4- Coronary, Pulmonary, and Cerebral Circulations

Question 1

supplies the posterior left ventricle and right ventricel

Answer 1

right coronary a.

Question 2

supplies anterior LV

Answer 2

anterior descending a.

Question 3

supplying lateral LV free wall

Answer 3

left circumflex a.

Question 4

“extravascular compression” aka phasic blood flow

Answer 4

proximity of inner network of vessels to the blood volume of the ventricular chamber alters the distribution supply

Question 5

blood flow through the coronary circuit is high…

Answer 5

during diastole

Question 6

why are left subendocardial cesels more subject to ischemic injury than right

Answer 6

the left heart is subject to musch greater stree and compressive forces

Question 7

stretch activated ion channels respond to pressure changes directly

Answer 7

myogenic mechanism

Question 8

changes in teh generation and release of by-products of cardiac work

Answer 8

metabolic mechanism

Question 9

“adenosine hypothesis”

Answer 9

adenosine released after depletion of ATP in cardiac myocytes diffuses to nearby vascular smooth muscle cells and binds to adenosin receptor, activating an intracellular signal cascade to elicit vasodilation

Question 10

capacity of the vasculature to respond to a vasodialtory stimulus

Answer 10

coronary reserve

Question 11

biphasic effect of sympathetic stimulation on coronary blood flow

Answer 11

1. constrict (due to activation of alpha adrenergic receptors)
2. vasodilation (indirect effect on oxygen demand through beta adrenergi receptors)

second is the greater effect

Question 12

how are pulmonary vessels different than their systemic counterparts

Answer 12

more elastic and less smooth muscle (in order to accommodate entire CO )

Question 13

do pulmonary vessels have a myogenic response?

Answer 13

NO

Question 14

does hypoxic vasoconstriction happen anywhere but the lungs?

Answer 14

NO because the lungs don’t want to ‘waste’ ventilation

elsewhere in the body hypoxia –> greater perfusion

Question 15

supplies most of the forebrain

Answer 15

internal carotids

Question 16

supplies brain stem, cerebellum, occipital lobe and part of thalamus

Answer 16

vertebral aa.

Question 17

supplies occipital lobe and the choroid plexuses of the 3rd and 4th lateral ventricles and lower temporal lobe

Answer 17

posterior cerebral a.

Question 18

supplies deep structures of brain

Answer 18

middle cerebral a.

Question 19

supplies the frontal lobe and medial regions of cortex

Answer 19

anterior cerebral a.

Question 20

circumventricular organs

Answer 20

brain structures outside the blood-brain barrier

• subfornical organ
• organ vasculosum of lamina terminalis
• area postrema
• neurohypophysis

Question 21

important region in thrist response

Answer 21

SFO contains sensory machinery to taste peripheral circulation

Question 22

detecting ion balance

Answer 22

OVLT

Question 23

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

Answer 23

ventricular diastole

Question 24

difference between passive movement due to pressure and the autoregulatory curve (active maintenance of tension in vessel) =

Answer 24

coronary reserve

Question 25

what does chronic hypoxemia lead to …

Answer 25

increased resistance to flow which causes right ventricular hypertrophy and eventually right ventricular failure “cor pulmonale”

Question 26

where does most of the brain’s blood supply come from?

Answer 26

80% internal carotids