Haemapoiesis

Question 1

What are the precursors of haematopoietic stem cells from which all blood is produced?

Answer 1

Haemangioblast

Question 2

Where are haemangioblasts derived from?

Answer 2

From the aortic/gonadal/mesonephros region of mesoderm in embryonic stage

Question 3

Where do haemangioblasts migrate to?

Answer 3

Yolk sac
Liver
Bone

Question 4

What are the name for the stem cells which reside in bone marrow and other haemapoietic tissue?

Answer 4

(Pluripotent) haematopoietic stem cells

Question 5

What are haematopoietic stem cells?

Answer 5

Common precursor cell of all blood cells

Question 6

How do haematopoietic stem cells differentiate into other blood cells?

Answer 6

Driven by growth factors

Question 7

What two types of cell do haematopoietic stem cells differentiate into?

Answer 7

Lymphoid progenitor (multipotent) cells
Myeloid progenitor (multipotent) cells

Question 8

Which cells are lymphoid progenitor cells responsible for producing?

Answer 8

B cells (mature in bone marrow)
T cells (mature in thymus)
NK cells (mature in bone marrow)

Question 9

Which cells are myeloid progenitor cells responsible for producing?

Answer 9

RBCs
Platelets
Monocytes, Macrophages, Neutrophils
Eosinophils
Basophils

(mature in bone marrow)

Question 10

Which growth factor is responsible for increasing stem cell production?

Answer 10

Stem cell factor

Question 11

Which growth factor is responsible for increasing myeloid progenitor cell production?

Answer 11

Interleukin 3

Question 12

Which growth factor is responsible for increasing monocyte and granulocyte production?

Answer 12

G-MCSF (Granulocyte-Monocyte Colony Stimulating Factor)

Question 13

What is the role of Erythropoeitin?

Answer 13

Accelerates production of Erythrocytes (RBCs)

- produced in response to low pO2

Question 14

What is the role of Thrombopoeitin?

Answer 14

Accelerates production of megakaryocytes => platelets

Question 15

What is the role of G-CSF?

Answer 15

Accelerates production and maturation of neutrophils

Question 16

Where are the sites of haematopoiesis in the foetus?

Answer 16

Up to 3 months = yolk sac
3 to 6 months = liver and spleen
6 months onwards = bone marrow

Question 17

Where are the sites of haematopoiesis in children?

Answer 17

Bone marrow

- long bones as well as central bones initially important, although become less so as grow older

Question 18

Where are the sites of haematopoiesis in adults?

Answer 18

Bone marrow of ribs, sternum, vertebrae and pelvis

• Long bones, spleen and liver in tmes of great demand or leukaemia

Question 19

What does the bone marrow space consist of?

Answer 19

Bone trabeculae, with osteoblasts, osteoclasts, and osteocytes

Collagen

Fat spaces

Arterioles, sinusoids, and venules

Haematopoietic stem cells (at various development stages)

Question 20

What is bone marrow aspiration?

Answer 20

Uses fine needle to draw out contents as fluid

- allows examination of cells rations and level of maturation

Question 21

What is a bone marrow biopsy?

Answer 21

Small, 1-2mm bored which colelcts core of bone marrow to allow examination of bone marrow architecture

Shows: hypo or hypercellularity