Fish gills use a design called ‘countercurrent oxygen exchange’ to maximize the amount of oxygen that their blood can pick up. Countercurrent oxygen exchange (shown in the figure above) means the blood flows through the gills in the opposite direction as the water flowing over the gills.
countercurrent exchange. a biological mechanism designed to enable maximum exchange between two fluids. The mechanism’s effect is dependent on the two fluids flowing in opposite directions, and having a concentration gradient between them. fluid ONE. high concentration → low concentration.
One may also ask, where is countercurrent exchange found in the body? Some mammals, dogs for example, have a countercurrent heat exchanger located between the carotid arteries and the vessels that distribute blood to the brain. This heat exchanger transfers some of the heat of the arterial blood to the relatively cool venous blood returning from the nose and mouth.
Also know, what is countercurrent flow in fish?
Fish also have an efficient transport system within the lamellae which maintains the concentration gradient across the lamellae. The arrangement of water flowing past the gills in the opposite direction to the blood (called countercurrent flow) means that they can extract oxygen at 3 times the rate a human can.
Why is countercurrent exchange more efficient?
The exchanger is performing at its best when the outlet temperatures are equal. Counter flow heat exchangers are inherently more efficient than parallel flow heat exchangers because they create a more uniform temperature difference between the fluids, over the entire length of the fluid path.
What is an example of countercurrent exchange?
Countercurrent exchange in biological systems. For example, fish use it in their gills to transfer oxygen from the surrounding water into their blood, and birds use a countercurrent heat exchanger between blood vessels in their legs to keep heat concentrated within their bodies.
Why is countercurrent exchange important?
Fish gills use a design called ‘countercurrent oxygen exchange’ to maximize the amount of oxygen that their blood can pick up. Oxygen would quickly pass from the water into the blood, until the oxygen levels of the blood and water rapidly became the same, and oxygen diffusion into the blood would stop.
What is the principle of countercurrent exchange?
Countercurrent exchange is a mechanism occurring in nature and mimicked in industry and engineering, in which there is a crossover of some property, usually heat or some chemical, between two flowing bodies flowing in opposite directions to each other.
What is the purpose of countercurrent mechanism?
Quick points about Counter Current Mechanism: The function of the countercurrent multiplier is to produce the hyperosmotic Medullary Interstitium. The ADH promotes water reabsorption through the walls of the distal convoluted tubule and collecting duct.
What is a countercurrent blood supply?
Countercurrent Heat Exchange. Countercurrent Heat Exchange. Blood flowing from the body core to the periphery (like the legs & feet) carries heat that can be readily lost through the skin. However, the vein returning blood to the body core lies alongside the artery taking blood to the feet.
How does the Vasa recta work?
The vasa recta, the capillary networks that supply blood to the medulla, are highly permeable to solute and water. Because transport of salt and other solutes requires oxygen and adenosine triphosphate, reduced medullary blood flow decreases salt and solute transport by nephron segments in the medulla.
What is countercurrent exchange in the kidneys?
Countercurrent multiplication moves sodium chloride from the tubular fluid into the interstitial space deep within the kidneys. As a result, water moves passively down its concentration gradient out of the tubular fluid in the descending limb into the interstitial space, until it reaches equilibrium.
What is counter flow system?
counterflow system. the flow of water and blood in opposite directions across the gills of fish which ensures that blood meets water with the highest possible oxygen content. see COUNTERCURRENT EXCHANGE. Collins Dictionary of Biology, 3rd ed.
Where is the heart of fish located?
The heart is located a little behind and below the gills. The typical fish heart has four chambers, however unlike mammals, blood moves through all four in sequence. Venous blood enters the sinus venosus (a thin walled sac) then flows into the atrium, followed by the ventricle (a thick walled pump).
How do fishes sleep?
The simple answer is yes! They are sleeping, and they can sleep at any time during the day or night. Fish do sleep with their eyes open, because they don’t have eyelids (except for some sharks) to close! For fish, sleep is more like a resting period similar to a daydream that humans might experience.
Why is countercurrent flow important in fish?
The counter current system allows the maximum amount of oxygen to diffuse into the blood from the water available. This is important because there isn’t much oxygen in the water, and fish need to absorb enough oxygen to survive.
How does the heart of a fish work?
In fish, the heart only has one atrium and one ventricle. The oxygen-depleted blood that returns from the body enters the atrium, and then the ventricle, and is then pumped out to the gills where the blood is oxygenated, and then it continues through the rest of the body.
Why is one way flow an advantage to fish?
Because water is more vicious than air, it takes more energy to ventilate and swim through it. This causes an increase in demand for oxygen, and therefore fish have a continuous unidirectional flow of water over their gills for maximum diffusion efficiency.
How does gaseous exchange occur in fish?
Each filament contains a capillary network that provides a large surface area for exchanging oxygen and carbon dioxide. Fish exchange gases by pulling oxygen-rich water through their mouths and pumping it over their gills.