Glucose is not normally found in the urine because it a. does not pass through the walls of the glomerulus, b. is kept in the blood by colloid osmotic pressure, c. is reabsorbed by the tubule cells, d. is removed by the body cells before the blood reaches the kidney.

Verified step by step guidance

1. Understand that glucose is a small molecule that can pass through the walls of the glomerulus during filtration.
2. Recognize that under normal conditions, glucose is reabsorbed in the proximal convoluted tubule of the nephron.
3. Consider the role of the tubule cells in actively transporting glucose back into the bloodstream, preventing it from being excreted in urine.
4. Eliminate options that do not align with the physiological process of glucose reabsorption, such as options related to osmotic pressure or removal by body cells before reaching the kidney.
5. Conclude that the correct reason glucose is not normally found in urine is due to its reabsorption by the tubule cells.

Key Concepts

Glomerular Filtration

Glomerular filtration is the process by which blood is filtered in the kidneys, specifically in the glomeruli. During this process, small molecules, including glucose, can pass through the glomerular membrane into the renal tubules. However, glucose is typically reabsorbed later in the nephron, preventing its presence in urine under normal conditions.

Tubular Reabsorption

Tubular reabsorption is the process by which the kidneys reclaim water, ions, and nutrients from the filtrate back into the bloodstream. In the case of glucose, it is actively reabsorbed in the proximal convoluted tubule through specific transporters, ensuring that it is not lost in urine. This mechanism is crucial for maintaining glucose homeostasis in the body.

Colloid Osmotic Pressure

Colloid osmotic pressure refers to the pressure exerted by proteins in the blood plasma that helps retain water within the circulatory system. While it plays a role in fluid balance, it is not the primary mechanism for glucose retention. Instead, glucose levels in urine are primarily regulated by filtration and reabsorption processes in the kidneys.