Erythropoiesis - Areas of RBC production

Question 1

In the early weeks of embryonic life, in what form are RBCs produced? Where does this occur?

Answer 1

As primitive nucleated RBCs.

In the yolk sac.

Question 2

What is the main organ which produces RBC during the middle trimester of gestation? Name the other organs in which they’re also produced.

Answer 2

Liver.

Spleen and lymph nodes

Question 3

What is the exclusive site of RBC production during the last month or so of gestation and after birth?

Answer 3

Bone marrow

Question 4

Until what age do all the bones in a person’s body produce RBCs?

Answer 4

5 years of age

Question 5

What changes occur in the marrow of the long-bones after the age of 20 years? In which sites does this not occur?

Answer 5

The marrow becomes fatty and stops producing RBCs.
Except in proximal portions of the humeri and tibiae.

(Figure 33-1)

Question 6

Beyond the age of 20 years, what are the main sites of RBC production?

Answer 6

Most ABCs are produced in the marrow of membranous bones such as the vertebrae, sternum, ribs and ilia.

(Figure 33-1)

Question 7

As age increases, what happens to the productivity of the bone marrow?

Answer 7

Decreases