Coronary and pulmonary circulation

Question 1

most transmural MIs occur in what areas of the heart?

Answer 1

anterior LV

inferior LV

Question 2

in which leads are anterior LV transmural MIs best seen?

Answer 2

precordial leads
lead I
aVL

Question 3

in which leads are inferior LV transmural MIs best seen?

Answer 3

lead II
lead III
aVF

Question 4

changes in the ECG at the

precordial leads
lead I
aVL

indicate an MI in which area of the heart?

Answer 4

anterior LV

Question 5

changes in the ECG at the

lead II
lead III
aVF

indicate an MI in which area of the heart?

Answer 5

inferior LV

Question 6

the heart is perfused primarily during what phase of the cardiac cycle?

Answer 6

ventricular diastole (rapid filling)

Question 7

as LV pressure decrease, what happens to blood flow?

Answer 7

decrease

Question 8

why is phasic blood flow of coronary circulation less pronounced on the right side?

Answer 8

less pressure (to open pulmonic valve)

Question 9

what is the relationship of flow and pressure in coronary circulation?

Answer 9

flow = change in pressure / resistance

Question 10

when is the change in aortic pressure lowest?

Answer 10

isovolumic contraction

Question 11

definition: myogenic autoregulation

Answer 11

being able to actively maintain a constant blood flow

intrinsic mechanism of vascular smooth muscle cells

Question 12

definition: coronary reserve

what is it related to?

Answer 12

difference between autoregulation and actual vasodilatory capacity of the vessels

related to how well the vessels can open and close (vasodilate) in response to incoming pressure

Question 13

what are the metabolic steps of oxygen regulation?

Answer 13

increased metabolism 
increased hypoxia 
increased ATP turnover 
increased cellular adenosine accumulation 
vasodilation

Question 14

what are the two phases of sympathetic regulation in coronary circulation?

Answer 14

1. transient vasoconstriction due to direct action of NE on alpha receptors
2. increased force of contraction and HR (metabolic vasodilation)

Question 15

hypoxis elicits what response in the coronary vasculature? what mediates this response?

Answer 15

vasodilation

adenosine

Question 16

what are the passive regulatory mechanisms for pulmonary blood flow through the circuit?

Answer 16

1. recruitment - opening of previously closed capillaries
2. distension - accommodation of increased blood volume
3. gravity, position, lung volume, alveolar and intrapleural pressure, intravascular pressures, RV output

Question 17

what are the active regulatory mechanisms for pulmonary blood flow through the circuit?

Answer 17

1. hypoxic vasoconstriction

2. other metabolites

Question 18

what is the effect of hypoxia on vasculature in the lungs?

Answer 18

vasoconstriction

Question 19

what is the rationale for pulmonary vasoconstriction in response to hypoxia?

Answer 19

blood is diverted to better ventilated alveoli - maintains V:Q matching

Question 20

what occurs in the late stages of pulmonary artery hypertension?

Answer 20

failing (right) heart can no longer generate enough pressure to maintain CO

Question 21

what occurs in the early stages of pulmonary artery hypertension?

Answer 21

CO is initially compensated by neuronal and humoral factors - contributes to further increases in PAP