output to individuals of different sizes since CO increases in people of larger mass. CI = CO/ body surface area.
Does arteriolar vasoconstriction or vasodilation change mean systemic filling pressure (MSFP)?
No it does not because the blood volume has not changed
What happens to peripheral venous pressure and venous return with arteriolar vasoconstriction?
Arteriolar vasoconstriction decreases peripheral venous pressure, resulting in decreased venous return at any given RAP
What happens to peripheral venous pressure and venous return with arteriolar vasodilation?
Arteriolar vasodilation increases peripheral venous pressure, resulting in increased venous return at any given RAP.
What happens to MAP during exercise?
It may have a transient decrease but it typically increases during exercise due to an overwhelming amount of venous return from active muscle pumping and venoconstriction.
In terms of phases of the AP’s in cardiac muscle what does the QRS, ST segment, and T wave correspond to?
QRS - upstroke, Phase 0
ST segment- plateau phase, phase 2
T - ventricular repolarization, phase 3
What is the first heart sound? What about the second?
Closure of AV valves - lub (mitral). Closure of the aortic and pulmonic valves - dub (aortic).
Describe the relationships of the P wave R wave and T wave with cardiac events;
P wave - precedes atrial contraction
R wave - coincides with onset of ventricular contraction
T wave - coincides with onset of ventricular contraction
What is the area inside of a pressure volume loop equal too? What is the area under the bottom of the loop? What is the bottom area + the inside equal to?
Net work done by the heart. Wore done by blood on the heart. The total is all of the work done by the heart.
What happens to SV when atrial filling pressure is increased?
It impedes venous return and thus decreases EDV and SV.
What happens to SV when ventricular filling time is increased?
There is an increase in EDV and SV. Frank-Starling effect.
What happens to SV when ventricular compliance is increased?
EDV is increased and SV increases. Note however that there is a limit to this. Too compliant of a heart leads to cardiomyopathy and is bad.
