QBank Cards Flashcards
Which vessels have the most effective oxygen extraction in the body?
The coronary arteries. Therefore, the coronary sinus has the lowest oxygen content of any vessel.
What heart sound is consistent with HF? How can it be accentuated?
S3, listening at end expiration in the lateral decubitus position when heart is closest to the chest wall due to dec lung volume
What are the holosystolic murmurs? Which one is heard at the lower left border and increases with inspiration?
Tricuspid regurg, mitral regurg, VSD
- LLSB is tricuspid.
- Inspiration causes inc venous return to R heart > L heart.
What’s the pathophys of PE?
Hypoperfusion of lung parenchyma causes hypoxemia which stimulates respiration -> hyperventilation and respiratory alkalosis. Inc pH, reduced PaCO2, low PO2
What effect does phenylephrine have on TPR?
It increases sympathetic tone, increasing TPR (both CO and venous return are decreased)
What effect does an AV fistula have TPR?
It decreases TPR acutely. Chronically, the SNS and kidney will compensate and cause mean systemic pressure.
What effect does anaphylaxis have on venous return?
Widespread venous and arteriolar dilatation with fluid third spacing, drops venous return
What murmur causes bounding peripheral pulses and carotid pulsations with head-bobbing?
Aortic regurg: large pulse pressure causes abrupt dissenting and quick collapse
- de Musset sign: head bobbing due to momentum transfer from head to neck
What is the effect of verapamil?
Calcium channels actually contribute to the latter part of diastolic depolarization. By blocking them in the SA and AV node, depolarization is slowed.
It also decreased the amt of Ca available in cardiomyocytes
What effect does nitroprusside have on the pressure volume loop?
Nitroprusside is a short-acting vasodilator of both arteries and veins. It decreases preload and after load.
What happens to systemic vascular resistance during exercise?
Overall, there is a decrease because even though there’s contraction of arterioles in all tissues except muscles, there is local vasodilation in muscles from adenosine, K+, ATP, CO2, and lactate. Blood flow to systemic organs doesn’t change.
What is the effect of carotid sinus massage?
It increases the baroreceptor firing rate causing increased parasympathetic discharge to slow HR by slowing conduction at the AV node.
What is the order of cardiac tissue velocity?
Fastest first: Purkinje system (2.2 m/sec), atrial muscle (1.1), ventricular muscle (0.3), and AV node (0.5)
What’s the compensatory response to CHF? How does it actually negatively affect the heart?
CHF causes decreased CO, which is detected as low BP.
-increases sympathetic activity
-stimulation of RAAS
-release of ADH
Excessive vasoconstriction increases after load and reduces CO, fluid retention is caused by dec renal perfusion. Renin and angiotensin also cause fluid retention leading to peripheral edema and pulmonary congestion. This all causes cardiac remodeling
What is the effect of adenosine on the cardiac pacemaker action potential?
It activates K+ channels and prolongs K+ flow, causing a longer negative potential and it inhibits L-type Ca2+ channels making it longer to reach threshold. Overall, HR is decrease
