Hematopoiesis

Hematopoiesis starts at around what day of embryonic development

19th

Identify the theory the origin of hematopoietic progenitor cells:

• each blood cell lineage is derived from its own unique stem cell

Polyphyletic theory

Identify the theory the origin of hematopoietic progenitor cells:

• all blood cells are derived from a single progenitor stem cell; pluripotent stem cell

Monophyletic theory

Identify the theory the origin of hematopoietic progenitor cells:

• most widely accepted theory among experimental hematologists

Monophyletic theory

Three phases of hematopoiesis

1. Mesoblastic/Megaloblastic

2. Hepatic

3. Intramedullary/Medullary/Myeloid

Chief site of hematopoiesis for: Mesoblastic

Yolk sac

Chief site of hematopoiesis for: Hepatic phase

Fetal liver

Besides the fetal liver, what other organs may contribute to hematopoiesis

• Spleen

• Thymus

• Lymph nodes

Chief site of hematopoiesis for: Medullary

Bone marrow

Identify the phase of hematopoiesis:

• Primitive erythroblasts

Mesoblastic phase

1st blood cells to be formed

Primitive erythroblasts

Hemoglobin found in Mesoblastic phase

• Gower-1

• Gower-2

• Portland

First fully developed organ in the fetus

Thymus

Where are B cells produced in Hepatic phase

Kidneys and spleen

What month does hematopoiesis start in the bone marrow

5th month of fetal development

TRUE OR FALSE: Only the BM participate in hematopoiesis in adults

FALSE; also lymph nodes, spleen, thymus, and liver

Process of replacing red marrow by yellow marrow during development

Retrogression

Retrogression happens when

5 - 7 years of age

Red marrow is restricted to what sites

RSVP

• Ribs

• Sternum, Skull, Shoulder blades

• Vertebrae

• Pelvis, Proximal ends of long bones

Primary lymphoid organs

BM and Thymus

Major secondary lymphoid organs

Spleen and lymph nodes

Major organ in the body in which antibodies are synthesized and from which they are released into the circulation

Spleen

Solid tumor neoplasm of lymphoid tissue

Lymphoma

These are clusters of lymphocytes distributed in the lining of the small intestine; detect substances that diffuse across the intestinal epithelium

Peyer’s patches

Organ that can participate in hematopoiesis only as a response to infectious agents or in pathologic myelofibrosis of the BM

Liver

Process where blood cells are produced from the liver

Extramedullary hematopoiesis

Preferred sires for BM aspiration in ADULTS

Posterior superior iliac crest

Anterior superior iliac crest

Preferred sure for BM aspiration in children less than 2 years old

Anterior medial surface of the TIBIA

Normal M:E ratio

1.5:1 to 3.3:1

In marrow differential, how many cells needed to count

At least 500; preferably 1000 on each of 2 slides

BM smears should be retained for how long

10 years

2 organs where Extrameduallary hematopoiesis MAINLY occurs

Liver and spleen

RBC maturation phases

PB PORE

• Pronormoblast

• Basophilic normoblast

• Polychromatophilic normoblast

• Orthochromic normoblast

• Reticulocyte

• Erythrocyte

Identify the RBC maturation stage:

• dark blue due to presence of RNA and ribosomes

Pronormoblast

Identify the RBC maturation stage:

• richer blue

• Detectable Hgb synthesis

Basophilic normoblast

Identify the RBC maturation stage:

• 1st stage associated with pink color due to Hgb

Polychromatophilic normoblast

Identify the RBC maturation stage:

• not capable of division

Orthochromic normoblast

Reticulocytes stay in the BM for how many days

1-2 days

Reitculocytes stay in the PB for how many days

1 day

WBC maturation stages for Neutrophils

1. Myeloblast

2. Promyelocyte

3. Myelocyte

4. Metamyelocyte

5. Band

6. Segmented neutrophil

As WBCs mature, their cell size increases or decreases

Decreases

As WBC matures, the nuclear-cytoplasmic ratio increases or decreases

Decreases

As WBC matures, chromatin becomes more or less condensed

More condensed

How much does the central pallor take up in RBCs

1/3

Chromosome associated with EPO

Chromosome 7

Label that may be used to attach to RBCs to check for RBC survival

Chromium-51

Earliest marker of erythroid differentiation; transferrin receptor

CD71

Primary cell source of EPO

Peritubular interstitial cell of the kidneys