Summative Review Flashcards
What does the atrial a-wave correspond to?
atrial systole
occurs when the mitral valve closes
What does the atrial V-wave correspond to?
passive filling of the RA when the tricuspid valve is closed
Differences between exercise and maximal sympathetic stimulation of heart
In exercise, arteries dilate which causes decreased TPR and corresponding decreased afterload
Also, skeletal muscle pumping increases preload in exercise
Similarities between exercise and maximal sympathetic stimulation of heart
Both increase HR and contractility
Both lead to a decrease in ESV due to increased contractility
In sympathetic or exercise does ESV decrease more?
ESV decreases more in sympathetic
Sympathetic = increase TPR = increase afterload
Increase afterload = increase contracility
Increase contracitlity = decrease ESV
Clonidine effects on TPR
clonidine is a alpha 2 agonist
prevents sympathetic simulation so therefore, increases TPR
Which drug norepinephrine or epinephrine produces a larger increase in afterload? Why?
Norepinephrine since it primarily binds B1 and alpha receptors
Epinephrine binds B2 receptors which causes vasodilation
Prazosin and phenoxybenzamine chronotropic / ionotropic effects
Both are alpha antagonists which should cause a decrease in HR and contractility
HOWEVER, the baroreceptor kicks in which causes an increase in HR and contracility
Prazosin and phenoxybenzamine effect on TPR
decrease
How do you calculate the blood pressure needed at heart level to adequately perfuse the brain?
you are going to drop pressure as you go up
so at the heart, you need to add the pressure you will lose along the journey to the pressure you want
P = (needed pressure) + (distance / 13.6)
to calculate pressure lost, divide distance by 13.6 since for every 1 mmHg, you push blood up 13.6 mm
make sure you are doing these calculates in mm
What happens to the vagal response upon standing?
vagal is suppressed because the baroreceptor is doing everything it can to increase HR since SV is decreasing because blood pooling in legs
Difference between calculating systemic vascular resistance and pulmonary resistance?
systemic / coronary: subtract RAP on numerator for anything that passes through systemic circulation / aorta
pulmonary: subtract LAP on numerator for anything that goes through pulmonary circulation
What are the 2 general formulas for calculating MAP?
MAP = CO * TPR
MAP = (1/3)(systole) + (2/3)(diastole)
What are the 2 main pathologies that affect afterload?
HTN and aortic stenosis
As venous compliance increases, what happens to TPR?
TPR decreases
When does the atrial c-wave occur?
before the aortic valve opens
When does ventricular systole end on ECG?
ends after the T-wave
(remember mechanical changes proceed electrical changes)
When arterial BP increases what is the result on aortic valve opening and closing?
opening is delayed and closing is earlier
Why does the atrial pressure c-wave occur?
C-wave occurs as AV opens
When AV opens, there is contraction and the tricuspid valve bulges into the atrium causes a small increase in atrial pressure
What happens if you have immediate AV damage?
you cannot empty the LV
this leads to increased ESV and preload
What happens to ESV and EDV if you dilate the arterioles?
both will be reduced due to less preload
that said, stroke volume should remain the same
What happens to ESV, EDV and stroke volume with dobutamine use?
dobutmaine effects B1
increased contractility = decreased ESV / EDV
stroke volume stays the same despite decreased ESV because of the increase in contracility
What two things increase MSFP?
1) increase in BV
2) decrease in venous compliance
Does mean systemic filling pressure increase during exercise or sympathetic stimulation?
increases during sympathetic stimulation since the arteries are getting squeezed more
actually, says that due to skeletal muscle pumping combined with some sympathetic stimulation, MSFP might actually be slightly higher during exercise
MSFP increases in both!