Question

Though ventilation pattern may differ greatly, the goal of gas exchange is fairly consistent—to establish a relatively high oxygen partial pressure to blood.

a. Discuss how countercurrent gas exchange and cross-current gas exchange both strive to meet the above goal. Which mode is the most effective? Explain.

b. Which model system examined uses a unique ventilation method that may alter the decision made above? Explain

Answer 1

a) countercurrent mechanism:

This is a way of how ventilation occurs in fish where water carrying oxygen flows in one direction and blood picking oxygen flows in opposite direction to maximize oxygen diffusion to blood.

Cross current nechanism :

Respiratory medium is in one direction while flow of the blood is perpendicular to the direction of air flow.

—Crosscurrent is less efficient than countercurrent because blood doesn't move in exact opposite exactly opposite direction to air but is more efficient than tidal ventilation.

b) concurrent mechanism - blood flow in the same direction as the medium. Concurrent flow allows the pO2 of blood to equilibriate wiith p02 of respiratory medium .

This modal system is altering the statement to maintain a relatively high oxygen partial pressure .