1. BLOOD TISSUE

2. BLOOD Blood is considered a connective tissue because it has a matrix It is made up of two parts Formed elements, or blood cells Plasma the liquid in which the formed elements are suspended The formed elements are Erythrocytes (red blood cells) Platelets (Thermbocytes) andleukocytes (white blood cells) The fluid portion of whole blood, its matrix, is commonly called plasma

3. Copyright 2009, John Wiley & Sons, Inc. Formed Elements of Blood

4. White blood cells Platelets Red blood cells Artery

5. Human blood smear, with RBCs, WBCs and platelets Neutrophil Lymphocyte RBC Platelets Dr. A. Kent Christensen

6. 1) Plasma 2) The Formed Elements (blood cells/cell fragments) Composition of the Blood

7. If blood is removed from the circulatory system, it will clot This clot contains formed elements and a clear yellow liquid called SERUM which separates from the coagulum Blood that is collected and kept from coagulating by the addition of anticoagulants (eg, heparin, citrate) Separates when centrifuged into layers that reflect its heterogeneity The normal value is 40–50% in men and 35–45% in women

9. Plasma- 55% Formed elements- 45% Buffy coat- <1%

13. Plasma Liquid plasma-imparts fluid properties to blood Plasma components -water(90%) -proteins (albumin, globulins and fibrinogen) electrolytes -waste material -nutrients (glucose, lipids and amino acids) -blood gases (oxygen, carbon dioxide and nitrogen) -regulatory substances (hormones and enzymes)

14. Erythrocytes

15. ERYTHROCYTES A nucleate cells, devoid of organelles 7-8 mm, biconcave disk, maximized cell surface area Contain hemoglobin (transport of oxygen and carbon dioxide) Develop from pro erythroblast Developed in bone morrow

17. Red blood cells in a blood smear RBC Platelet Mizoguti slide collection (J). J-199.

18. RBC, transmission electron microscopy Erlandsen's slide set (MH). MH-2G3.. Platelet RBC

19. Platelets — Thrombocytes or PLTs — Formed in the bone marrow — Fragments from the cytoplasm of megakaryocytes — Smallest of the blood cells — 1-4 micrometers in diameter — Shape can be round, oval, or appear spiky — Life span of around 8-12 days

20. Platelets — Involved in the clotting process — Seal wounds and prevent blood loss — Help repair damaged vessels — 150,000 – 400,000 per microliter of blood — Platelets stain bluish with reddish or purple granules

21. Platelets (at right) in a blood smear Mizobuti histology slide set (J). J-186. Platelet

22. Transmission electron micrographs of a platelet seen in cross section (above) and in a section in the plane of the disk (below) Fawcett's Histology, 11th edition, page 118. granule membrane tubule

23. White Blood Cells Leukocytes or WBCs — Largest sized blood cells — Lowest numbers in the blood (4,500 – 11,000 per microliter) — Formed in the bone marrow and some in lymph glands — Primary cells of the immune system — Fights disease and foreign invaders — Contain nuclei with DNA, the shape depends on type of cell — Certain WBCs produce antibodies — Life span is from 24 hours to several years — Size is 8-20 micrometers in diameter — There are five different types of WBCs 1. Neutrophils 2. Eosinophils 3. Basophils 4. Lymphocytes 5. Monocytes

24. LEUKOCYTES Possession of specific and non specific (azurophilic granules) Granulocytes Agranulocytes Neutrophils Lymphocytes Eosinophils Monocytes Basophils

25. NEUTROPHILS Most numerous 10-12mm Multilobed nucleus (polymorphonuclear neutrophils) Heterochromatin and euchromatin Tertiary granules Motile cells Active phagocytes at the site of inflammation

26. Two neutrophils in a blood smear Mizoguti slide set (J). J-196. LM appearance in smear: About 9-12 µm in diameter (thus larger than RBC). Nucleus long and multi-lobed (usually 2-4 lobes). Cytoplasm has small, neutrally stained specific granules. Non-specific granules are azurophilic.

27. Neutrophil, transmission electron micrograph Specific granule Lysosome (=azurophilic granule) TEM appearance: Multi-lobed nucleus and numerous specific granules and lysosomes (=azurophilic granules in LM). Erlandsen's slide set (MH). MH-2F6.

29. EOSINOPHILS Similar size Bilobed nucleus (heterochromatin and euchromatin) Large, eosinophilic, refractile granules Azurophilic granules-lysosomes Function Allergic reactions Parasitic infections Chronic inflammation

30. Eosinophil in a human blood smear University of Michigan Virtual Slide Collection LM appearance in smear: About 10-14 µm in diameter. Bilobed nucleus. The cytoplasm has prominent pink/red specific granules (stained with eosin dye). If the smear is not stained properly, the granules may be brownish.

31. BASOPHILS Least numerous Lobed nucleus obscured by the basophilic granules Heterochromatin/euchromatin Speci fi c granules (heparin, histamine, heparan, sulfate and leukotrienes) Azurophilic granules (lysosomes) FUNCTION Closely related to the mast cells-­ ‐ hypersensitivity and anaphylaxis (bind Ab secretd by plasma cells)

32. Comparison of basophil and eosinophil in a blood smear Basophil Eosinophil J.M. Velkey.

33. Eosinophil, transmission electron microscopy internum externum TEM appearance: The specific granules are ovoid in shape, and contain a dark crystalloid body composed of major basic protein (MBP), effective against parasites. The rest of the granule contains other anti-parasitic substances and histaminase. The cytoplasm also contains lysosomes (=azurophilic granules). Fawcett's Concise Histology, 2nd edition, page 49.

34. LYMPHOCYTES The main functional cells of the immune system 30% total blood leukocytes Recirculating immuno competent cells Small, medium, large (6-30mm) Slightly indented, spherical nucleus Thin cytoplasm (small lymphocytes) T lymphocytes – cell-mediated immunity B lymphocytes – production of circulating Ab Natural killer cells (NK cells) – programmed to kill virus-infected cells and some tumor cells

35. Small lymphocyte in a blood smear LM appearance in smear: Small lymphocyte (about 90% of lymphocytes you will see) are ~8 µm in diameter, while large lymphocytes may be up to about 15 µm. Round, dense nucleus (abundant heterochromatin). The cytoplasm of a small lymphocyte is a narrow rim around the nucleus, and when well-stained is pale blue. Small lymphocyte Mizobuti histology slide set (J). J-186.

36. Large lymphocyte in a blood smear LM appearance in smear: Small lymphocytes (about 90% of lymphocytes you will see) are ~8 µm in diameter, while large lymphocytes may be up to about 15 µm with ovoid, dense nuclei (abundant heterochromatin). Large lymphocyte Mizoguti slide set (J). J-187.

37. Electron micrograph of a lymphocyte TEM appearance: The cytoplasm doesn't appear to be very active, containing mainly mitochondria and free ribosomes. Mitochondrion Centriole Erlandsen slide set (MH). MH-2E7

38. Tissue plasma cells (derived from B-lymphocytes) Erlandsen slide set (MH). MH-2F1 Erlandsen slide set (MH).

39. MONOCYTES Precursors of the cells of the mononuclear phagocytotic system Largest leukocytes - 18 mm Travel from the bone marrow to the body tissues where they differentiate Indented nucleus FUNCTION Antigen-presenting cells in the immune system and phagocytosis

40. Monocyte in a blood smear LM appearance in smears: About 16 µm in smears, thus the largest leukocyte. Large, eccentric nucleus either oval, kidney- shaped or horseshoe-shaped, with delicate chromatin that is less dense than that of lymphocytes. Pale cytoplasm, often grayish, may contain occasional stained granules (lysosomes = azurophilic granules). Large lymphocytes may resemble monocytes, but the lymphocyte nucleus is usually more dense. Mizoguti slide collection (J). J-188.

41. Monocyte, transmission electron microscopy TEM appearance: Cytoplasm contains mitochondria and some small lysosomes. Lysosome (=azurophilic granule) Mitochondrion Centriole Golgi Erlandsen's slide set (MH). MH-2F3.

42. THROMBOCYTES Small, membrane bounded anucleate cytoplasmatic fragments, derived from megakarioblasts (bone marrow) 2-3mm FUNCTION Surveillance of blood vessels Blood clot formation Repair of injured tissue

43. granulocyte This granulocyte has very tiny light staining granules (the granules are very difficult to see). The nucleus is frequently multi-lobed with lobes connected by thin strands of nuclear material. These cells are capable of phagocytising foreign cells, toxins, and viruses. When taking a Differential WBC Count of normal blood, this type of cell would be the most numerous Normally, neutrophils account for 50-70% of all leukocytes If the count exceeds this amount, the cause is usually due to an acute infection such as Neutrophil appendicitis, smallpox or rheumatic fever If the count is considerably less, it may be due to a viral infection such as influenza, hepatitis, or rubella