Pathology of the Hematopoietic System Pt 1 Flashcards
What are the primary lymphoid organs?
Thymus
Bursa
Peyers patches
Bone Marrow
What are the secondary lymphoid organs?
Tonsils
Spleen
Lymph nodes
Peyers patches
Bone Marrow
What occurs in the primary lymphoid organs?
Lymphocyte development
What occurs in the secondary lymphoid organs?
Lymphocyte antigen response site
What are the sources of lymphocytes and how that changes as time goes on?
Yolk Sac -> fetal liver -> bone marrow
What is the routes of lymphocytes from development to antigen response?
Source ( yolk, fetal liver, bone marrow ) -> Primary lymphoid organs -> secondary lymphoid organs
Where does hematopoiesis occur? Is that the same throughout life? What changes as the animal ages? What bones in adults?
- The composition of the marrow changes with age.
- Hematopoiesis occurs throughout flat and long bones.
- Hematopoietic tissue (red marrow) regresses and is replaced with nonhematopoietic tissue, mainly fat (yellow marrow).
- In adults, hematopoiesis occurs primarily in the pelvis, sternum, ribs, vertebrae, and proximal humerus and femur.
What is erythropoiesis? What stimulates it?
- Erythropoietin (Epo) regulates production of RBCs
- Release of Epo stimulated by hypoxia
- Other stimulators: ILs, CSFs, hormones
What is the stages of RBC development?
What are myeloid cells?
Granulocytic and monocytic cells are referred to collectively as myeloid cells.
What is the function of neutrophils and monocyte derived macrophages?
Neutrophils and monocyte-derived macrophages: phagocytosis and microbicidal activity
What is the function of eosinophils and basophils?
- Eosinophils and basophils: parasiticidal activity, allergic reactions
What is the function of macrophages?
Macrophages: antigen processing and presentation, and cytokine production
What are the stimulators of granulopoiesis and monocytopoiesis?
- Stimulators of granulopoiesis and monocytopoiesis
- Interleukins (ILs)
- Granulocyte colony-stimulating factor (G-CSF) and GM (granulocyte-macrophage)-CSF
What regulates thrombopoiesis? What is another name for this?
- Thrombopoietin (Tpo), synthesized primarily in the liver, regulates thrombopoiesis.
- Megakaryopoiesis
What are the stages of megakaryopoiesis?
What other cells can be found in the bone marrow?
- Lymphocytes (1-10%)
- Plasma cells (<1%)
- Stromal cells: reticular cells, adventitial cells, adipocytes * Osteoblasts, osteoclasts
When should you submit bone marrow aspirates/ core biopsies? What should you submit at the same time?
When?
* Any abnormal hematology finding such as:
* Unexplained cytopenias (any non-regenerative anemia)
* Maturation defects or morphologic abnormalities in blood cells * Potential myeloproliferative/ lymphoproliferative disease
* Potential malignancies metastatic to the bone marrow
- Must submit a concurrent CBC!
How do you obtain bone marrow aspirates and core biopsies?
How?
* Located in multiple sites but responds as a single tissue
* Samples can be taken from any bone with red marrow:
* Proximal femur, iliac crest, proximal humerus of dogs and cats * Sternum of horses
* Proximal rib of cattle
* Aspirates and core biopsies
What is the diagnostic occurring in this image?
bone marrow aspirates and core biopsies
What is the importance of bone marrow aspirates/ smears?
- Interpreted by clinical pathologists
Important for: - Cellular morphology and maturation
- Erythroid to myeloid ratio (M:E ratio)
- Primary or metastatic neoplasia
What is the importance of bone marrow core biopsies?
- Interpreted by anatomic pathologists
Important for: - Ratio of fat to hematopoietic cells
- Erythroid to myeloid ratio (M:E ratio)
- Adequacy of iron
- Stromal elements (e.g. for myelofibrosis)
- Primary or metastatic neoplasia
What diagnostic is seen here?
Bone marrow aspirate/smears