Animal Histology Exercise 6: Myeloid Tissue PDF

Biology Department College of Arts & Sciences BIOL 113 L – Animal Histology Prepared by L. Saab and P. Fudalan Exercise 6. MYELOID TISSUE (Bone Marrow) Myeloid tissue is a gelatinous, vascular, cell-ri...

Biology Department College of Arts & Sciences BIOL 113 L – Animal Histology Prepared by L. Saab and P. Fudalan Exercise 6. MYELOID TISSUE (Bone Marrow) Myeloid tissue is a gelatinous, vascular, cell-rich connective tissue. It occupies the cavities of long bones and intertrabecular spaces of spongy bones as bone marrow. It provides the microenvironment for the formation of blood cells and platelets (hematopoiesis). In infants and younger individuals, the bone marrow is actively producing blood cell precursors, blood cells in various stages of development but predominantly red blood cells, thus called red bone marrow. As the individual reaches about 20 years of age, much of the bone marrow in long bones accumulates so much fat and it becomes haematopoietically inactive, and called yellow bone marrow. The red bone marrow is composed of two compartments. The vascular compartment comprising of reticular tissue, blood vessels and sinusoids for nutrient supply and transport of newly formed blood cells. The other compartment is the hematopoietic islands (hematopoietic cords), each composed of progenitor cells, precursor cells and developing or maturing blood cells of specific lineage. Both compartments also contain macrophages, reticular cells, and fine mesh of reticular fibers. Activity 1. Red Bone Marrow The red bone marrow is haematopoietically active that fills the cavity of a long bone or the cavities of spongy bone. A. Examine the cross-section of the bone marrow (Plate 1) at high power objective. B. Distinguish the following: hematopoietic (hemopoietic) islands – clusters of hematopoietic cells stroma – the framework that is composed of all tissues that are indirectly involve in hematopoiesis. It consists of reticular connective tissues, and blood vessels (sinusoids). Stromal cells include macrophages, adipocytes, reticulocytes, osteoblasts, osteoclasts, and endothelial cells. bone trabeculae – eosinophilic struts projecting into hemopoietic islands C. Photograph a section of the red bone marrow and paste in appropriate section of Worksheet 5. D. Label the photomicrograph. Plate 1. Red bone marrow 1 This material is owned by Biology Department – Xavier University and it is for exclusive use. No part of this page shall be reproduced in any form or by any electronic or mechanical means (including photocopying, recording, CD reproduction or any information storage and retrieval system) without written permission from the Biology Department of Xavier University.  Biology Department College of Arts & Sciences BIOL 113 L – Animal Histology Prepared by L. Saab and P. Fudalan Activity 2. Cells of Hematopoietic Islands Identification of the cells in hematopoietic islands is quite complicated due to the large number and kinds of cells at different stages of development. These cells are randomly mixed during the preparation of the tissue. To identify each cell, one must consider both the cytoplasmic and nuclear features, and its color. A. Examine closely the cells in a bone marrow smear using the oil immersion objective. B. Look for each cell described below. (Warning: Cells may not be all intact and cannot be all found in a single bone marrow smear. You may use another slide of bone marrow smear) C. Choose one intact cell of each developing stage. D. Photograph one cell and paste it on the labeled boxes in Worksheet 6. (No need to label the parts of each cell. The cells of the hematopoietic compartment are the following: I. Hemocytoblast or Stem Cell (Plate 2) Nucleus is round to oval with fine chromatin arranged in a sieve-like reticulum. Nucleoli are prominent. Cytoplasm is with basophilic to azurophilic (aniline blue) granules. It differentiates into progenitor cell which in turn become precursor cell of both red and white blood cell series. Plate 2. Hemocytoblast II. ERYTHROCYTE SERIES The developing stages of red blood cells are numbered here according to the order of the stages of development: 1. Proerythroblast (Plate 3) Nucleus is large, ovoid and centrally located with a regular checker board-like distribution of chromatin material. Two nucleoli are generally present. Cytoplasm is intensely basophilic (dark blue) due to ribosomes, and with white rim around the nucleus. Plate 3 Proerythroblast 2 This material is owned by Biology Department – Xavier University and it is for exclusive use. No part of this page shall be reproduced in any form or by any electronic or mechanical means (including photocopying, recording, CD reproduction or any information storage and retrieval system) without written permission from the Biology Department of Xavier University.  Biology Department College of Arts & Sciences BIOL 113 L – Animal Histology Prepared by L. Saab and P. Fudalan 2. Basophilic erythroblast (Plate 4) Smaller than proerythroblast. Nucleus is rounded and centrally located, but chromatin material is coarser and clumped. Cytoplasm is deeper blue (basophilic) due to more free ribosomes and initiation of hemoglobin synthesis. Plate 4. Basophilic erythroblast 3. Polychromatophilic erythroblast(Plate 5) Nucleus is smaller than in basophilic erythroblast. Chromatin is even more condensed and has a “cart-wheel” appearance. Nucleoli are absent. Cytoplasm has varying shades of grayish-blue, lilac, reddish or pink. Plate 5. Polychromatophilic erythroblast 4. Orthochromatic erythroblast or Normoblasts (Plate 6) Small, nucleus is compact an intensely heterochromatic (dark blue) due to highly condensed. chromatin. The cytoplasm is lilac but may contain traces of basophilia to ribosomes and slightly acidophilic due to increased hemoglobin. The last stage that divides. Plate 6. Orthochromatic erythroblast or Normoblasts 5. Polychromatophilic erythrocyte or Reticulocyte (Plate 7) The once normoblast without nucleus , or with a nucleus ready to be expelled. Cytoplasm is reticulated and reddish pink due hemoglobin and with slightly diffused basophilia due to residual ribosomes. It is an immature red blood cell ready to exit from the bone marrow. Plate. 7. Polychromatophilic erythrocyte or Reticulocyte 3 This material is owned by Biology Department – Xavier University and it is for exclusive use. No part of this page shall be reproduced in any form or by any electronic or mechanical means (including photocopying, recording, CD reproduction or any information storage and retrieval system) without written permission from the Biology Department of Xavier University.  Biology Department College of Arts & Sciences BIOL 113 L – Animal Histology Prepared by L. Saab and P. Fudalan C. GRANULOCYTES SERIES Cells are characterized by lobed nucleus and specific cytoplasmic granules. The following developing stages of granulocytes are numbered according to sequence. 1. Myeloblast or Leucoblast (Plate 8) Stem cell that differentiates into the granulocyte series. Large cell with ovoid nucleus containing delicate chromatin in threadlike arrangement. Two to five nucleoli are present. Cytoplasm slightly basophilic due to scattering of ribosomes, and with a few azurophilic granules. Plate 8. Myeloblast or Leucoblast 2. Promyelocyte (Plate 9) Nucleus is somewhat elongated and contains nucleoli and clumped chromatin. Cytoplasm is greater than that myeloblast and with more azurophilic (primary) granules. Plate 9. Promyelocyte 3. Myelocyte (Plate 10) Nucleus is ovoid and usually eccentric and with coarse chromatin and no nucleoli. Cytoplasm may have azurophilic granules but there are more specific (secondary) granules. The cell can be distinguished by the color of the cytoplasm as neutrophilic myelocyte (pale blue) eosinophilic (pinkish) myelocyte and basophilic myelocyte (lilac). Plate 10. Myelocyte 4 This material is owned by Biology Department – Xavier University and it is for exclusive use. No part of this page shall be reproduced in any form or by any electronic or mechanical means (including photocopying, recording, CD reproduction or any information storage and retrieval system) without written permission from the Biology Department of Xavier University.  Biology Department College of Arts & Sciences BIOL 113 L – Animal Histology Prepared by L. Saab and P. Fudalan 4. Metamyelocyte Nucleus has deep indentation or bean-shaped. Cytoplasm is pink or lilac with numerous specific granules. The cell is further classified as: Basophilic metamyelocyte (Plate 11) Nucleus indented, cytoplasm pale blue with dark purple granules. Rare or scarce in most bone marrow smear. Plate 11. Basophilic metamyelocyte Eosinophilic metamyelocyte. (Plate 12) Nucleus deeply indented (about half of the nucleus). Cytoplasm has orange specific granules Plate 12. Eosinophilic metamyelocyte Neutrophilic metamyelocyte (Plate 13) Nucleus is slightly indented (less than half of the nucleus). Cytoplasm contains abundant specific and azurophilic granules. Plate 13. Neutrophilic metamyelocyte 5. Band form or Stab form Nucleus indentation is more than one third of the nucleus, or appears C, U or S shaped. Can be distinguished as: Basophil band form (Plate 14) Cytoplasm is pale blue with dark purple and black granules Plate 14. Basophilic band form 5 This material is owned by Biology Department – Xavier University and it is for exclusive use. No part of this page shall be reproduced in any form or by any electronic or mechanical means (including photocopying, recording, CD reproduction or any information storage and retrieval system) without written permission from the Biology Department of Xavier University.  Biology Department College of Arts & Sciences BIOL 113 L – Animal Histology Prepared by L. Saab and P. Fudalan Eosinophil band form (Plate 15) Cytoplasm is colorless or cream-colored with pale to dark pink specific granules Plate 15. Eosinophilic band form Neutrophil band form (Plate 16) Cytoplasm is pinkish with bluish or purple azurophilic granules Plate 16. Neutrophil band form 6. Segmented form or Mature granulocyte Nucleus is centrally or eccentrically located and separated into lobes or segments. Chromatin is dark purple, coarse, and clumpy. Basophil (Plate17) Nucleus is usually of two lobes and obscured by numerous granules. Cytoplasm with basophilic or dark purple granules Plate 17. Basophil Eosinophil (Plate 18) Nucleus is of 2 -3 lobes and cytoplasm. Cytoplasm is cream-colored to colorless with pale to dark pink specific granules Plate 18. Eosinophil Neutrophil (Plate 19) Nucleus is of 2 -5 lobes with reddish purple azurophilic granules Plate 19. Neutrophil 6 This material is owned by Biology Department – Xavier University and it is for exclusive use. No part of this page shall be reproduced in any form or by any electronic or mechanical means (including photocopying, recording, CD reproduction or any information storage and retrieval system) without written permission from the Biology Department of Xavier University.  Biology Department College of Arts & Sciences BIOL 113 L – Animal Histology Prepared by L. Saab and P. Fudalan C. PLATELET SERIES 1. Megakaryoblast (Plate 20) Nucleus is large, oval, or kidney-shaped or lobed with several nucleoli. Has very high nucleus to cytoplasm ratio. Cytoplasm is deeply basophilic and agranular. Plate 20. Megakaryoblast 2. Promegakaryocyte (Plate 21) Nucleus have overlapping nuclear lobes with coarse chromatin but evenly distributed and has lower nucleus to cytoplasm ratio. Cytoplasm is less basophilic or pinkish and contain azurophilic granules. It is larger than megakaryoblast. Plate 21. Promegakaryocyte 3. Megakaryocyte (Plate 22) Nucleus has multiple lobes tightly packed together but extend through much of the cell, and has coarsely granular clumped chromatin. Cytoplasm is pale- staining and contains numerous azurophilic granules. The fragmentation of its cytoplasm produce platelets. Plate 22. Megakaryocyte 7 This material is owned by Biology Department – Xavier University and it is for exclusive use. No part of this page shall be reproduced in any form or by any electronic or mechanical means (including photocopying, recording, CD reproduction or any information storage and retrieval system) without written permission from the Biology Department of Xavier University.  Biology Department College of Arts & Sciences BIOL 113 L – Animal Histology Prepared by L. Saab and P. Fudalan Activity 3. Answer the following questions: 1. Give the committed (mature) cell or product on each series of blood cell formation by filling- in Table 1. Table 1. The committed cell of blood cell series Series of Cell Maturation Cells or Product A. Erythrocyte Series B. Granulocyte Series C. Platelet Series 2. What caused the cytoplasmic staining affinities of the basophilic erythroblast, polychromatophilic erythroblast, normoblast and erythrocyte? Fill in Table 2. Table 2. Functional significance of the cytoplasmic staining affinities. Cell Cause of Staining Affinity A. Basophilic erythroblast B. Polychromatophilic erythroblast C. Orthochromatic erythroblast/Normoblast D. Erythrocyte Reflection/Realization: 3.Why are patients with blood cancer may be treated with bone marrow transplant? End 8 This material is owned by Biology Department – Xavier University and it is for exclusive use. No part of this page shall be reproduced in any form or by any electronic or mechanical means (including photocopying, recording, CD reproduction or any information storage and retrieval system) without written permission from the Biology Department of Xavier University.