Blood Flow and Metabolism

Question 1

Fick Principle

equation

Answer 1

Q_p = V_O2 / [C_AO2 - C_VO2]

Question 2

Respiratory Quotient

Answer 2

respiratory quotient = CO₂ formation/ O₂ consumption

Question 3

Respiratory quotient values and meanings

Answer 3

0. 8: normal, burning adipose reserves
1. 0: aerobic exercise, burning carbohydrates

>1.0: anaerobic respiration, more CO₂ being produced than O₂ is being consumed

Question 4

Normal pulmonary artery pressure

Answer 4

25/8

Question 5

Saturations in pulmonary artery

Answer 5

pO₂: 40

pCO₂: 46

Question 6

Pathologies affecting alveolar pressure

Answer 6

tension pneumothorax

⇒ death from venous compression

positive-pressure breathing

⇒ CPAP machine

Question 7

3 possible pulmonary zones

Answer 7

Zone 1: P_A > P_art > P_v

Zone 2: P_art > P_A > P_v

Zone 3: P_art > P_v > P_A

Question 8

Pulmonary Zone 1

Answer 8

P_A > P_art > P_v

*only occurs in pathologies like tension pneumo, hemorrhage, or positive-pressure breathing

no flood flow in this region

⇒ alveoli are collapsed

Question 9

Pulmonary Zone 2

Answer 9

P_art > P_A > P_v

*apex of lungs

perfusion depends on pressure gradient between pulmonary artery and alveoli

Question 10

Pulmonary Zone 3

Answer 10

P_art > P_v > P_A

*mid- and lower lungs

perfusion depends on pressure gradient between arterial and venous ends

Question 11

Hypoxic alveoli

what occurs

Answer 11

vasoconstriction

Question 12

Vasoconstriction in hypoxic alveoli

mechanism

Answer 12

blocking VG K⁺ channels

VG Ca²⁺ channels remain open

vasoconstriction

Question 13

ACE functions

Answer 13

ATI → ATII

bradykinin degradation

(results in cough sometimes)

Question 14

ACE is classically found

Answer 14

in lung tissue

anywhere with vascular endothelium really

but all CO goes to lungs

so it’s a good place to put ACE

Question 15

Lung parenchyma also synthesizes these molecules

Answer 15

leukotrienes

PGE2: keeps PDA open