Table 2, percentages of solutes in Blood plasma, Glomerular filtrate, quantity reabsorbed and urine per day.
From this table, we can see that all the proteins and glucose that enters the kidneys are reabsorbed into the blood stream, 0% of them are excreted in the urine. Almost 100% of the protein does not ever enter the glomerular filtrate, but any that does is reabsorbed. From table 1 and 2 it is visible that very little of the ion substances, (sodium, chloride, hydrogen carbonate and potassium) are excreted, the majority of their value is reabsorbed into the blood and only a very small percent is excreted. By comparing Table 1 and 2 it is possible to see that a very large amount of glucose passed through the kidneys but never gets excreted (according to the data presented).
By looking at the percentages on the solutes in the urine, we can see what the kidneys job is in the body in more detail as it is possible to see what exactly is removed from the blood stream. (Table 3 and chart 1)
Table 3, Percentages of substances in Urine.
The majority of urine is made up of Urea which is removed form the blood by the kidneys. However, by comparing this with Table 2, we see that only 15.7% of Urea is excreted, and 17.6% is reabsorbed into the blood. Showing that not all of the solute is excreted, and that some remains in the blood to maintain a balance. It is the same for the uric acid, of which only 3.14% is excreted and 30.2% is reabsorbed back into the blood having passed through the filtrate. Hydrogen carbonate, Sodium and chloride ions make up a small percentage of the substances found in the urine, the majority is reabsorbed into the body, however, not all of it is able to re enter the blood stream thus it is excreted.
Conclusion
Through the data presented in this lab, the functions of the kidney are clearly defined. The glucose is effectively reabsorbed back into the blood by active transport and the structure of the proximal convoluted tubule. So are amino acids, vitamins, hormones sodium ions and other small soluble minerals and ions. As seen from the results.
A surprisingly large percentage of the urea also escapes from the kidney and moves back into the tissue fluid and blood. This is due to the small size of the urea molecules and their ability to pass freely through cell surface membranes. It diffuses down a concentration gradient from the nephron into the tissue fluid and blood. However, despite this, the kidney manages to perform its main function in excreting a large amount of the substance. The fact that the kidneys do not allow glucose to be excreted is a good way of testing for problems. If someone’s urine contains glucose, it is likely that they have something wrong with their proximal convoluted tubule. Water is a vital substance in our bodies. A huge percentage of our bodies is made of it, thus without it there is no ways we could survive. The kidneys are specially made so that very little of the water that passes through them is excreted. As seen in table 1, the only water that is lost, is used to dilute the urea that is being excreted. Thus, water loss will be in direct relation to the amount of urea removed from the blood. The kidney allows water molecules to pass through via osmosis back into the body.
The kidney is a complex structure which is vital for our existence. Often people have to have transplants as they have kidney failures. It separates the harmful substances in our bodies from the substances we need most. This data shows what those substances are and how the kidney divides them into what needs to be excreted and how much need to be excreted.
