AEMCA Practice Exam

What is the primary waste product filtered out by the kidneys?

1. Glucose

2. Urea

3. Amino acids

4. Cholesterol

The correct answer is: Urea

The primary waste product filtered out by the kidneys is urea. Urea is a byproduct of protein metabolism and is formed in the liver following the breakdown of amino acids. Once formed, it enters the bloodstream and is transported to the kidneys, where it is filtered out of the blood and excreted in urine. The role of the kidneys is vital in regulating the body's electrolytes and maintaining homeostasis. Urea is particularly important as it helps to remove excess nitrogen from the body, which can be toxic in high levels. In normal physiological conditions, other substances such as glucose and amino acids are typically reabsorbed in the kidneys, as the body needs them for various metabolic processes. Cholesterol, while a significant lipid in the body, is not a waste product and is also not typically filtered out by the kidneys in the same manner as urea. Therefore, the significant focus on urea as the primary waste product highlights its essential role in the urinary system's function and the body's overall metabolic processes. This understanding is fundamental in comprehending kidney function and the handling of nitrogenous wastes in the body.