In the human embryo, the first site of blood formation is the yolk sac. Later in embryonic life, the liver becomes the most important red blood cell-forming organ, but it is soon succeeded by the bone marrow, which in adult life is the only source of both red blood cells and the granulocytes. Their job is to transport oxygen to the body's tissues in exchange for carbon dioxide, which is carried to and eliminated by the lungs. Red blood cells are formed in the red bone marrow of bones. Stem cells in the red bone marrow called hemocytoblasts give rise to all of the formed elements in blood. Erythroid (red blood) cells are the first cell type to be specified in the postimplantation mammalian embryo and serve highly specialized, essential functions throughout gestation and postnatal life. The existence of 2 developmentally and morphologically distinct erythroid lineages, primitive (embryonic) and definitive (adult), was described for the mammalian embryo more than a century ago. Cells of the primitive erythroid lineage support the transition from rapidly growing embryo to fetus, whereas definitive erythrocytes function during the transition from fetal life to birth and continue to be crucial for a variety of normal physiologic processes. Over the past few years, it has become apparent that the ontogeny and maturation of these lineages are more complex than previously appreciated. In this review, we highlight some common and distinguishing features of the red blood cell lineages and summarize advances in our understanding of how these cells develop and differentiate throughout mammalian ontogeny.
The best way to do that is to cook the amount of food that you know you SHOULD eat, not how much you WANT to eat.
If you don't cook more food than you should eat, then you can't eat more than you should.
Answer:
By accepting others' differences and not bullying
Respect the opinions of others
Answer:
well the person with cancer asked for X-RAY and then later complained so it's the patient is to blame
