What substances are typically reabsorbed in the nephron?

The substances typically reabsorbed in the nephron are water, glucose, amino acids, and essential ions.

In the nephron, the functional unit of the kidney, several substances are reabsorbed to maintain the body's homeostasis. The process of reabsorption primarily occurs in the proximal convoluted tubule, the loop of Henle, and the distal convoluted tubule.

The proximal convoluted tubule is responsible for the reabsorption of about 65% of the filtered water, glucose, and amino acids. This is facilitated by active transport mechanisms. Glucose and amino acids are reabsorbed completely, ensuring that these vital nutrients are not lost in the urine. Sodium ions are also reabsorbed here, which helps to maintain the body's salt and water balance.

The loop of Henle plays a crucial role in the reabsorption of water and ions, particularly sodium and chloride ions. The descending limb of the loop is permeable to water but not to ions, allowing water to be reabsorbed back into the bloodstream. The ascending limb, on the other hand, is impermeable to water but permeable to ions, facilitating the reabsorption of sodium and chloride ions.

The distal convoluted tubule and the collecting duct are the final sites of reabsorption. Here, fine adjustments are made to the concentrations of various ions, including potassium, sodium, and calcium, and to the volume of water reabsorbed, under the control of various hormones. This ensures that the final urine excreted has the correct balance of water and solutes.

In summary, the nephron reabsorbs water, glucose, amino acids, and essential ions to maintain the body's homeostasis. This process is crucial for the body's overall health and functioning.