Pulmonary Blood Flow, Gas Exchange and Transport

Question 1

Bronchial circulation

Answer 1

Nutritive - supplied via bronchial arteries arising from systemic circulation to supply O2 to airway smooth muscle, nerves and lung tissue

Question 2

Pulmonary circulation

Answer 2

Gas exchange - L & R pulmonary arteries originating from right ventricle. Carries entire cardiac output. Supplies dense capillary network and returns oxygenated blood to the left atrium via the pulmonary vein

Question 3

Shunt

Answer 3

Passage of blood through areas of the lung that are poorly ventilated

Question 4

Alveolar dead space

Answer 4

Alveoli that are ventilated but not perfused

Question 5

Anatomical dead space

Answer 5

Conducting airways that do not participate in gas exchange

Question 6

Physiological dead space

Answer 6

Alveolar dead space + anatomical dead space

Question 7

Pulmonary circulation sytem

Answer 7

High flow, low pressure - same volume of blood flowing to the lungs as to entire body

Question 8

Miscellaneous

Answer 8

CO2 much more soluble than oxygen so passes through membrane more easily
Capillary always directly adjacent to type 1 alveolar cell - reduces distance for gas to diffuse

Question 9

Lung disease and gas exchange

Answer 9

Mainly has an effect on diffusion, except for asthma where there is a low PO2 in general

Question 10

Perfusion

Answer 10

Local blood flow

Question 11

Ventilation/perfusion relationship

Answer 11

Ideally compliment each other

Question 12

Blood flow in lungs

Answer 12

Inversely proportional to vascular resistance and declines with height across the lung

Question 13

Blood flow at base of lungs

Answer 13

Blood flow is high as arterial pressure (Pa) exceeds alveolar pressure (PA) and vascular resistance is therefore low

Question 14

Volume of O2 dissolved/L of plasma

Answer 14

3ml

Question 15

Haemoglobin

Answer 15

Increases O2 carrying capacity to 200ml/L

1.34ml O2 bound to each gram of haemoglobin

Question 16

CO2 transportation

Answer 16

In solution in plasma

Question 17

Arterial partial pressure of oxygen

Answer 17

Refers to O2 in solution and is determined by O2 solubility and partial pressure of O2 in the gaseous phase that is driving O2 into solution

Question 18

Forms of haemoglobin in the RBC

Answer 18

92% - HbA

Question 19

Anaemia

Answer 19

Any condition where the oxygen carrying capacity of the blood is compromised (eg. iron deficiency, vitamin B12 deficiency, haemorrhage)

Question 20

Hypoxia

Answer 20

Inadequate supply of oxygen to tissues

Question 21

Hypoxaemic hypoxia

Answer 21

Reduction in O2 diffusion at lungs either due to decreased PO2atmos or tissue pathology

Question 22

Anaemic hypoxia

Answer 22

Reduction of O2 carrying capacity of blood due to anaemia

Question 23

Stagnant hypoxia

Answer 23

Heart disease results in inefficient pumping of blood to lungs/around body

Question 24

Histotoxic anaemia

Answer 24

Poisoning prevents cells utilising oxygen delivered to them (eg. CO/cyanide

Question 25

Metabolic hypoxia

Answer 25

Oxygen delivery to the tissues does not meet increased oxygen demand by cells

Question 26

Ventilation

Answer 26

Air getting to alveoli