Cardiovascular System Flashcards Preview

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Flashcards in Cardiovascular System Deck (30):
1

which circulation usually has more resistance, pulmonary or arterial

arterial circulation

2

Normal MAP?

70-100

3

the low resistance in the pulmonary circuit means what for the arterial and vensus pressures in there

only a small difference is needed between the two to maintain blood flow

4

most coronary venous bloods drains into where

coronary sinus by the right atrium

5

the right and left coronary arteries that supply blood to the heart arise from where

aortic root

6

what part of the heart is the most susceptible to ischemia and why

the Subendocardium, because contraction force is the highest near the endocardium, compressing the coronary vessels to supply the heart with blood

7

why is cardiac venous blood the most deoxygenated then any other tissue

because the myocardium extracts 60-75% of the o2 in blood that comes too it

8

increased 02 to the heart can only be achieved how

by increasing coronary blood flow

9

what are the two most important factors in in coronary blood flow autoreguliton

Adenosine and Nitrix Oxide

10

Adenosine is a product of?

ATP

11

what is the major regulator of flow-mediated vasodilation in large arteries and pre-arteriolar vessels

Nitric Oxide

12

What works within vascular smooth muscles via soluble guanylate cyclase enzyme to increase proaction of cGMP and cause smooth muscle relaxation

Nitric Oxide

13

B1 receptors cause?

Heart excitation

14

B2 receptors cause?

vasodialtion

15

what is a powerful vasoconstrictor that regulates systemic blood pressure

Angiotensin II

16

what is Nitric Oxide synthesized from

Arginine and O2 in the endothelial cells

17

Hypotension, elevated JVP, and muffled heart sounds are known as the Beck Triad and indicate what

cardiac tamponade

18

Late diastolic collapse of the right atrium and pericardial fluid accumulation is seen in

cardiac tamponade (due to fluid displacement when the ventricles expand)

19

what is the exaggerated drop is systolic BP (>10) during inspiration called

plusus paradoxus

20

Plusus Paradoxes can occur in what 5 pathologies?

cardiac tamponade
hypovolemic shock
asthma
COPD
constrictive pericarditis

21

voltage gated L-type Calcium channels with a large influx of Ca2+ into the cell open at what phase in the cardiac cycle

Phase 0: depolarization

22

closure of L-type Calcium channels and the opening of K+ channel is seen in which phase of the cardiac cycle

Phase 3: repolarization

23

slow influx of sodium beginning at the end of depolarizations happens in what phase of the cardiac cycle

Phase 4: pacemaker potential

24

how does adenosine slow down phase 4

it acts on the A1 receptors on the cardiac cells and activates potassium channels causing the membrane potential to remain negative for longer periods of time

also inhibits L-type calcium channels

25

what is useful to give for paroxysmal supra ventricular tachycardia

adenosine

26

what is the abrupt cessation of organized cardiac activity causing an inability to maintain adequate tissue perfusion

Suden Cardiac Death SCD

27

what is the most frequent mechanism of SCD in the first 48 hours after and acute MI and is related to electrical instability due to lack of perfusion to the ischemic myocardium

Ventricular Fibrillation

28

occlusion of the LAD most commonly present with what

ventricular septal rupture

29

what two things reduce the rate of phase 4

Adenosine and Ach

30

what type of calcium channels are opened in phase 4

t-type