At the end of 2019 world's population was tested by presence Covid-19 virus, which in a short time classified as pandemic World Health Organization (WHO). Millions people have been affected infection and also tens thousands died. One preventions transmission virus is implementing culture clean living strict health protocols. Meanwhile, fact that implementation awareness protocols still low. The...

This article has summarized parts of certain publica­tions about changes of hematopoietic elements, specially erythroid, during embryonic and fetal to the third postnatal life. The main purpose of this article is to familiarize medical students with the physiological characteristics of the blood system, chiefly in the first trimenon of postnatal life.  It is also aimed to prevent many incorrec...