Hematopoiesis

Question 1

Hematopoiesis

Answer 1

The production of blood cells, regulated by a variety of growth factors

Question 2

Pluripotential stem cells

Answer 2

Cells that give rise to myeloid and lymphoid cells, which are the origins of all blood cell types. No restriction on what kind of cells they differentiate into.

Question 3

Myeloid cells

Answer 3

Stem cells that are present in the bone marrow and give rise to the erythrocytes, granulocytes, monocytes, and thrombocytes (unipotential cells). They have multipotential lineages and are capable of self renewal.

Question 4

Unipotential (Restricted) progenitor cells

Answer 4

Stem cells that are restricted in what they can form (Erythrocytes, granulocytes, megakaryocytes, and monocytes).

They are stimulated by growth factors that include erythropoietin (EPO), the colony stimulating factors (CSF), thrombopoietin (TPO) and interleukins (IL).

Question 5

Thrombocytes

Answer 5

Fragments of megakaryocytes.

Question 6

Lymphoid stem cells

Answer 6

Stem cells with multipotential lineages and self renewable. They give rise to T or B lymphocytes.

Question 7

Developmental stages of hematopoiesis

Answer 7

1) Primordial Stage
2) Hepato-spleno-thymic stage
3) Medullo-lymphatic stage

Question 8

Primordial stage

Answer 8

Embryonic yolk sac produces large, nucleated RBC’s

Question 9

Hepta-spleno-thymic stage

Answer 9

Occurs mainly in the liver and some of the spleen during the 2nd trimester. Produces precursor granulocytes and megakaryocytes, as well as definitive erythroblasts.

Question 10

Medullo-lymphatic stage

Answer 10

Exclusive site of hematopoiesis in the bone marrow and lymph nodes during the 3rd trimester. Produces all cell types.

Question 11

Red bone marrow

Answer 11

Hematopoietically active site. Red tissue, highly vascular, source of nutrients, and fills the space of the trabeculae in the cancellous bone. Only source of hematopoiesis at birth and becomes limited in adults. It has a vascular & hemopoietic (extravascular) compartment with a bone endosteum outer shell. Its function is to produce RBCs, store iron, and develop B lymphocytes.

Question 12

Yellow bone marrow

Answer 12

marrow with large amounts of fat and connective tissue appears yellow

Question 13

T lymphocytes

Answer 13

Cellular immunity. Produced in red bone marrow, mature in the thymus.

Question 14

B lymphocytes

Answer 14

Humoral immunity. Produced and mature in the red bone marrow.

Question 15

Erythropoietin

Answer 15

stimulates the production and proliferation of erythroid progenitor cells

Question 16

Atrophy

Answer 16

Decrease in size of a tissue or organ. Ex/ Golgi are atrophic in the metamyelocyte stage.

Question 17

Thrombopoietin (TPO)

Answer 17

key hormone which regulates the maturation, size, and number of megakaryocytes; is produced in the liver, bone marrow, and other tissues