Tubular reabsorption

Definition

Tubular reabsorption is the process by which the kidneys reclaim water, electrolytes, and nutrients from the tubular fluid back into the bloodstream. It occurs primarily in the proximal convoluted tubule, loop of Henle, distal convoluted tubule, and collecting duct.

5 Must Know Facts For Your Next Test

1. Approximately 99% of the filtrate is reabsorbed during tubular reabsorption.
2. Glucose, amino acids, and ions like sodium and chloride are actively transported during this process.
3. Water reabsorption can be either obligatory or facultative; it is regulated by hormones such as antidiuretic hormone (ADH).
4. Tubular reabsorption helps maintain homeostasis by regulating blood volume and composition.
5. The proximal convoluted tubule is responsible for the majority of reabsorption.

Review Questions

• What percentage of filtrate is typically reabsorbed during tubular reabsorption?
• Which part of the nephron performs the most significant amount of tubular reabsorption?
• How do hormones like ADH affect water reabsorption in the kidneys?

Related terms

Glomerular Filtration: The initial process in urine formation where blood plasma is filtered through the glomerulus into Bowman's capsule.

Proximal Convoluted Tubule: A segment of the nephron that primarily handles bulk reabsorption of solutes and water from filtrate.

Antidiuretic Hormone (ADH): A hormone that increases water permeability in kidney's collecting ducts to facilitate more water reabsorption.