Lecture 2 Histology of Blood Cells 1 PDF

Faculty of Medicine Academic Year: 2024-2025 Year: 1 Semester: 1 Module: BLOOD and body fluids (blf) 103 Histology of Blood cells I By: Safinaz Salah Eldin Professor of histology, faculty of medicine , Cairo university Department: Histology 12/30/2024...

Faculty of Medicine Academic Year: 2024-2025 Year: 1 Semester: 1 Module: BLOOD and body fluids (blf) 103 Histology of Blood cells I By: Safinaz Salah Eldin Professor of histology, faculty of medicine , Cairo university Department: Histology 12/30/2024 22  Objectives 1. Recognize different blood elements. 2. Describe the histological characteristics of RBCs, leucocytes (granular, non-granular) & platelets at L.M. and E.M. levels 3. Correlate normal RBCs structural adaptation for proper function. 4. Relate RBCs structural abnormalities to some clinical conditions (e.g. hemolytic anemia) 5. Differentiate between RBCs and WBCs. 6. Recall normal RBCs, leucocytic and platelet count. 7. Correlate the ultrastructure components of platelets to their function. 8. Discriminate different types of WBCs from each other in various blood films. 12/30/2024 BLF - 103 33  Objectives 9. Point out abnormal variations in count and shape of RBCs. 10.Identify deviation in WBCs and platelet counts and some of their causes. 11.Interpret alterations in RBCs, WBCs and platelet count and relate them to the possible clinical conditions. 12.Define the total & differential leucocytic count. 13.Describe the histological organization & sites of the bone marrow. 14.Identify types of bone marrow. 15.Recognize the histological structure of the cells involved in various stages of hemopoiesis. 12/30/2024 BLF - 103 44  Introduction Red blood Blood elements corpuscles Blood 45% Special type of Leucocytes connective tissue Platelets Plasma 55% 12/30/2024 BLF - 103 55  Introduction Blood examination Blood film Leishman’s stain (neutral stain ) Basic stain Dissolved in Acidic stain Methylene methyl alcohol Eosin (fixative ) blue 12/30/2024 BLF - 103 6 12/30/2024 BLF - 103 7  Red blood corpuscles (RBC’s) Erythrocytes L.M Shape Titles Size E.M Life span Number Histologic features of osmotic fragility Adaptation to function 12/30/2024 BLF - 103 8  RBCs L.M In unstained blood film: RBCs appear colored due to Hb. In Leishman’s stained blood film : Rounded, non-nucleated Acidophilic (Hb is a basic protein) pale center (1/3 the diameter) = Normochromic. 12/30/2024 BLF - 103 9 12/30/2024 BLF - 103 10  Shape Non nucleated Side view : biconcave discs +++++ surface area Top view: rounded 12/30/2024 BLF - 103 11 Abnormal shapes: Due to changes in cell membrane or hemoglobin content spherocytes (spherical), ovalocytes (oval in shape), sickle cell (crescent-shaped), poikilocytes (pear- shaped) more fragile, more prone to hemolysis ----- anemia. 12/30/2024 BLF - 103 12  Normal shape Spherocytes Sickle cell Ovalocytes 12/30/2024 BLF - 103 13  Size Normal size: Diameter: 6-9 um with an average 7.5 um. Thickness : edge 2.2 um , center 0.8 um. Abnormal sizes: Microcytes RBCs (< than 6 um) Macrocytes (> than 9 um) Anisocytosis (different sizes). 12/30/2024 BLF - 103 14  E.M No nucleus No organelles contain hemoglobin Hb appears electron-dense & homogenous. The cell membrane is flexible. Cytoskeleton actin & spectrin maintain membrane shape,& stability. Glycocalyx includes antigenic sites for blood groups & Rh factor. 12/30/2024 BLF - 103 15  Life span & fate 120 days. Old RBCs are phagocytosed by macrophages: in liver, bone marrow and spleen. It is excreted as bile pigments Iron is reused to form new RBCs 12/30/2024 BLF - 103 16 Histologic features of osmotic fragility Plasma (Isotonic solution 0.9 % saline) Normal shape Hypertonic solution Crenation: shrink and show notches. Hypotonic solution Hemolysis swell, burst and leak hemoglobin. The remaining cell membrane cell ghost. 12/30/2024 BLF - 103 17  Number By the hemocytometer or electronic counting instruments. Average number: 5 millions /mm 3. Normal adult male: 5 - 5.5 million/mm 3. Adult females: 4.5 -5million/mm 3stimulatory effects of male hormones on the bone marrow. 12/30/2024 BLF - 103 18 Abnormalities in Number Anemia: < 4 million/mm 3 (oligocythemia) and/or decreased hemoglobin concentration. Polycythemia: > 6 million/mm3,due to: Hypoxia that stimulates the bone marrow. It may be: Physiological e.g. high altitudes Pathological e.g. chronic lung and heart diseases. 12/30/2024 BLF - 103 19  Adaptation to function Factor Mode of adaptation Plasmalemma Flexible _____ squeeze inside narrow cappilaries Lipoprotein ____highly selective for gas exchange Shape Biconcave ++++ surface area for gas exchange Rounded edges __esay passage in branched vessels Content No nucleus no organells +++ space Hb Enzymes: Hb reductase Carbonic anhydrase 12/30/2024 BLF - 103 20  White blood cells (Leucocytes ) Types Titles General characters leucocytic count Granular leucocytes Non granular leucocytes 12/30/2024 BLF - 103 21 General characters Types: Five types Content: True cells with nuclei and organelles Number: total count 4000-11000/mm3 Life span: days to years Shape & size : spherical , 6-20 um Motile with defensive functions 12/30/2024 BLF - 103 22  Leucocytes Granular Non granular Leucocytes leucocytes Granular Leucocytes Neutrophils Lymphocytes according to the affinity of their eosinophils Monocytes specific granules to stain Basophils classify into 12/30/2024 BLF - 103 23  leucocytic count Total leucocytic count = 4.000 to 11.000/mm3. Abnormalities in total count Leukocytosls: > 11,000/mm3 Physiological & Pathological due to either acute or chronic infections. Leukopenla: < 4,000/mm 3 due to X-ray, irradiation typhoid fever, influenza virus or excessive use of some antibiotics. 12/30/2024 BLF - 103 24 Cont leucocytic count Counted by: Haemocytometer & Electronic counting instrument. leukemia: Bone marrow cancer __very high count. Peripheral blood shows immature WBCs. Differential leukocytic count: Percentage of each type of WBCs to the total number. Counted in a blood film stained with Leishman_stain. 12/30/2024 BLF - 103 25  Granular leucocytes ❖ Short life span (few days) ❖ Single, condensed nucleus but segmented. ❖ Nucleus with peripheral heterochromatin & central euchromatin ❖ Few organelles (Golgi apparatus, mitochondria, rER). ❖ Contain non-specific (azurophilic) lysosomes & specific granules. ❖ Azurophilic have affinity for azure dye 12/30/2024 BLF - 103 26 Specific granules Bind neutral, basic, or acidic stains Have specific functions 12/30/2024 BLF - 103 27 Neutrophils (Polymorphonuclear leucocytes) P.M.Ns. 60-70% , 10-12 µm diameter. Life span few days L.M.: Cytoplasm: - specific granules; numerous fine, pale granules. Azurophil granules: few, large, stain purple with azure dye. 12/30/2024 BLF - 103 28 Neutrophil Nucleus: Single segmented nucleus 2-5 lobes connected by thin chromatin thread Dark & has many shapes [P.M.N.]. Barr body: In females, inactive X chromosome may appear as a drumstick-like appendage can be seen in 3-6% of female cells. 12/30/2024 BLF - 103 29 Neutrophils E.M Nucleus: Peripheral heterochromatin & small central euchromatin. Cytoplasm: Have pseudopodia. Few organelles, More glycogen [Energy) Two types of Granules: primary & secondary 12/30/2024 BLF - 103 30 Neutrophil’s granules 1. Azurophilic primary granules Large, few, dark, considered as 1ry lysosomes. Contain Myeloperoxidase defenses against bacteria & viruses 2. Specific [secondary]: Small, many and pale. Contain Collagenase, Phagocytin, Lysozyme and Lactoferrin. 12/30/2024 BLF - 103 31 Neutrophil Functions: 1st line of defense (non-specific) Bacterial toxins attract neutrophils. Leave blood to C.T Diapedesis: migrate between endothelial cells of B.V. Become motile & have pseudopodia [microphages]. 12/30/2024 BLF - 103 32 Continue functions in connective tissue they 1) Phagocytose bacteria: Lactoferrin binds to iron [Bacteriostatic] Phagocytin : kill bacteria [bactericidal]. Lysozyme destroys bacterial proteins. Collagenase: destroys collagen facilitates their movement. Myeloperoxidase kill bacteria & other enzymes cause their lysis. 12/30/2024 BLF - 103 33 Cont neutrophil functions 2.Dead neutrophils form pus cells. 3.Pus increase body temperature to stimulate the heat regulating center in brain. 4. Attract monocytes to site of infection to clean it 5. Stimulate bone marrow to form more neutrophils. 6. Secrete trephone substance: help healing of wounds. 12/30/2024 BLF - 103 34 Cont neutrophils Neutrophilia: Increased percentage of neutrophils >75%, due to acute pyogenic infection e.g. Acute tonsillitis, acute appendicitis & abscess. Neutropenia: Decreased percentage of neutrophils < 60% due to: Typhoid fever (the commonest cause), Tuberculosis (T.B.) ,Viral infection as influenza. 12/30/2024 BLF - 103 35 Cont neutrophils Clinical note Band cell Immature neutrophils Large numbers of immature neutrophils (band cells) in the blood, sometimes called a “shift to the left,” is clinically significant, usually indicating a bacterial infection. 12/30/2024 BLF - 103 36  Eosinophils 1-4 % , 10-14 µm diameter. Life span few days L.M. Nucleus: bilobed horse shoe shaped connected by thick chromatin threads. Cytoplasm: large acidophilic specific granules 12/30/2024 BLF - 103 37 Cont eosinophils E.M. Nucleus: peripheral heterochromatin with central euchromatin. Cytoplasm: Few organelles & two types of granules: Azurophil: Small = lysosomes Specific: oval with electron-·· dense core of basic protein [internum] & less dense periphery [externum]. 12/30/2024 BLF - 103 38 Cont eosinophils functions Terminate the allergy by: Sulphatase to destroy histamine & heparin. Phagocytose antigen-Ab. Defend against parasites: Cytotoxic effect of internum form pores in their bodies. Neurotoxins _ nervous dysfunction of parasites. 12/30/2024 BLF - 103 39 Cont eosinophils abnormal count Eosinophilia: increase percentage> 5%. It occurs in: 1.Allergic diseases: Urticaria, eczema & bronchial asthma 2.Parasites as Bilharziasis Eosinopenia: decrease percentage < 1% cortisone treatment ---+ inhibit their release from bone marrow. 12/30/2024 BLF - 103 40  Basophils 0-1%, 10-12 µm diameter Life span few days L.M.Nucleus: irregular segmented S shaped Cytoplasm: Contain coarse basophilic granules obscure the nucleus. Metachromatically stained by toulidine blue purple 12/30/2024 BLF - 103 41 Cont E.M. basophils Nucleus: peripheral heterochromatin with central euchromatin. Cell membrane shows receptors for lgE Cytoplasm: Few organelles & two types of granules: Azurophil: Small =lysosomes Specific: Large, rounded, electron dense & contain: Histamine, Heparin,Eosinophil chemotactic factor, Leukotriens. 12/30/2024 BLF - 103 42 Cont functions basophils 1. Secrets heparin prevents clotting & promotes allergy. 2. Secrete Histamine –V.D. sudden decrease in BP anaphylaxis. 1. Attract eosinophils to site of allergy by ECF 2. Leukotrienes - bronchospasm -bronchial asthma. 3. Limited phagocytic power 12/30/2024 BLF - 103 43 Cont basophils Basophilia Increase in basophil percentage >2% Occurs in: Allergic diseases Viral infection (chicken pox )liver cirrhosis 12/30/2024 BLF - 103 44  Basophils Mast cells Life span Few days Longer weeks to months Size 10-12 µm 20-30 µm Nucleus Segmented Rounded Phagocytosis Slight No Granules Metachromatically stained due to histamine and heparin Surface receptor Antibody IgE 12/30/2024 BLF - 103 45  Interactive Question A differential cell count of a blood smear from a patient with a parasitic infection is likely to reveal an increase in the circulating numbers of which cell type? a. Neutrophils b. Lymphocytes c. Monocytes d. Basophils e. Eosinophils 12/30/2024 BLF- 103 46 46  Interactive Question A 43-year-old woman is working in her gardenwithout gloves. Athorn deeply penetrates her forefinger. The next day the area has become infected with pus at the wound site. Which of the following cells function in the formation of pus? a. Cells with spherical nuclei and scant cytoplasm b. Biconcave cells with no nuclei c. Cells with bilobed nuclei and many acidophilic cytoplasmic granules d. Very small, cell-like elements with no nuclei but many granules e. Cells with polymorphic, multiply lobed nuclei 12/30/2024 BLF - 103 47 47  Summary l.M. Types WBCs RBCs Count Leucocytic count Size, shape Total & differential Color Granular lecocytes Adaptation Netrophils,eosinphilis, basophils 12/30/2024 BLF - 103 48 48  References Junqueira’s Basic Histology: Text and Atlas, (2018)15th Edition by Anthony Mescher chapter 12 pp 248 12/30/2024 BLF - 103 49 49