Pulmonary Flow Flashcards
(21 cards)
What is the difference between bronchial circulation and pulmonary circulation?
Bronchial circulation delivers oxygen and takes CO2 from lung tissues, pulmonary circulation takes blood to the lungs for gas exchange
What type of blood does the pulmonary artery carry?
Deoxygenated
What type of blood does the pulmonary vein carry?
Oxygenated
What type of blood as the same gas composition as the alveoli?
Arterial
What type of blood has the same composition as the body’s cells?
Veinous
Why is the partial pressure gradient of O2 so close to the partial pressure gradient of CO2 in the alveoli despite the massive difference in partial pressures?
CO2 is much more soluble in water
What cells in the alveoli are capillaries always adjacent to?
Type I pneumocytes
Why is gas exchange decreased in a pulmonary oedema?
The fluid pushes the alveoli away from the capillaries
Where is pulmonary blood flow greatest?
At the base of the lung, due to gravity
At which level are blood flow and ventilation equal?
Rib 3
Why does smoking cause emphysema?
The chemicals activate elastin which destroys the elastase in the lungs
When talking about partial pressures,what do A, a, and
ṽ mean?
A - Alveolar
a -Arterial blood
ṽ - Mixed venous blood1
What is directly proportional to the rate of gas diffusion?
The partial pressure gradient
The gas solubility
The available surface area
What is inversely proportional to the rate of gas
diffusion?
The thickness of the membrane
What are the partial pressure gradients in the alveoli?
O2 - 100mmHg-40mmHg (13.3kPa-5.3kPa)
CO2 - 46mmHg-40mmHg(6.1kPa-5.3kPa)
What are the gas exchange rates of O2 and CO2 in the alveoli?
O2 - 250mls/min
CO2 - 200mls/min
What is shunt?
Blood flowing from the right side to the left side of the heart without being supplied with oxygen or having its CO2 removed
What is the ideal ratio of perfusion/ventilation?
1:1
What is alveolar dead space?
Alveoli with air that can’t be used for gas exchange
What is physiological dead space?
The sum total of alveolar dead space and anatomical dead space
Where does the majority of mismatch of perfusion/ventilation happen?
Apex of the lung
