Gas Diffusion Flashcards
What is bronchial circulation supplied by?
The bronchial arteries arising from the systemic circulation to supply oxygenated blood to lung tissues.
Where does bronchial circulation drain?
Blood drains to the left atrium via pulmonary veins.
What does pulmonary circulation consist of?
The left and right pulmonary arteries originate from the right ventricle. All cardiac output comes from the right ventricle.
What does pulmonary circulation supply?
The dense capillary network surrounding the alveoli and returns oxygenated blood to the left atrium via the pulmonary vein.
What type of system is pulmonary circulation?
High flow, low pressure.
25/10mmHg compared to 120/80mmHg.
Describe partial pressures in venous blood.
Tissues = venous blood = pulmonary artery.
PO2 = 40, PCO2 = 46.
What affects the rate of diffusion?
Partial pressure gradients.
Gas solubility.
Available surface area.
Membrane thickness.
Describe the partial pressure gradients between the alveoli and the pulmonary artery.
A high gradient of O2 into the pulmonary artery.
A low gradient of CO2 into the alveoli.
What property does CO2 have that allows it to diffuse quickly?
More soluble in water than O2.
How are alveoli specialised for gas diffusion?
Large surface area.
Thin membrane for a short diffusion distance.
Elastic fibres between alveoli never lie between the blood cells and Type I alveolar cells.
