The topic for this essay I chose:
Gills are very efficient at absorbing oxygen from the water. One “trick” to this ability is the countercurrent, in which blood and water flow in opposite directions. Explain how the countercurrent makes gas exchange more efficient.
Have you ever just observed the fishes, perhaps some sharks, or any other marine creature with gills, and thought how in the word do they breathe/function in the water? Unlike us human beings, these creatures what we call gills is what helps them move around breathing underwater. The way this works is that gills bring special red blood cells to oxygen source. To those of you who never been in the outdoor life and never saw such creatures as fish this is what gills look like:
Going back on topic a countercurrent gas exchange is when the water passes over gills and blow flows through gills in opposite directions. Water always encounters blood with lower Po2 (partial pressure of oxygen). Countercurrent makes gas exchange more efficient by having the blood level to low in o2 and high in Co2 and is transported to gills and lungs where gases can be exchanged. Gas moves from higher to lower partial pressure in a process known as diffusion.
That’s all for this essay. I hope you enjoyed reading it or learned something new from it. Although it would surprise for me to hear that no one ever saw a fish or shark in their life 😅. Anyways have a great rest of your day and I’ll be posting more soon.
Anastasia's Blog 