respiration VQ relationship

Question 1

what is ventilation?

Answer 1

process by which air moves in and out of the lungs

Question 2

what is perfusion?

Answer 2

process by which deoxygenated blood passes through lungs and becomes oxygenated

Question 3

what is the V/Q ratio?

Answer 3

Major determinant of normal gas exchange and thus the level of PO2 and PCO2 in blood is the relationship between ventilation and perfusion.

Question 4

what causes ventilation to not be uniformly distributed in the lung?

Answer 4

gravity

Question 5

what part of the lung is more expanded in the upright position?

Answer 5

alveoli in apex

Question 6

is pleural pressure more negative at the apex or base?

Answer 6

apex

Question 7

is transpulmonary pressure greater at the apex or base?

Answer 7

apex

Question 8

what is compliance?

Answer 8

how much effort is required to stretch the lungs and chest wall

Question 9

what does high compliance mean?

Answer 9

lungs and chest wall expand easily

Question 10

what are common pulmonary conditions in which decreased compliance is common?

Answer 10

Scarring in lung tissue (tuberculosis)
Lung filled with fluid (edema)
Deficiency in surfactant production
Destruction of elastic fibres (emphysema

Question 11

what is resistance?

Answer 11

any narrowing or obstruction of the airway that may reduce airflow

Question 12

what pulmonary conditions is increased resistance common?

Answer 12

Asthma
COPD (emphysema, chronic bronchitis) due to obstruction or collapse of airways.

Question 13

what are the two types of dead space?

Answer 13

anatomical and physiological

Question 14

what is anatomical dead space?

Answer 14

volume of gas during each breath that fills the conducting airways

Question 15

what is physiological dead space?

Answer 15

Total volume of gas in each breath that does not participate in gas exchange, e.g., alveoli that are perfused but not ventilated.

Question 16

what are the two blood supplies of the lungs?

Answer 16

pulmonary and bronchial

Question 17

what is the pulmonary blood supply of the lungs?

Answer 17

brings deoxygenated blood from heart to lung and oxygenated blood from lung to heart.

Question 18

what is the bronchial circulation of the lungs?

Answer 18

brings oxygenated blood to lung parenchyma

Question 19

which circulation system is more influenced by gravity?

Answer 19

pulmonary (low pressure low resistance)

Question 20

what is the V/Q ratio in a single alveolus defined as?

Answer 20

alveolar ventilation divided by capillary flow

Question 21

what is the V/Q ratio in a lung defined as?

Answer 21

total alveolar ventilation divided by cardiac output

Question 22

when is V/Q >1?

Answer 22

ventilation exceeds perfusion

Question 23

when is V/Q <1?

Answer 23

perfusion exceeds ventilation

Question 24

apical vs base lung V/Q

Question 25

what is an anatomical shunt?

Answer 25

Mixed venous blood ‘shunted’ directly into arterial blood.
(incase of lung – mixed pulmonary artery blood shunted into pulmonary veins)

Question 26

what does a right to left anatomical shunt lead to?

Answer 26

dilute amount of oxygen circulating body

Question 27

what is a physiological shunt?

Answer 27

alveolar sacs aren’t ventilated due to blockage

Question 28

what is atelectasis?

Answer 28

obstruction of ventilation due to mucous plugs, airway oedema, foreign bodies, tumours in airways

Question 29

what is COPD?

Answer 29

chronic obstructive pulmonary disease
- condition in which airflow is obstructed
- encompases emphysema and chronic bronchitis
- most common in long term smokers
- chronic cough, tight chest, shortness of breath, increased mucous production

Question 30

what is emphysema>

Answer 30

• Structures in alveoli over inflated.
• Lungs loose elasticity, cannot fully expand and contract.
• Patients can inhale but exhalation is difficult due to decreased elastic recoil.

Question 31

what is chronic bronchitis?

Answer 31

• Inflammation of bronchi causing mucous production and excessive swelling.
• Shortness of breath with mild exertion.
• Chest infections more prevalent.
• difficult for air to get into the lung

Question 32

what is pulmonary fibrosis?

Answer 32

• A type of interstitial lung disease.
• Scarring and thickening of tissue.
• Decreased elasticity.
• Decreased gas exchange.
• patient diagnosed will normally die within 4 years