Respiratory System (II) Flashcards
Is ventilation equal throughout an alveoli? If not, where is ventilation greatest in the lungs?
Ventilation is not equal throughout an alveoli. It is greater at the base of the lungs as gravity impacts the blood flow and intrapleural pressure.
What is perfusion?
Perfusion is the blood flow and fluid to tissues and organs.
How can we quantitively understand if ventilation and perfusion rates are equal?
We use the V/Q ratio, where V is ventilation and Q is perfusion.
What are the different V/Q standards in a healthy individual?
- In the middle of the lungs = 1
- At the bottom of the lungs = 0.3
- At the apex of the lungs = 2.1
How can we modulate ventilation and perfusion in the lungs?
We can modulate by lowering oxygen delivery to the alveolar - this is done by vasoconstriction, decreasing blood flow and dilating the bronchioles. We can also increase carbon dioxide by dilating bronchioles for more efficient carbon dioxide/oxygen diffusion.
What are some diseases related to alveolar ventilation?
Restrictive pulmonary disorder (pulmonary oedema), obstructive pulmonary disorder (asthma) and masses (tumours).
What is pulmonary fibrosis?
When alveoli is abnormally large, has a lot of scarring and has thick tissue between alveoli.
What is pulmonary oedema?
When alveoli have fluid filled in them not air. The blood that is ineffectively pumped in the pulmonary circuit builds up pressure and is forced out. The alveoli collects this fluid.
What are the characteristics of asthma?
Asthma involves the chronic inflammation of the bronchiole tubes. During an attack, the smooth muscles of bronchiole tubes will tighten and trap the air in the alveoli.
What is chronic bronchitis?
inflammatory condition that causes an excess secretion of mucus, increased risk of infection and loss of ciliary function.
What is emphysema?
It is the loss of alveolar walls. It results in a large space for air and prevents new, rich-oxygen air to be re-filled.
How is airflow calculated?
Pressure gradient / Resistance
What is the blood pH that should be maintained?
Between 7.35-7.45
What is acidosis?
When pH goes below 7.35 and you start feeling disorientated - can lead to death. This results in a lower activity or depression of the nervous system. It increases the product of hydronium ions and carbonic acid. Carbonic acid builds up and can lead to lung disease and an inadequate perfusion and ventilation of the alveoli.
What is an example of acidosis?
Metabolic acidosis. This involves the kidneys and its inability to remove H+ from the blood. A build up of H+ or acid in the blood can cause a failure of the kidneys.
