Question

What is absorbed/secreted throughout the nephron/peritubular capillaries?

Answer 1

In the nephron, the process of filtration occurs in the glomerulus, where water, ions, and small molecules such as glucose and amino acids are filtered from the blood into the Bowman's capsule. From there, the filtrate moves through the proximal tubule, where some substances are reabsorbed into the peritubular capillaries, such as glucose and amino acids.

As the filtrate moves through the loop of Henle, water and ions are reabsorbed and/or secreted, depending on the specific segment of the loop. In the distal tubule, more ions are secreted into the filtrate, and some substances that were not filtered out in the glomerulus are reabsorbed. Finally, in the collecting duct, water is reabsorbed, and the resulting urine is excreted from the body.

Answer 2

The nephron is the functional unit of the kidney responsible for filtering blood and forming urine. It consists of several segments, each with specific functions in the process of urine formation. Peritubular capillaries are a network of small blood vessels that surround the nephron tubules and play a crucial role in reabsorption and secretion.

Here's a summary of the major substances that are absorbed or secreted at different segments of the nephron and peritubular capillaries:

Glomerulus: The glomerulus is the initial part of the nephron where blood is filtered. Filtration here allows water, ions (e.g., sodium, potassium, calcium), glucose, amino acids, urea, and small molecules to pass from the blood into the glomerular filtrate.

Proximal Convoluted Tubule (PCT): In the PCT, most of the reabsorption occurs. Substances that are actively reabsorbed here include glucose, amino acids, vitamins, and the majority of the filtered bicarbonate, sodium, chloride, and water. Passive reabsorption of ions and water also occurs.

Loop of Henle: The descending limb of the loop of Henle is permeable to water but not to solutes. Water is reabsorbed here, which increases the concentration of the filtrate as it descends into the medulla.

Distal Convoluted Tubule (DCT): The DCT is responsible for fine-tuning the reabsorption and secretion processes. It actively secretes hydrogen ions and potassium ions into the tubule and reabsorbs sodium and water based on the body's needs and hormonal signals.

Collecting Duct: The collecting duct is the final segment where water reabsorption occurs, regulated by the hormone ADH (antidiuretic hormone). ADH makes the collecting duct permeable to water, allowing for water reabsorption and concentrating the urine.

Peritubular Capillaries: The peritubular capillaries surround the nephron tubules and are involved in reabsorbing substances that were filtered at the glomerulus and need to be returned to the bloodstream. They are also responsible for secreting certain substances into the tubules for excretion.

In summary, the nephron and peritubular capillaries work together to filter blood and form urine. Important substances like water, ions (e.g., sodium, potassium, calcium), glucose, amino acids, and urea are reabsorbed or secreted at different segments of the nephron and the peritubular capillaries to maintain the body's internal balance and eliminate waste products.

Step-by-step explanation:

Hope this helps.