Blood PDF

BLOOD Chapter 4 BLOOD Blood Is a special type of connective tissue. (Mesenchymal in origin). Stain: Neutral stain → as Leishman’s Stain (Eosin + Methyline blue dessolved in methyl alcohol) B...

BLOOD Chapter 4 BLOOD Blood Is a special type of connective tissue. (Mesenchymal in origin). Stain: Neutral stain → as Leishman’s Stain (Eosin + Methyline blue dessolved in methyl alcohol) BLOOD CELLS 45% PLASMA 55% Red blood corpuscles [erythrocytes] Water 90% White blood cells [Leucocytes] 9% organic compounds e.g. Platelets [Thrombocytes] Proteins & Hormones... 1% inorganic salts: Ca, Mg … ERYTHROCYTES OR RED BLOOD CORPUSCLES (RBCS):  Origin: Red bone marrow.  Shape:  Non-nucleated.  Biconcave disc-shaped cells in side view.  Rounded in top view.  Thick periphery 2.2 µm - thin center of 0.8 µm.  In slow circulation: RBC's adhere to each other like pile of coins (rouleaux appearance) due to high surface tension. Which is non-permanent. 9 These long chains of RBCs sediment more easily. 9 This is the mechanism for increased "Erythrocyte Sedimentation Rate"(ESR), which increases non-specifically with inflammation. Abnormal Shapes: due to changes in the cell membrane or Hb.  Spherocytes (spherical)  Ovalocytes (oval in shape)  Sickle cell (crescent-shaped)  Poikilocytes (pear-shaped) RBCs. They are more fragile & more prone to hemolysis causing anemia. HISTOLOGY with ZAHRA Stain 53 4 Chapter BLOOD  Size: The normal diameter of an RBC ranges from 6 -9 µm with a mean of 7.5 µm. Abnormal sizes:  Microcysts RBCs (less than 6 pm)  macrocytic (more than 9 pm)  Anisocytosis (different sizes).  Color: (LM)  Unstained blood film. RBCs appear colored due to Hb.  with Leishman’s stain, the erythrocytes appear acidophilic (Hb is a basic protein), with pale center (about ⅓ of the diameter) (Normochromic RBCs)  Structure and composition: (EM)  Mature RBC lack nucleus and organelles. giving more space for hemoglobin.  RBC cytoplasm contains about: 9 66% water 9 33% hemoglobin (Hb) which appears electron-dense & homogenous. 9 1% Enzymes as: carbonic anhydrase and Hb reductase.  RBCs are surrounded by flexible lipoprotein cell membrane. 9 Inner surface cell membrane is associated with cytoskeleton protein (actin & myosin) to maintain the biconcave shape of RBC. 9 Outer surface is covered by glycocalyx (call coat) which is responsible for blood grouping (A, B, AB, O) & Rh factor.  Number: Erythrocytic count is the number of erythrocytes per mm³ of blood  In male: 5 – 5.5 million/mm³ due to the stimulatory effects of male hormones on the bone marrow.  In female 4.5 - 5 million/mm³ due to menstruation and estrogen.  RBC count is highest in the newborns and decreases gradually. Abnormality in number of erythrocytes: 1. Anemia (oligocythemia): Decreased number of RBCs below 4 million/mm3 and/or decreased Hemoglobin concentration Types of anemia: Deficiency & Pernicious & Aplastic & Hemorrhagic & Hemolytic ; Pernicious anemia: (Vitamin B12 deficiency anemia) due to failed production of intrinsic factor by the stomach. ; Aplastic anemia: destruction of the bone marrow e.g. by irradiation or chemotherapy leading to pancytopenia (decreased count of all blood cells) ; Sickle cell anemia: an abnormal rigid type of Hb. called (HbS) that accumulates at one side of the cell giving a crescent shape (Sickle RBCs). 54 HISTOLOGY with ZAHRA Stain  BLOOD Chapter 4 2. Polycythemia: it is the increase in the number of RBCs above 6 millions/ mm3 Cause : due to hypoxia that stimulates the bone marrow. It may be: ; Physiological e.g. high altitudes, muscular exercise, newborns. ; Pathological e.g. chronic lung and heart diseases.  life span of erythrocytes: about 120 days  fate:  Old RBCs are phagocytosed by macrophages in the liver, bone marrow & spleen.  It is excreted as bile pigments while Iron is reused to form new RBCs  Osmotic Pressure (O.P): RBCs are osmotically fragile. They maintain their shape only in isotonic solution, (0.9% NaCl [saline] = O.P of plasma)  Crenation; in a hypertonic solution, they shrink and show notches.  Hemolysis; in a hypotonic solution, they swell, burst and leak hemoglobin. Leaving cell ghost.  Structure function adaptation of erythrocytes: Factor Mode of adaptation Plasticity (Flexible) to be squeezed inside narrow vessels. Plasma lemma Lipoproteins are highly selective for gas exchange Biconcave to increase surface area for gases exchange Shape Rounded edge for easy flow & passage in branched BVs. No nuclei or organelles → don’t divide and to give more space for Hb Content Contain enzymes (Hb. Reductase → combine with Hb. & carbonic anhydrase → carry CO2) HISTOLOGY with ZAHRA Stain 55 4 4 Chapter BLOOD LEUCOCYTES OR WHITE BLOOD CELLS (WBCS) They are true cells having nuclei and organelles.  Leucocytic count  Total leucocytic count : total number of WBCs/mm3 = 4000-11000 cell/mm³  Differential leucocytic count: the percentage% of each type to the total count  Abnormalities in total count:  Leukocytosis: ↑↑ total No.of WBCs > 11,000/mm3 due to. ; Physiological: pregnancy, labor, cold bath & exercise. ; Pathological: infections Clinical Note Leukemia: cancer with very high leucocytic count & abnormal and immature WBCs  Leukopenia; ↓↓ No. of WBCs < 4,000/mm3 due to: ; X-ray - irradiation ; some antibiotics e.g. chloramphenicol ; Typhoid fever ; Influenza virus  Life span: short life span, companstaed by new cell from blood stem cells of bone marrow WBCS GRANULAR NON-GRANULAR Neutrophils lymphocytes Eosinophils monocytes. basophils Bacterial infection → neutrophils neutrophils ‫ا كترهم فى العدد‬ Parasitic infection → eosinophils basophils ‫اقلهم فى العدد‬ Viral infection & chronic diseases → lymphocytes monocytes ‫أ كبرهم فى الحجم‬ Allergy → basophil - eosinophils small ‫أصغرهم فى الحجم‬ Acute inflammation → neutrophil lymphocytes Chronic inflammation → monocyte - lymphocyte 56 HISTOLOGY with ZAHRA Stain  BLOOD Chapter 4 1 Granular Leucocytes: 1- Neutrophils = Polymorphnuclear leucocytes = PMNLs = microphages  %: 60-70%  Shape : Rounded cells, Azure dye =  Diameterr:10-12 µm. methylene blue  Life span: few days  By LM: ; Nucleus:  Single - Multilobed (3:5 lobes) - segmented - dark - connected by chromatin strands. (many shapes)  Barr body seen in 3-6% of female cells. ; Cytoplasm: they show: 1. Specific granules: numerous, fine, pale granules. 2. Non specific (azurophilic granules): few large purple with azure dye.  By EM: ; Nucleus: Peripheral heterochromatin with small central euochromatin ; Cytoplasm:  Pseudopodia - Few organelles - more Glycogen (energy)  Two types of granules: Specific granules(2ry) granules: Non specific Azurophilic granules(1ry): ; Small - many - pale ; Large - few - dark. ; Contain ; lysosomes containing: 1. Phagocytin 1. Myeloperoxidase 2. Lysozyme 2. Defensins against bacteria & 3. Collagenase viruses 4. Lactoferrin. HISTOLOGY with ZAHRA Stain 57 4 Chapter BLOOD  Functions: First line of defense against bacteria. 1. Phagocytose bacteria: (microphages): ; First: by specific granules:  Lactoferrin: binds to iron [Bacteriostatic] Neutrophil  Phagocytin: kill bacteria [bactericidal] migration by  Lysozyme: destroys bacterial proteins. diapedesis  Collagenase: destroys collagen for movement of neutrophils ; Second: by non specific (azurophil granules):  Myeloperoxidase kill bacteria  other enzymes cause their lysis. 2. Dead neutrophils form pus cells. 3. Pus increases body temperature (pyrogen). 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.  Pathological increase: (neutrophilia) > 75% e.g.: acute pyogenic infections (tonsillitis - appendicitis – abscess).  Pathological decrease: (neutropenia) < 60% e.g.: Influenza virus - TB - typhoid fever. (common) Eosinophils Basophils % 1-4% 0-1% Diameter 10-14 µm 10-12 µm Life span Few days Few days Nucleus: Nucleus:  irregular, segmented, pale  bilobed or  S shaped.  horse-show Cytoplasm: LM  connected by thick chromatin  large basophilic granules strands masking the nucleus. Cytoplasm:  Metachromatically stained  large, acidophilic granules. with toluidine blue → purple (due to presence of heparin) 58 HISTOLOGY with ZAHRA Stain  BLOOD Chapter 4 Nucleus: Nucleus:  Peripheral heterochromatin  Minimal peripheral  More central euochromatin heterochromatin than neutrophil.  More central euochromatin. Cytoplasm: few organelles & two Cytoplasm: few organelles & two types of granules. types of granules: 1. Specific granules: 1. Specific granules:  oval  large, rounded.  electron dense core  electron dense contain EM (internum)& less dense 9 heparin. periphery (externum) 9 Histamine  contain: 9 eosinophil chemotactic 9 histaminase, factors. 9 sulphatase 9 leukotrienes. 9 neurotoxin 2. Few Non specific (Azurophilic 2. Non specific (Azurophilic granules): (lysosomes): granules): smaller - less. contain hydrolytic enzymes. lysosomes containing MCQ? Cell membrane shows hydrolytic enzymes. receptors for IgE. 1. Termination of allergic 1. Secrete Heparin prevents reaction clotting & promotes allergy a. Histaminase & sulphatase 2. Secrete Histamine destroy histamine & heparin. vasodilatation causing sudden b. Phagocytose the Ag-Ab ↓↓ in blood Pressure → Complexes anaphylaxis Function 2. Defense against parasites. 3. Attract eosinophils to site a. Cytotoxic effect of internum of allergy by Eosinophil forming pores in their chemotactic factor bodies. 4. Leukotrienes: Bronchospasm b. Neurotoxins causing nervous causing bronchial asthma. dysfunction of parasites 5. Limited phagocytic power > 5% > 2% 1. allergy → urticaria, eczema, 1. Allergic diseases. Increase bronchial asthma 2. Parasitic diseases. in number 2. parasitic infection → 3. Viral infection (chicken pox). Bilharziasis 4. Liver cirrhosis. Decrease < 1% in number Cortisone therapy ↓ Bone marrow HISTOLOGY with ZAHRA Stain 59 4 Chapter BLOOD  Comparison between Basophils and Mast Cell Basophils Mast cells Life span Few days Longer (weeks to months) Size 10-12 um 20-30 um the Nucleus Segmented Round Phagocytosis Slight No Granules Metachromatically stained due to (Histamine &heparin) Surface receptors: Antibody Ig E 60 HISTOLOGY with ZAHRA Stain  BLOOD Chapter 4 2 Non-Granular Leucocytes: 1. Lymphocytes (2nd common of WBCs & 2nd line of defense)  Number: 20-30% of total leucocytic count.  Types of lymphocytes according to Size: 1. Small lymphocytes: 2. Large lymphocytes: Inactive Active or NK cells % 15-20% 5-10% diameter 6-8 µm 10-15 µm Nucleus: Dark & filling the cell Nucleus: larger slightly indented, By LM: Cytoplasm: Little, pale pale with clear nucleolus basophilic rim around the Cytoplasm: abundant basophilic nucleus. Nucleus:. Euchromatic with Nucleus: heterochromatic prominent nucleolus Cytoplasm: Cytoplasm.: more organelles: 9 few mit., By EM: 9 mit., 9 small GA, 9 ribosomes, 9 many free ribosomes, 9 rER, 9 two centrioles 9 G.A. 9 small azurophil granules 9 lysosomes  Abnormalities in number:  Lymphocytosis: increase > 30% ; physiological in children. ; Chronic infections e.g. T.B & whooping cough. ; Leukemia.  Lymphocytopenia (pancytopenia): decrease < 20%  Motility & distribution:  Actively motile,  continuously circulating between the blood & lymphatic organs  They are the only cells which can return to blood.  Found in blood, lymph & lymphatic tissue. HISTOLOGY with ZAHRA Stain 61 4 Chapter BLOOD  Types of lymphocytes according to function: B lymphocytes T lymphocytes Natural killer cells % 20-30% 60-80% 5-10% bone marrow Thymus → acquire develop from precursors of T Maturation acquire receptors & B cells but do not mature in receptors (Thymic education) thymus Few days to Life span Years Years months Surface Ig receptors T cell receptors. CD16. receptors IgM, IgD (CD4 - CD8)  Innate Immune response. Humoral Cell mediated Function  Similar to T cytotoxic. immunity immunity  Antiviral (interferon). T lymphocytes (types & functions) 1-Cytotoxic CD8 T-cells (cell-mediated Immunity):  Secrete perforins that form pores in the cell membrane of the cells directly killing them.  Attack : virally infected cells – neoplastic cells – transplanted cells. 2-Helper CD4T-cells:  Activate B-lymphocytes. 3-Regulatory (Suppressor) T-cells:  Suppress the immune response to self-antigen.  Suppress excessive immune response. 4-Memory T-cells:  Rapid response of T-cells on re-exposure to same Ag (2ry immune response) B lymphocytes  activated by T- helper cells to Plasmablasts then plasma cells to produce antibodies. (Humoral immunity)  B memory cells responsible for the rapid 2ry immune response. HIV Human Immunodeficiency virus that causes AIDs destroys the T- helper cells suppressing immunity & the patient becomes susceptible to infections 62 HISTOLOGY with ZAHRA Stain  BLOOD Chapter 4 2. Monocytes  Number: 3-8%  Diameter: 13:20 µm (the largest).  Life span: 3 days in blood & 3 months in CT.  By L.M:  Nucleus: ; Large, eccentric, kidney-shaped, pale with 1 or 2 nucleoli  Cytoplasm ; non-granular ; non- clear ; Pale basophilic. ; frosted glass appearance due to lysosomes (azurophil granules).  By L.M:  Nucleus: Euchromatic with clear nucleolus  Cytoplasm : ; Have pseudopodia, ; well-developed G.A. in the concavity of the Nucleus. ; Many lysosomes (1ry & 2ry). ; rER- ribosomes – mitochondria.  Functions: Highly phagocytic cells: 1. Phagocytose bacteria & debris. 2. Antigen presenting cells. 3. The precursors of all phagocytic cells: e.g.  dust cells of lungs  Kupffer cells of liver  osteoclasts of bone  microglia of CNS. 4. Migrate to C.T → Macrophage  Monocytosis: Increase > 8% due to 1. chronic infections; T.B., syphilis & glandular fever 2. monocytic leukemia.  Monocytopenia (< 3%) : pancytopenia HISTOLOGY with ZAHRA Stain 63