resorption

Resorption is the process by which substances are removed, dissolved, or absorbed into a cell, tissue, or organism, typically involving breakdown and subsequent uptake of material. It can refer to mineralized tissue resorption, cellular reuptake of substances, or the retrieval of nutrients from older tissues.

In bone biology, resorption is carried out by osteoclasts that dissolve bone mineral and degrade organic matrix, releasing calcium and phosphate into the bloodstream. This occurs during bone remodeling and calcium homeostasis and is balanced by formation by osteoblasts.

Dental resorption involves loss of tooth structure due to cellular activity. External root resorption occurs along the external tooth surface, while internal resorption begins within the pulp canal; causes include trauma, inflammation, or orthodontic forces.

In the kidneys and intestines, resorption refers to reabsorption of substances from filtrate or gut contents: the proximal tubule reabsorbs water, glucose, amino acids, and electrolytes; the small intestine reabsorbs nutrients and minerals.

In botany, resorption describes the retrieval of nutrients from aging leaves into developing tissues or seeds, mediated by phloem transport.

Understanding resorption is important in medicine and agriculture, because excessive or deficient resorption underlies conditions such as osteoporosis, dental resorption, and nutrient-wasting diseases.