PHGY 209 Lecture Notes - Lecture 8: Erythropoietin, Macrophage, Globin
21 Feb 2018
School
Department
Course
Professor
Document Summary
Erythropoietin does not act on the pluripotent stem cell; it acts only on the committed cell to stimulate the division and maturation of the committed stem cell (red cell precursors). Thus, males have a higher number of rbc. Decrease sensitivity of rbc precursors to erythropoietin. The rate of rbc synthesis is also very quick: 1% of rbc are newly released every day. During that time, each rbc travels the equivalent of 300 miles due to constant circulation. Nothing prolongs rbc lifespan; however, there are many substances that decrease it. Old rbcs are recognized as such and are removed from the circulation by a system of highly phagocytic cells known as macrophages. This can be denoted by a more fragile or disrupted membrane caused by the constant travel through narrow capillaries; possible surface markers. Macrophages are highly phagocytic cells which can recognize no longer functional rbcs.
