Fish
In some fish, a rete mirabile fills the swim bladder with oxygen, increasing the fish's buoyancy. A countercurrent exchange system is utilized between the venous and arterial capillaries. By lowering the pH levels in the venous capillaries, oxygen unbinds from blood hemoglobin. This causes an increase in venous blood oxygen concentration, allowing the oxygen to diffuse through the capillary membrane and into the arterial capillaries, where oxygen is still sequestered to hemoglobin. The cycle of diffusion continues until the concentration of oxygen in the arterial capillaries is supersaturated (larger than the concentration of oxygen in the swim bladder). At this point, the free oxygen in the arterial capillaries diffuses into the swim bladder via the gas gland.
The Rete Mirabile allows for an increase in muscle temperature in regions where this network of vein and arteries is found. The fish is able to thermoregulate certain areas of their body. Additionally, this increase in temperature leads to an increase in basal metabolic temperature. The fish is now able to split ATP at a higher rate and ultimately can swim faster.
Read more about this topic: Rete Mirabile
Famous quotes containing the word fish:
“Of all nature’s animated kingdoms, fish are the most unchristian, inhospitable, heartless, and cold-blooded of creatures.”
—Herman Melville (1819–1891)
“If a fish is the movement of water embodied, given shape, then cat is a diagram and pattern of subtle air.”
—Doris Lessing (b. 1919)
“Remember the waterfront shack with the sign FRESH FISH SOLD HERE. Of course it’s fresh, we’re on the ocean. Of course it’s for sale, we’re not giving it away. Of course it’s here, otherwise the sign would be someplace else. The final sign: FISH.”
—Peggy Noonan (b. 1950)