Estructura E Médula Ósea (Inglés)

BONE MARROW STRUCTURE AND DIAGNOSTIC TESTING
I. Bone Marrow Structure

A. Overview
Bone marrow is a semi-solid gelatinous tissue which resides within the bony cavities os the axial skeleton. Itcontains hematopoietic cells (red marrow), stromal cells, and fat (yellow Marrow).
B. Bone
The bone that surrounds the marrow is composed of a thick layer of compact bony material referred to ascortical bon. This bone is covered by fibrocartilaginous tissue (periosteum). The space inside cortical bone is called the medullary cavity. The medullary cavity itself contains a lattice-like network ofthin bone referred to as trabecular or cancellous bone. Hematopoietic cells reside in the intervening spaces of trabecular bone.

1. Structure Bone
(a) Woven bone tissue in which the normalparallel fibrillar structure of the bone as not been fully created. It is the pattern seen in newly formed bone.
(b) Lamellar bone is mature bone in which there is a microscopically visible parallelstructure referred to as cement lines.
2. Cellular components of bone
(a) Osteoblasts
(i) Osteoblasts are bone forming cells of mesenchymal origin that synthetize glycosaminoglycanes and collagen fibers(osteoid or non-mineralizaed bone) forming the basis of bone structure.
(ii) In tissue biopsy sections the cells are flat to slightly rounded and line the bony trabeculae and cortical boneparticularly in areas of new bone formation
(iii) On aspirate smears the cells resemble plasma cells although the nucleus appears to be falling out of the cell. The cells commonly occur in small loosecollections.
(iv) Osteoblasts are not generally encountred in bone marrow aspirated from normal adults but may be seen in growing children, sites of bony injury, or hyperparathyroidism.
(b) Osteoclasts
(i)Osteoclasts are bone resorbing/ remodeling multinucleated cells derived from the monocyte/ macrophage lineage.
(ii) The cells reside in scooped out areas of trabecular bone referred to as Howship’s...