Manitoba Nephrology Nurse Practice Test

Which of the following substances is mainly filtered in the glomerulus?

1. Only proteins

2. Only water

3. Only electrolytes

4. Electrolytes, water, and waste products

The correct answer is: Electrolytes, water, and waste products

The correct choice highlights that the glomerulus is responsible for filtering a variety of substances, specifically electrolytes, water, and waste products. The glomerulus, a key component of the nephron in the kidneys, operates on the principle of ultrafiltration. During this process, blood pressure drives the movement of fluid through the glomerular capillaries, allowing small molecules and waste products to pass through the filtration barrier into the Bowman's capsule. Electrolytes such as sodium, potassium, and chloride, along with water, are freely filtered due to their small size and solubility. Waste products, including urea and creatinine, are also filtered as they are byproducts of metabolism. This filtration is essential for maintaining homeostasis and facilitating the formation of urine while retaining larger molecules, especially proteins, which are typically too large to be filtered and remain in the bloodstream. Understanding this filtration mechanism is crucial for nephrology, as it impacts processes such as fluid and electrolyte balance in the body, affecting overall kidney function and health.