GLOSSARY

Renal Erythropoietin-Producing Cells
Renal interstitial fibroblast-like cells produce EPO in response to oxygen-related sensing.

Volume, blood cells and iron

Renal and cardiovascular signals regulate circulation and sodium handling, while EPO, thrombopoietin and iron-regulatory hormones support blood-cell production. These pathways interact but have different sources, receptors and response times.

Interpreting the mechanism

Kidney injury can impair this response and contribute to anemia.

An exercise distinction

A rapid change in plasma volume can alter measured blood concentrations before new blood cells are produced. Endocrine stimulation, iron availability and marrow response determine longer-term erythropoiesis. A single post-exercise result cannot independently establish increased oxygen-carrying mass.