3. Bone marrow 2024

Bone Marrow

The tissue enclosed by cortical and cancellous bone; consists mostly of hematopoietic cells, adipose tissue, and supportive tissue.

Red Bone Marrow

Involves hematopoiesis; all bone marrow is red early in life and becomes yellow as mammals age.

Yellow Bone Marrow

Mainly fatty tissue with no hematopoietic function; can become red in certain conditions.

Hematopoietic Cells

Precursors to hemic cells found in blood or tissue, which include cells in the mitotic and post-mitotic pools.

Aspirate vs Biopsy

Aspirate is performed more frequently and is easier and faster; a biopsy involves a core sample and provides more accurate evaluation.

Common Sites for Bone Marrow Aspiration in Dogs

Proximal humerus, trochanteric fossa of the proximal femur, iliac crest.

Stem Cell Disorders of Marrow

Conditions involving reversible or irreversible injuries to stem cells that affect hematopoiesis.

Erythropoiesis

The process of red blood cell production from stem cells to mature erythrocytes.

Granulocytes

White blood cells characterized by the presence of granules in their cytoplasm, including neutrophils, eosinophils, and basophils.

Megakaryocyte Series

Large multinucleated cells in the marrow from which platelets are formed.

Myelofibrosis

Increased fibrous connective tissue & collagen within the bone marrow, affecting hematopoiesis.

Acute Leukemia

Neoplastic proliferation of hematopoietic cells leading to rapid disease progression and poor outcomes without treatment.

Chronic Leukemia

Characterized by partial maturation of malignant cells, leading to a more indolent course and longer survival.

EPO (Erythropoietin)

A hormone produced mostly by the adult kidney in response to hypoxia, stimulating red blood cell production.

Aspirate Technique

Involves the removal of the stylet, then attaching a syringe and applying negative pressure to obtain marrow.

Slide Preparation for Bone Marrow Analysis

Smears must be prepared quickly; air-dried and stained with Romanowsky stain for examination.