What happens to molecules like glucose, amino acids, vitamins, minerals, and bicarbonate ions in the nephron?
Kidney Reabsorption Once inside the lumen of the nephron, small molecules, such as ions, glucose and amino acids, get reabsorbed from the filtrate: Specialized proteins called transporters are located on the membranes of the various cells of the nephron. These transporters grab the small molecules from the filtrate as it flows by them. Each transporter grabs only one or two types of molecules. For example, glucose is reabsorbed by a transporter that also grabs sodium. Transporters are concentrated in different parts of the nephron. For example, most of the Na transporters are located in the proximal tubule, while fewer ones are spread out through other segments. Some transporters require energy, usually in the form of adenosine triphosphate (active transport), while others don’t (passive transport). Water gets reabsorbed passively by osmosis in response to the buildup of reabsorbed Na in spaces between the cells that form the walls of the nephron. Other molecules get reabsorbed passive
