Why do longer loop of Henle's allow marine animals to remove excess salt from their bodies?????

Question

If humans drank only sea water, they would be unable to remove the excess salf from their bodies. Marine animals are able to remove excess salt because their loop of Henle is longer.

Answer 1

The function of the Loop of Henle is to create a very high concentration of salts in the medulla tissue fluid so water is reabsorbed and conserved.

Cells in the walls of the ascending limb pump Na+/Cl- out of the filtrate creating a high concentration around the descending limb. This draws water out by osmosis. As water leaves the filtrate, Na+/Cl- diffuses back into the tubule down their concentration gradient. Combined with the loss of water, the filtrate becomes increasingly concentrated with ions.

In the lower part of the ascending limb of the Loop of Henle, the concentration of ions in the filtrate is now so great that they diffuse out of the filtrate. The tissue fluid in the lower part of the medulla is extremely concentrated with ions and draws most water out.

The longer the Loop of Henle, the more this process is accentuated i.e. the greater the concentration build up of ions in the medulla and the more water removed. Another good example of such an adaptation is the kangaroo rat.

Answer 2

Because the loop of henle pulls salt out of the blood. Longer loop means more salt extraction.

Answer 3

Only a few creatures are apparently aware that they are aware, the apes, dolphins and elephants spring to mind. As you suggest, cats and dogs seem to be simply aware, not knowing of their own identity when confronting their image. Even so most creatures possess a consciousness, if you define it as an awareness of their surroundings. Perhaps at the very simplest level, awareness is in all living molecules, in our DNA, a genetic automatic protective survival trait or chemical reaction. The greater complexity of multicellular life forms indicates higher forms of consciousness, a nervous system developing into a brain; possibly natural selection harnessing greater awareness of external sensations by cooperation between cells. At some stage, in the so called higher animals, this cooperation could lead to a recognisable consciousness such as is seen in a cat or dog. Then in a few creatures meta-awareness develops for reasons of survival or even sociability. Whatever the reason for human consciousness existing in a material body made from atoms, there is no good reason to evoke a spiritual cause for which there is no evidence. Our extremely mysterious and wonderful conscious state is the product of our material make-up. "The whole is greater than the sum of its parts", far far greater.

Answer 4

longer loop of henle's means that more water reabsorption will take place . hence the urine gets more hypertonic and hence more salt will be removed