Question

Write short notes on the renal threshold.

Answer 1

Hint: Renal is a medical term used for referring to a kidney. It is used in referring to any abnormalities relating to, involving, and/or located in regions of the kidneys. A threshold is a particular level of substance concentration, below or above which is considered as abnormal levels.

Complete answer:
-The renal threshold is the concentration level of substances (like glucose, proteins, ions, bicarbonates, creatinine, etc) present in the blood and is prevented from passing through the kidney into the urine. That is the highest concentration up to which a substance can be reabsorbed completely by glomerular filtrate and above this concentration, it is filtered out in the urine.
-The renal threshold varies for different substances based on the need of that particular substance in the body. Urine is thus used to diagnose many conditions, where the high concentration of different substances is an indication of abnormalities related to different mechanisms in the body.
-The renal threshold is measured to diagnose conditions like diabetes, pregnancy, kidney disorders, etc.

Additional information:
Changes in the concentration of substances above the renal threshold cause different abnormalities and diseases. For example, when the concentration of a glucose increases more than the renal threshold the reabsorption by glomerulus is incomplete leading to the presence of glucose in the urine, a condition known as Glycosuria or glucosuria.

Note:
Primary function of the kidney is for the regulation of blood volume and blood pressure. Other than this kidney is widely known for its filtration activity, which helps in regulating the concentration of the different substances in the blood, detoxification, and deamination of amino acids for use by other tissues.