Respiration Lecture 08: Distribution of Ventilation and Lung Perfusion

Question 0

2 main causes of hypoxemia

Answer 0

1) increase in thickness of diffusion barrier due to i.e. infection, edema, pulmonary hypertension, swelling
2) loss of surface area of diffusion barrier

Question 1

Hypoxemia

Answer 1

low blood oxygen

Question 2

more negative Ppl –> PTP?

Answer 2

PTP also becomes more negative

Question 3

Which area of the lung is most ventilated?

Answer 3

basal region due to gravity

Question 4

Is PO2 greater in apical or basal region?

Answer 4

apical

Question 5

Is PCO2 greatest in apical or basal region of lung?

Answer 5

basal

Question 6

Why does L heart generate larger pressure than R heart?

Answer 6

Must supply blood to all of systemic circulation

Question 7

increased lung volume –> alveoli and capillaries?

Answer 7

Alveoli expand, capillaries tend to collapse

Question 8

Gravity prevent regional collapse of pulmonary capillaries

Answer 8

.

Question 9

transit time

Answer 9

amt. of time a bollus of blood sits in gas exchange space.

Question 10

Increased cardiac output –> transit time

Answer 10

increases(?)

Question 11

What percent of cardiac output goes through pulmonary vasculature?

Answer 11

100%

Question 12

4 main functions of pulmonary vasculature

Answer 12

1) acts on all blood contents
2) filters
3) regulates blood enzymes
4) activates/deactivates venous molecules

Question 13

Ventilation to perfusion ratio (VA/Q)

Answer 13

estimates the match between blood perfusion of a pulmonary capillary around an alveolus and the ventilation of the alveolus

Question 14

bronchial circulation

Answer 14

part of systemic circulation that provides oxygenated systemic blood to the bronchi. Doesn’t usually get into gas exchange areas

Question 15

Physiological Dead Space**

Answer 15

• alveolar regions of the lung that are ventilated but don’t have blood flowing through the adjacent pulmonary capillaries.
• Doesn’t participate in gas exchange
• Combination of ANATOMICAL dead space + ventilated but unperfused alveoli
• Will always exceed anatomical dead space