Ventilation and Perfusion

Question 1

ventilation

Answer 1

process by which air moves in and out of lung

Question 2

perfusion

Answer 2

process by which deoxygenated blood passes through lungs and becomes oxygenated

Question 3

what does the ventilation: perfusion ratio determine

Answer 3

Levels of O2 and CO2 in the blood

Question 4

what effects does gravity (down and away from chest walls) have on the distribution of ventilation in the lungs

Answer 4

• pleural pressure is more negative at the apex than the base
• transpulmonary pressure is greater at base than apex
• increased alveolar volume in apex

Question 5

compliance

Answer 5

refers to elasticity of the tissue, high compliance = lungs and chest wall expand easily
decreased compliance is common in pulmonary conditions

Question 6

resistance

Answer 6

refers to any narrowing or obstruction of the airways.

high resistance is common in pulmonary conditions

Question 7

what are the two types of dead space

Answer 7

• anatomical - volume of gas from each breath that fills the conducting airways
• physiological - total volume of gas in each breath not used in gas exchange e.g alveoli filled but not perfused

Question 8

pulmonary circulation

Answer 8

brings deoxygenated blood from the heart to the lungs to be oxygented

Question 9

bronchial circulation

Answer 9

brings oxygenated blood to lung tissues

Question 10

what effect does gravity have on pulmonary circulation

Answer 10

greater blood flow to the base than the apex

Question 11

anatomical shunt

Answer 11

sees deoxygenated blood bypass the pulmonary capillaries therefore bypassing gas exchange

Question 12

physiological shunt

Answer 12

seen when there is an obstruction in the airways meaning alveoli not ventilating therefore blood passing is not perfused

Question 13

COPD

Answer 13

airflow obstructed

includes emphysema and chronic bronchitis

Question 14

pulmonary fibrosis

Answer 14

decreases elasticity and gas exchange