Blood Leucocytes PDF

Blood Leucocytes Updated January, 2023 Dr. Mohamed Hindawy Blood leucocytes...

Blood Leucocytes Updated January, 2023 Dr. Mohamed Hindawy Blood leucocytes 1. Granular leucocytes Neutrophil Eosinophils Basophils Percentage 60 70% 1 5% 0.5 1 % Diameter 10 12 µm 12 15 µm 10 12 µm * Multilobed (2 5 lobes) Bilobed S- Shaped or irregular, masked Nucleus * Barr body: condensed x-chromatin seen as a by granules. drumstick appendage in 60% of neutrophils of normal females. 1. 1ry (azurophilic = nonspecific) 1. 1ry (azurophilic = nonspecific) 1. 1ry (azurophilic = nonspecific) granules: 20 % & large. They are granules: very few, small & granules: very few & small. Cytoplasmic granules contain contain eosinophil peroxidase. 2. 2ry (basophilic = specific) Structure lysosomes, myeloperoxidase & defensins. 2. 2ry (acidophilic = specific) granules: are much & large. They 2. 2ry (neutrophilic = specific) granules: are much, large & mask the nucleus and can be contain: stained metachromatically with granules: 80 % & small, contain LM i) Major basic protein toluidine blue (take magenta collagenase & lactoferrin. antiparasitic + degranulate color) & contain: 3. 3ry granules: contain gelatinase mast cells & basophils. Histamine, SRS-A, ECF & Heparin. & adhesion molecules. ii) Histaminase & 4. Secretory granules: contain arylsulphatase. membrane receptors & alkaline phosphatase.  EM Azurophilic granules are Specific granules contain crystalloid Specific granules are dense & denser than neutrophilic dense cores (Internum) surrounded irregular granules. by pale matrix (Externum). Functions 1. Microphage. 1. Antiparasitic: The secrete the following mediators: 2. It secretes: extracellular killing 1. Histamine: induces ALLERGY i) Monocyte Chemotaxin of parasitic larvae. (rapid onset & short duration). attract monocytes 2. Phagocytosis: and 2. SRS-A (Slow Reacting Substance (macrophages) to the site of intracellular of Anaphylaxis) formed of infection. digestion. leukotrienes & prostaglandins ii) Bone marrow stimulating 3. Induce allergy: by which induces ANAPHYLAXIS factor produce more degranulation of mast (slow onset & long duration). neutrophils. cells & basophils. 3. ECF (Eosinophil Chemotactic iii) Proteolytic enzymes 4. Anti-allergic: Factor): which attract eosinophils formation. release histaminase to destroy mediators of allergy. iv) Trephone substance destroys histamine & 4. Heparin (natural anticoagulant). stimulate tissue repair. arylsulphatase v) Pyrogens: induce fever. destroys SRS-A. Blood Leucocytes Updated January, 2023 Dr. Mohamed Hindawy 2. Non-granular (Agranular) leucocytes Lymphocytes Monocytes Small lymphocytes Medium lymphocytes * All lymphocytes constitute 20 40 % of total leucocytes 3 8% Percentage * 90 % are small & 10 % are medium-sized * 70 % are T cells & 30 % are B cells Size 4 7 µm 10 12 µm 12 15 µm Central, large, round, condensed Central, large, indented, paler Central, large, kidney-shaped, Nucleus than small lymphocyte pale * Pale basophilic * More basophilic * Pale basophilic Structure * Thin rim around the nucleus * Much cytoplasm than small * Abundant Cytoplasm Lymphocytes. LM  Free ribosomes & a small Some rER & Golgi + some * Few rER + Good Golgi + much lysosomes EM Golgi + few mitochondria mitochondria (azurophilic granules) + much mitochondria. * Surface pseudopodia [I] B lymphocytes Essentially Macrophages but also Antigen 1. Humoral immunity: when stimulated by T-Helper Cs (TH), they develop Presenting Cells: they stay in blood for about into plasma cells secret specific antibodies that attack 72 hours then migrate to different body EXTRACELLULAR PATHOGENS. tissues to form members of the macrophage 2. Memory B lymphocytes: they mediate 2ry immune response. system that includes: [II] T lymphocytes (1) CT proper Histiocytes (clasmatocytes) ** Immune- regulatory cells (2) Synovium of joints Type-A synoviocytes. 1. T-Helper Cs (TH) Activate T & B cells. (3) Bone Osteoclasts. Functions 2. T-Regulatory Cs (Treg) prevent over activity of immune response. (4) Bone marrow macrophages. (5) CNS Microglia. ** T- effector cells (6) Lung alveolar macrophages. 1. T-Cytotoxic Cs (TC) virally infected, transformed cells & (8) Lymph node: Histiocytes. allogenic cells. (9) Spleen Littoral cells. 2. T- (10) Liver Von Kupffer cells. hypersensitivity. (11) Kidney Mesangial cells. ** T- memory cells mediate 2ry immune response. (12) Placenta Hofbauer cells. [III] Null (Non-B Non-T) Lymphocytes = Natural killer (NK) (13) Peritoneum Peritoneal macrophages. lymphocytes Non-specific killer of virally infected, transformed cells & allogenic cells.