Lecture 17: Bone Marrow + Hematopoiesis

Question 1

Sites of hematopoiesis

Answer 1

• Yolk sac
• Liver/spleen
• Bone marrow (red marrow)

Question 2

Blood sequestration sites

Answer 2

• Macrophages are stored in the spleen as monocytes
• Neutrophils stored in marginated pools attached to endothelium
• Lymphocytes stored in secondary lymphatic organs

Question 3

Vasculogenesis

Answer 3

Vessel creation out from CT; MET of lateral splanchnic mesoderm to endothelium.

Question 4

Angiogenesis

Answer 4

Growth/sprouting of vessels from existing ones; tip cells direct stalk cell formation into vascular lumens.

Question 5

First hematopoietic site

Answer 5

Extraembryonic mesoderm (yolk sac) forms early endothelium (MET) and blood islands

Question 6

Bone marrow compartments

Answer 6

1. Vascular compartment
2. Hematopoietic (CT)

Question 7

Vascular bone marrow compartment

Answer 7

Vascular sinus, containing large sinusoidal capillaries

Question 8

Hematopoietic (CT) compartment of bone marrow

Answer 8

Contains stroma (supporting) and parenchyma (functional). Stroma has MSC and HSC (Ocls, macrophages) components

Question 9

Eosinophilic granule structure in EM

Answer 9

Ovoid with internum + externum

Question 10

Basophilic granule structure in EM

Answer 10

Large and distinct e.g. heparin, histamine

Question 11

Endomitosis

Answer 11

DNA replication without cell division; process by which promegakaryocytes become polyploid and develop into mature megakaryocytes

Question 12

Leukemia categorization

Answer 12

A/C = acute/chronic
M/L = myelogenous/lymphocytic
L = leukemia