What are examples if substances that reabsorbed into the blood?

Several substances are reabsorbed into the blood as substances pass through the nephron. Some examples include:

- Water: The majority of water filtered from the renal corpuscle is reabsorbed by the nephrons. Active transport of sodium ions creates an osmotic gradient that drives the reabsorption of water.

- Glucose: Glucose is actively transported from the tubules back to the blood stream. Most glucose filtered by the nephron is reabsorbed in the proximal convoluted tubule (PCT), with the SGLT2 transporter playing a significant role in this process.

- Amino acids: Amino acids are actively reabsorbed by specialized proteins in the tubular cells. Different types of amino acids have specific transport systems.

- Sodium ions (Na+): Sodium ions are actively transported out of the tubules into the interstitial fluid, primarily in the PCT. The sodium-potassium pump on the basolateral membrane of tubular cells uses energy to exchange Na+ for K+.

- Chloride ions (Cl-): Chloride ions generally follow the movement of sodium ions due to electrical and osmotic gradients created by sodium reabsorption.

- Bicarbonate ions (HCO3-): Bicarbonate ions are reabsorbed in the proximal tubule and the collecting ducts. The process involves the exchange of H+ ions for Na+ ions and the combination of H+ ions with HCO3- to form carbonic acid.

These substances, along with various other ions and molecules, are reabsorbed to maintain the body's electrolyte balance, fluid volume, pH, and overall homeostasis.