ERYTHROPOIESIS FOR THE USMLE EXAMS
– Begins in the yolk sac at 4mnth of gestation
– At 6 months of gestation, it moves into the liver, flat bones, and the spleen.
– At 8 mnth of gestation, it moves into the long bones.
* a child with sickle cell before 1yr of age, you’ll see their head enlarge, spleen get big, etc
** if you ever lose your long bones, the spleen will take over and you’ll get massive splenomegaly.
*** If you ever see someone with massivesplenomegaly, always think of problems that eliminate bone marrow production (vinblastine, chloramphenicol, AZT, benzene)
Virus that can wipe out BM –> parvo B19
Bone disease wiping out BM –> osteopetrosis (decreased osteoclastic activity – no bone broken down, obliterates BM).