Hematopoiesis - Bone Marrow Flashcards
Describe myeloid tissue
Where hematopoiesis begins and completes (for all formed elements except lymphocytes).
Describe lymphoid tissues
Tissues with lymphocytes.
Primary: Sites of antigen-independent lymphocyte generation. (B cells = bone marrow; T cells = bone marrow and eventually thymus).
Secondary: Where adaptive immune responses are initiated. (MALT, GALT, BALT, CALT = mucosa-, gut-, bronchus, and conjunctiva-associated lymphoid tissue).
Describe process of RBC renewal including turnover time, ingestion, and the fate of globin, iron, and heme
Turnover rate: Every 120 days.
Ingestion: By macrophages of spleen, bone marrow, liver.
Globin fate: Hydrolyzed into amino acids and excreted by kidneys in urine.
Iron fate: Reused by body.
Heme fate: Degraded to bilirubin, transported to liver, excreted in bile via gallbladder.
Compare changes in hematopoietic tissue throughout life
0-3mos gestation: Yolk sac.
After 7wks: LIver takes over until week 24.
After 9wks: Also seen in thymus.
10-11wks: Hematopoietic cells first seen in red bone marrow. Becomes primary site during infancy and continues during adulthood.
Adults: Most red bone marrow becomes fatty yellow marrow (no hematopoiesis). Red bone marrow remains in skull, vertebrae, ribs, sternum, ilia, and proximal epiphyses of long bones.
Describe characteristics of pluripotential stem cells including self-renewal status, differentiation, mitotic activity, and location
Self-renewal: Yes.
Differentiation: Can differentiate into almost any cell.
Mitotic activity: Low.
Location: Few in bone marrow, fewer in blood.
Describe characteristics of multi-potential stem cells including self-renewal status, differentiation, mitotic activity, and location
Self-renewal: Yes.
Differentiation: Many cells; less than pluripotent.
Mitotic activity: Low.
Location: Few in bone marrow, fewer in blood.
Describe characteristics of progenitor cells including self-renewal status, differentiation, mitotic activity, location, and function
Self-renewal: Yes. Differentiation: Mono- or bi-potential. Mitotic activity: High. Location: Bone marrow to secondary lympoid tissue where they proliferate. Function: None.
Describe characteristics of precursor cells including self-renewal status, differentiation, mitotic activity, and function
Self-renewal: No.
Differentiation: Mono-potential.
Mitotic activity: High.
Function: Specific morphology and function.
Define importance of colony forming units
Allows quantification of number of stem cells.
Name stem cell, progenitor, and precursor for blood cells and platelets: Erythrocytes
Stem cell: Myeloid
Progenitor: CFU-E(rythrocyte)
Precursor: Reticulocyte
Name stem cell, progenitor, and precursor for blood cells and platelets: Neutrophils
Stem cell: Myeloid
Progenitor: CFU-GM (granulo-monocyte)
Precursor: Neutrophilic metamyelocyte
Name stem cell, progenitor, and precursor for blood cells and platelets: Lymphocytes
Stem cell: Lymphoid
Progenitor: B or T lymphoblast
Precursor: Prolymphocyte
Name stem cell, progenitor, and precursor for blood cells and platelets: Monocytes
Stem cell: Myeloid
Progenitor: CFU-GM (granulo-monocyte)
Precursor: Promonocyte
Name stem cell, progenitor, and precursor for blood cells and platelets: Eosinophils
Stem cell: Myeloid
Progenitor: CFU-GM (granulo-monocyte)
Precursor: Eosinophilic metamyelocyte
Name stem cell, progenitor, and precursor for blood cells and platelets: Basophils
Stem cell: Myeloid
Progenitor: CFU-GM (granulo-monocyte)
Precursor: Basophilic metamyelocyte
