Physiology 3.3 Flashcards
(38 cards)
Describe the process of gas exchange in a normal lung.
In a normal lung, ventilation takes place, leading to a normal partial pressure of oxygen inside the alveoli. Deoxygenated blood from the pulmonary artery undergoes gas exchange, loading oxygen into the blood, resulting in richly oxygenated blood leaving the lung.
What impact does emphysema have on gas exchange in the lungs?
Emphysema leads to a reduction in surface area available for gas exchange, impacting diffusion and resulting in less oxygen entering the blood. This leads to lower partial pressure of oxygen in the pulmonary vein and subsequently in systemic arterial blood.
How does fibrosis affect gas exchange in the lungs?
Fibrosis results in the thickening of the alveolar membrane, slowing down gas exchange. It also decreases lung compliance, impacting alveolar ventilation and leading to a lower partial pressure of oxygen in the blood leaving the lungs.
Define the impact of reduced surface area on gas exchange in emphysema.
Reduced surface area in emphysema leads to less gas exchange taking place, resulting in a lower partial pressure of oxygen in the blood leaving the lung.
Do conditions like emphysema and fibrosis affect the partial pressure of oxygen in the pulmonary vein and systemic arterial blood?
Yes, both emphysema and fibrosis lead to a lower partial pressure of oxygen in the pulmonary vein and subsequently in systemic arterial blood.
Describe the impact of fibrous tissue on the alveolar membrane in fibrosis.
Fibrous tissue laid down in fibrosis increases the thickness of the alveolar membrane, slowing down gas exchange and impeding diffusion.
How does fibrosis affect lung compliance and alveolar ventilation?
Fibrosis decreases lung compliance, making it difficult to expand the lungs during inspiration, which impacts alveolar ventilation and leads to a lower partial pressure of oxygen inside the alveoli.
Define the impact of thickened alveolar membrane on gas exchange in fibrosis.
Thickened alveolar membrane in fibrosis slows down gas exchange, as it increases the thickness of the tissue across which the gas has to diffuse.
Describe the impact of pulmonary edema on the distance across which gas has to diffuse.
Pulmonary edema increases the distance across which gas has to diffuse by causing fluid to sit between the alveoli and the capillaries, pushing them apart.
Define pulmonary hypertension and its role in causing pulmonary edema.
Pulmonary hypertension is an increase in blood pressure in the pulmonary capillaries, which forces plasma out of the capillaries and into the interstitial space, leading to pulmonary edema.
How does pulmonary edema affect the partial pressure of oxygen in the pulmonary vein and systemic arterial blood?
Pulmonary edema leads to a reduction in the partial pressure of oxygen in the pulmonary vein and systemic arterial blood due to the increased diffusion distance and the presence of water, in which oxygen does not dissolve well.
Describe the impact of pulmonary edema on the diffusion of carbon dioxide.
Pulmonary edema often results in a normal partial pressure of carbon dioxide, as carbon dioxide is much more soluble in water than oxygen, allowing it to continue to diffuse despite the increased diffusion distance.
Do fibrosis and emphysema have a similar impact on the diffusion of oxygen as pulmonary edema?
No, fibrosis and emphysema impact the diffusion of oxygen, but with pulmonary edema, the main target is the effect on the diffusion of oxygen, with a much smaller impact on the diffusion of carbon dioxide.
Describe the difference in impact on diffusion between asthma and pulmonary edema.
Asthma does not directly impact diffusion, whereas pulmonary edema significantly affects the diffusion of oxygen, with a smaller impact on the diffusion of carbon dioxide.
Describe the impact of asthma on the partial pressure of oxygen in systemic arterial blood.
Asthma leads to a low partial pressure of oxygen in systemic arterial blood due to reduced ventilation, causing a decrease in oxygen entering the alveoli.
Define the primary issue in asthma and its effect on ventilation and diffusion.
Asthma primarily affects ventilation by causing inappropriate constriction of bronchiole smooth muscle or inflammation, leading to a reduction in oxygen entering the alveoli and difficulty in getting carbon dioxide out.
How does fibrosis impact ventilation and diffusion in the lungs?
Fibrosis results in a reduction in ventilation due to resistance to lung expansion during inspiration and impedes diffusion due to the thickened fibrous tissue, causing a decrease in oxygen entering the blood.
Describe the difference in the impact on ventilation between emphysema and fibrosis.
Emphysema primarily affects exhalation due to reasons to be discussed, while fibrosis mainly affects inspiration, making it difficult due to the resistance from fibrous tissue.
Do asthma, emphysema, and fibrosis all have issues with diffusion in the lungs?
Asthma primarily affects ventilation, emphysema may have some impact on diffusion, and fibrosis impedes diffusion due to the thickened fibrous tissue.
Define the role of fibrous tissue in fibrosis and its impact on lung function.
Fibrous tissue in fibrosis resists lung expansion during inspiration, leading to a reduction in ventilation, and also impedes diffusion due to the thickened membrane, causing difficulty for gases to diffuse through.
Describe the appearance of fibrotic tissue on an X-ray.
Fibrotic appears radiopaque on an X-ray, making visible as dense, white areas.
What impact does fibrotic tissue have on breathing?
Fibrotic tissue resists lung expansion during inspiration, making it difficult for the patient to breathe.
Define pulmonary edema.
Pulmonary edema is the accumulation of fluid in the airspaces and tissues of the lungs, leading to difficulty in oxygen diffusion.
How does pulmonary edema affect gas exchange in the alveoli?
Pulmonary edema increases the distance across which gas in the alveoli has to diffuse to reach the blood vessels, impacting oxygen diffusion due to poor solubility in water.
