Ventilators are often used for individuals with COVID-19 to increase the rate of diffusion of gases across the alveoli. Ventilators could increase the rate of diffusion by impacting which factor of Fick’s law of membrane diffusion: a   decreasing the diffusion coefficient (D) b   decreasing surface area (A) c   increasing the partial pressure difference (P1-P2) d   increasing the diffusion distance  e   all of the above

Below are multiple oxygen binding affinity curves for hemoglobin. The affinity curve for normal hemoglobin in blood is represented by curve "D," at a pH of 7.2 and at a concentration of 5mM BPG and 26 mM CO2. O₂ saturation (%) 100 Answer 1: B Answer 2: [Select] Answer 3: B Answer 4: 80 A 60 1. How would changes to acidity, BPG concentration and CO₂ levels affect the binding affinity curve and p50? lower than Answer 5: E 40 1. BPG concentration is decreased to 3mM: The binding affinity curve would look like B. The p50 would be lower than normal (D). 2. pH is increased to 7.6: The binding affinity curve would look like B. The p50 would be [Select] normal (D). 20 3. CO₂ concentration is increased to 30 mM: The binding affinity curve would look like. [Select] The p50 would be Answer 6: 0 normal (D). II. The hemoglobin has been treated with a denaturing solution which disrupts quaternary structure only, and has a binding affinity resembling myoglobin. The binding affinity curve would look…

Use the Hill Equation to determine the fractional saturation of hemoglobin in equilibrium with blood that has a partial pressure of 1.9 mmHg.

Helium gas is maintained at a partial pressure in alveolar gas of PHe,alv= 10 mmHg. Blood flow through the lungs is 5 L/min, the permeability surface area of the alveolar blood-gas barrier is PHe,M S= 100 mL/s, and Bunsen solubility coefficients for He in blood and barrier are a*He,blood= 0.008 mL He/(mL blood* atm) and a*He,M= 0.08 mL He/(ml blood* atm), respectively. Helium is not present in the inlet blood. Find the He flow across the microvascular barrier of the lung. Compare this with the maximum helium exchange for very high flow rates (diffusion limited). Compare the result in part (a) with the He flow when the permeability is very high (flow- limited).