Question

In the Foetus, erythropoiesis starts in
A. Spleen
B. Red bone marrow
C. Kidney
D. Liver

Answer 1

Hint: Erythropoiesis: It is the process of producing red blood cells or erythrocytes which is the developed from erythropoietic stem cell and mature into red blood cell.
The stages of erytropoiesis are:
1. Hemocytoblast
2. Proerythroblast
3. Early, intermediate and late normoblast
4. Reticulocyte
5. Erythrocyte

Complete answer:
- Haemopoiesis: It is the development of blood cells that are RBCs, WBCs and platelets.
So, the term haemopoiesis includes:
- Erythropoiesis: It means development of RBCs.
- Leucopoiesis: It means development of WBCs.
- Megakaryocytopoiesis: It is the development of platelets.
So, according to the question, erytropoiesis as we known is the development of RBCs or red blood cells.

During Intrauterine life, erytropoiesis occurs in three stages:
- Mesoblastic stage: In early embryo up to 3 months of foetal life, RBCs are formed from mesoderm of yolk sac.
- Hepatic Stage: After 3 months of foetal life, liver and spleen is the site of blood formation.
- Myeloid Stage: In the middle of foetal life, erythropoiesis occurs in the bone marrow.
Hepatic and myeloid stages are extra vascular erythropoiesis.

In children, erythropoiesis occurs in:
- All bones with red marrow mainly
- Liver
- Spleen

In Adults, after 18-20 years of age from red bone marrow this includes:
- Ends of long bones.
- Skull
- Ribs
- Sternum
- Pelvis
So, according to the question in the early foetus, erythropoiesis takes place in the mesoderm cells of the yolk sac.

By the third or fourth month, erythropoiesis moves to the liver. After seven months, erythropoiesis occurs in the bone marrow.

Hence, the correct answer is option (D).

Note: Anaemia is the clinical condition characterized by reduction in the number of RBCs less than 4 million or their content of haemoglobin is less than 12 g or both.
Anaemia can be of different types:
- Iron deficiency anemia
- Megaloblastic anaemia
- Sideroblastic anaemia
- Pernicious anaemia
- Thalasemia