B4.064 - Microcirculation and Organ Blood Flow

Question 1

ischemia/reperfusion leads to the creation of what

Answer 1

generation of ROS

Question 2

what does the generation of ROS from ischemia/reperfusion lead to

Answer 2

damage to endothelial cells
inactivation of NO
increased formation of ET-1

Question 3

what is the difference between contractile force with and without endothelium

Answer 3

ACh increases contractile force without endothelium

decreases contractile force with endothelium

Question 4

what happens with leukocytes after ischemia/reperfusion

Answer 4

increased leukocytes adherence

Question 5

antioxidants

Answer 5

superoxide dismutase
catalase
lipoic acid

Question 6

what is a danger of giving IV NO

Answer 6

its a potent vasodilator so if you give it IV it will dilate throughout systemic arterioles decreasing TPR and causing arterial BP to fall aka shock

Question 7

what would a local intra arterial infusion of NO do to a transplanted organ

Answer 7

dilate arterioles within that organ, increasing blood flow to that organ and increasing capillary pressure which would promote edema

Question 8

in the case of head trauma leading to cerebral edema what happens

Answer 8

there is a loss of plasma across damaged vessels within the brain promoting edema, reducing oncotic pressure gradient and reducing the force for reabsorption of fluid from the cerebral interstitial space.

Question 9

as edema in the brain becomes more severe what happens

Answer 9

intracranial pressure will progressively increase and compress the veins, which increases vascular resistance and decreases cerebral blood flow

Question 10

what are some remedies to cerebral edema

Answer 10

hyperventilation

give mannitol

Question 11

why does hyperventilation work for cerebral edema

Answer 11

reducing arterial PCO2 levels will cause cerebral arteriolar vasoconstriction. This will reduce capillary pressure and thus the rate of filtration

Question 12

will cerebral arterioles remain constricted as long as the person hyperventilates?

Answer 12

No. Eventually vasodilator metabolites will accumulated in the brain and cause cerebral arteriolar dilation

Question 13

what is mannitol

Answer 13

mannitol is rapidly excreted by the kidney causing increased fluid excretion

Question 14

how does mannitol work for cerebral edema

Answer 14

IV mannitol would increase solute concentration in plasma which would increase the rate of reabsorption of fluid from the interstitial space of the brain

Question 15

what happens in lymphatic obstruction

Answer 15

decreased removal of fluid and protein from interstitium, increased interstitial protein, decreased oncotic reabsorption of fluid all leading to edema

Question 16

swelling in the leg due to lymphatic obstruction is particularly difficult to manage because

Answer 16

when the person stands venous pressure will increase in the legs and this will increase capillary pressure causing increased filtration of fluid into the interstitial space in the legs

Question 17

how does edema affect oxygen consumption

Answer 17

edema increases the diffusion distance between blood vessels and cells, thus making O2 distribution more difficutl

Question 18

in the context of cirrhosis how does edema in GI organs affect this

Answer 18

edema in GI organs causes hypoxia, and metabolic vasodilators will accumulate in the interstitial fluid, causing dilation of arterioles. This dilation will increase blood flow into the portal vein and increase the severity of portal hypertension

Question 19

what is ascites

Answer 19

accumulation of fluid in abdominal cavity

Question 20

what is active hyperemia

Answer 20

exercise
when the metabolic rate of skeletal muscle increases tissue O2 level decreases resulting in increased formation of vasodilator metabolites.

Question 21

decreased vascular resistance of skeletal muscle in active hyperemia causes what

Answer 21

increased skeletal muscle blood flow. This causes TPR to be reduced, stimulating the baroreflex to increase CO

Question 22

how does exercise affect systemic arterial pressures

Answer 22

low TPR means increased runoff, lowers arterial diastolic BP (despite increase in HR), increased pulse pressure due to increased SV

Question 23

cause of swelling in burnt legs?

Answer 23

activation of circulating leukocytes
impaired lymph flow
increased capillary pressure due to art. dilation
increased vascular permeabllity