Blood (2020) - Histology Lecture Notes PDF

MSc, Manchester University, UK Department of Histology Faculty of Medicine Tripoli University Dr. Hana Abusaida 1 2020 BLOOD ( specialized C.T.) Definition: specialized C.T. (vi...

MSc, Manchester University, UK Department of Histology Faculty of Medicine Tripoli University Dr. Hana Abusaida 1 2020 BLOOD ( specialized C.T.) Definition: specialized C.T. (viscous fluid). Site: in blood vessels and bone marrow. Origin: Mesenchyme Volume: 5 liters in healthy adult human. Mesurment: A cubic millimeter of blood is equivalent to a microliter (L). Functions Transport of: Gases, nutrients, waste products Regulation of pH and osmosis Maintenance of body temperature Protection against foreign substances Clot formation  Blood transporting O2 & CO2, metabolites, hormones, and other substances to cells throughout the body.  O2 is bound to hemoglobin in erythrocytes, while CO2 is carried in solution as CO2 or HCO3– Dr. Hana Abusaida 2 Blood Composition plasma (55%) + cells (45%). Dr. Hana Abusaida 3  Composition of whole blood Hematocrit Is the volume percentage of RBCs in the blood.  A tube of blood after centrifugation: has about 43% of its volume is erythrocytes in the bottom half of the tube, a volume called the hematocrit.  It is normally 47% ±5% for men  42% ±5% for women. buffy coat  Between the erythrocytes and the upper light- colored plasma is a thin layer of leukocytes and platelets called the buffy coat. Dr. Hana Abusaida 4  Blood film to study cells 1. Clean 7- Leishman stain: ( mixture of ): 2. Prick.  Eosin (acidic or eosinophilic) ( red ). 3. Put drop on clean dry slide.  Methylene blue (basophilic). 4. Put another slide on 45o  azures (purple) for cytoplasmic granules. 5. Move backward to touch drop 6. Move forward to spread drop. Dr. Hana Abusaida 5 Blood Platelets film RBC Lymphocyte Neutro phil Dr. Hana Abusaida 6  1- Plasma  Comprising 55% at the top half of the centrifugation tube  Yellowish fluid.  is an aqueous solution, pH 7.4 Composition: 1- Water (92%). 2- Plasma proteins (7%):  Albumin for osmotic pressure  Globulin for antibodies  Fibrinogen for coagulation 3- Organic and inorganic substances (1%) Dr. Hana Abusaida 7  2- Blood cells (formed elements ) 1- Red blood cells (RBCs) or Erythrocytes. 2- White blood cells (WBCs) or Leukocytes. 3- Platelets or Thrombocytes. 8 Dr. Hana Abusaida  Red blood cells Names : Red blood corpuscles. ERYTHROCYTES. RBCs Characters: Rounded, biconcave discs, 7.5 µm diameter, 2.6 µm thick at the rim, 0.75 µm thick in the center Non nucleated, No organells ( non true cell). Non motile. Suspended in an isotonic medium plasma. Soft and plastic → change shape in capillaries. In small vessels they are aggregated and called Rouleaux. Life span about 120 days. Dr. Hana Abusaida 9  Red blood cells Poikilocytosis (Abnormal shapes)  As in Sickle cell anaemia. Number of RBCs:  Sickle cell anemia is an inheritid 1- Normal: disease in which production of male (5-5.5 millions/mm3). abnormally shaped red blood cells female (4.5-5 millions/mm3). ( sickle shape). 2- Increase: Polycythaemia (Erythrocytosis) a- Physiological: in individuals who live at high altitudes (where O2 tension is low). b- Pathological: congenital heart & hypoxic lung. 3- Decrease: Anemia Dr. Hana Abusaida 10  Structure of RBCs Cell membrane, Consists of : 40% lipid, 10% carbohydrate, 50% protein Cytoskeletons for maintained shape. Aantigens on the surface determine blood group (A, B, O and Rh). Dr. Hana Abusaida 11  Relations of RBCs size to osmotic pressure 1- In isotonic solution (plasma) osmotic pressure of plasma = in RBCs. 2- In Hypertonic solution water flow from low solute in the cell to high out the cell ), (water leaves cells → shrink, (crenation). 3- In Hypotonic solution (water accumulate in cells → swelling (haemolysis). Size of RBCs Normocyte: 6-9 um (7.5). Macrocyte: larger than 9um. Microcyte: smaller than 6um. Anisocytosis: high % erythrocytes & great variations in size 12 Dr. Hana Abusaida  Hemoglobin (Hb) Hemoglobin: Is a protein in the cytoplasm of red blood cells ( Haem 4% + Globin 96% ) Normal: 15.5 gm/L in males. 14 gm/L in females.  Hb normal: normochromic.  less than normal: hypochromic.  Hb more than normal: hyperchromic. Hemoglobin is: O2 carrying protein from lungs to tissues of the body. The heme is pigments contain iron. Dr. Hana Abusaida 13  Anemia Adaptation to function Causes of anemia: 1-Biconcave discs → increase 1- Decreased number of RBCs: surface area to facilitate gas  A plastic anemia: bone marrow defect, infants are born exchange. without the ability to make 2- Plastic → compress in narrow enough red blood cells.  capillaries. Haemorrhagic: blood loss. 3- No nuclei or organelles → space 2- Decreased HB. for Hb. 3- Decreased hemopoietic factors 5- Glucose metabolism enzymes → (iron & vitamin B12). 4- Haemolysis ( breakdown of energy. RBCs ). Dr. Hana Abusaida 14  Leucocytes, WBCs Names  Leucocytes.  White blood cells.  WBCs. Characters:  True cells ( with nucleus + organelles),  Originate in bone marrow.  Spherical while suspended in blood plasma,  become amoeboid and motile after leaving the blood vessels and invading the tissues. Dr. Hana Abusaida 15  Types of leucocytes 1- Agranulocytes. ( mononuclear ) Contains non-specific granules only. – Lymphocytes. – Monocytes. 2- Granulocytes ( polymorphonuclear ) Contains specific and non-specific granules – Neutrophils. – Eosinophils. – Basophils. Dr. Hana Abusaida 16 Dr. Hana Abusaida 17  Granular leucocytes Two types of granules: Non-specific (azurophilic ) i.e, lysosomes, M stain darkly, present in all leukocytes. B Specific, that bind neutral, basic, or acidic L stains and have specific functions. N Three types according to stain of specific granules: Neutrophils: neutral. Eosinophils: acidophilic. N Basophils: basophilic. E Differential leucocytic count (DLC) (Percentage of each type of leucocytes). 1. Granular leucocytes: 2. Non-granular leucocytes: – Neutrophils, 60-70%  Lymphocytes, 20-40% – Eosinophils, 1-4%  Monocytes, 2-8% – Basophils, 0-0.5% Dr. Hana Abusaida 18  E N M N M L L B Dr. Hana Abusaida 19  1- Neutrophils Nucleus :, 2-5 lobes granules: 1-Specific granules, Neutral, Small, numerous. 2-Non-specific granules ( azurophilic granules): Large, few, lysosomes. Immature neutrophil with horse-shoe nucleus (band forms). Neutrophils are short-lived cells with life span of 6–7 hours in blood , and a life span of 1–4 days in connective tissues before dying by apoptosis. Dr. Hana Abusaida 20  Neutrophils Functions of neutrophils: Engulf bacteria by phagocytosis: They are Inactive , spherical while circulating in the blood but become actively amoeboid during diapedesis. Diapedesis, passage of neutrophils, through blood vessel walls to the tissues. The process of the first leukocytes to arrive at sites of infection is named chemotaxis. Dr. Hana Abusaida 21  2- EOSINOPHILS 2–4% of leukocytes. Nucleus: bilobed horse-shoe. abundance of large, red specific granules stained by eosin. EM: Cytoplasm: 2 types of granules. 1. Specific: Oval with central crystalline dense core contain major basic protein (MBP) , peroxidase enzyme → cytotoxic effects on parasites (chemical attack), control mechanisms associated with allergy and asthma. 2. Non-specific: lysosomes. Dr. Hana Abusaida 22  MEDICAL APPLICATION Eosinophilia Is an increase in the number of eosinophils, Often indicates a parasitic infection, an allergic reaction or cancer. eosinophils are found in the C.T. underlying epithelia of the bronchi, gastrointestinal tract, uterus, and vagina, and surrounding any parasitic worms present. In addition, these cells produce substances that modulate inflammation by inactivating the leukotrienes and histamine produced by other cells. Dr. Hana Abusaida 23  3- BASOPHILS less than 1% of WBCs. Nucleus is U or S shape. largest specific granules (0.5 m in diameter) (basophilic). Azurophilic non-specific granules stain dark blue or metachromatically The metachromasia is due to the presence of heparin and glycosaminoglycans (GAGs) in the granules. Dr. Hana Abusaida 24 Comparison of basophil and eosinophil in a blood smear Eosinophil Basophil Dr. Hana Abusaida 25  4- LYMPHOCYTES Types: 1. T-lymphocytes. 2. B-lymphocytes. 3. Natural-killer (NK) cells. Types of T- lymphocytes: a. Large : only in lymphatic tissues. b. Medium: 8% in blood. c. Small 6-8um size: 90% predominate in blood. Small lymphocyte Dr. Hana Abusaida 26  Origin of lymphocytes In bone marrow: cells staying in bone marrow differentiate into B lymphocytes. cells migrating to thymus differentiate into T-lymphocytes. – B-lymphocytes (B-cells): When stimulated by specific antigen differentiate into plasma cells which produce antibodies. – Some B-cells become memory cells. – T-lymphocytes (T-cells): cytotoxic T cells and helper T cells. B-lymphocytes:  Life span: 3 month. Function: humoral immunity. Dr. Hana Abusaida 27  Natural-killer (NK) cells. Are cytotoxic lymphocyte. 5% of small lymphocytes. provide rapid responses to viral-infected cells and respond to tumor formation, acting at around 3 days after infection. Dr. Hana Abusaida 28  5- MONOCYTES Nucleus is large, off-center, kidney or U –shaped. Cytoplasm is basophilic, contains very small azurophilic granules (lysosomes). Originated from bone marrow. circulate in blood few days. leave blood to C.T and differentiate into macrophages. Dr. Hana Abusaida 29  Function of monocytes Phagocytosis. Monocytes differentiate into: Macrophages in connective tissues, Microglia, phagocytotic cell in the CNS, Dust cell in respiratory system Osteoclasts in bone. MEDICAL APPLICATION Monocytosis: An abnormal increase in the number of monocytes in the blood during chronic inflammation. Dr. Hana Abusaida 30  Total leucocytic count (TLC) Total number of leucocytes.is 4,000 – 11,000 / mm3 of blood Leukocytosis Increase TLC, more than 11,000/mm3 of blood. Types: Physiological: pregnancy. Pathological: acute inflammation. Leucopenia Decrease TLC, below 4,000/mm3of blood, Pathological. leukaemia is a type of cancer begins in the bone marrow, abnormal increase of immature white blood cells"( blasts or leukemia cells ), are not fully developed cells." Dr. Hana Abusaida 31  Agranulocytes Granulocytes Monocyte Lymphocyte Basophil Eosinophil Neutrophil 2-8 20-40 0-0.5 1-4 50-70 % Few days 3M - years Few days (7) (8-12) (12-15) Life span 20 largest 7-8, 12-18 10-12 um Diameter Basophilic Largest basophilic Larger small numerous Cytoplasm non-specific granules by EM specific granules acidophilic specific granules similar to mast elongated + large cell granules. specific few non-specific granules non-specific granules with granules (lysosomes). crystalloid (lysosomes). core. non-specific granules (lysosomes) Kidney shaped Large rounded S-shape Horse-shoe Multilobulated Nucleus Bilobulated Phagocytic Immunity Allergy(Histamie Cytotoxic , Phagocytic Function and Heparin) Allergy Dr. Hana Abusaida 32 Dr. Hana Abusaida 33  BLOOD PLATELETS (Thrombocytes) Non-nucleated (not true cells), oval or disk like cell. 2–4 um in diameter. Origin: from megakaryocytes ( giant cell) in the bone marrow. Normal platelet counts from 200,000 to 400,000/mm3 of blood. Life span 5-10 days. Structure: – Peripheral zone, the hyalomere, – Central zone,called the granulomere. Dr. Hana Abusaida 34  Platelets Structure: Platelets has two zones: 1- Peripheral zone( hyalomere ),  A coat rich in GAGs and glycoproteins lies outside the plasmalemma and is involved in platelet adhesion.  Marginal bundle of microtubules and microfilaments (actin,myosin) which helps to maintain the platelet's ovoid shape.  two membranes: 1. open canalicular system , vesicles facilitate platelets' uptake of factors. 2. dense tubular system is derived from the ER and stores Ca2+ ions. 2- Central zone ( granulomere) : Mitochondria, glycogen and granules: 1. Alpha: proteins (clot factors). 2. Delta: calcium, enzymes (e.g.Serotonin). 3. Lambda: lysosomes. Dr. Hana Abusaida 35 Platelets structure Dr. Hana Abusaida 36  Platelets Functions: - Control of haemorrhage (bleeding). - Promote blood clotting. Clot factors: 1. Fibrinogen. 2. plasminogen. 3. thromboplastin. Dr. Hana Abusaida 37 The role of platelets in controlling hemorrhage: 1- Primary platelet aggregation: platelets adhere together forming → plug platelets. 2- Secondary platelet aggregation: release glycoproteins → increase plug size. 3- Blood coagulation:( Form of blood clot ). Release of coagulation factors, produce → fibrin protein. network of fibrin trap blood cells forms blood clot. 4- Clot retraction: Clot contraction due to the interaction of platelet actin and myosin. 5- Clot removal: the vessel wall is restored by new tissue, then clot removed by plasma proteolytic enzymes (plasmin, plasminogen ) and lambada granules (lysosomal enzymes). Dr. Hana Abusaida 38 Blood clot: Dr. Hana Abusaida 39  MEDICAL APPLICATION Hemophilia Severe haemorrage after injury. Inherited genetic X- chromosome disorder , disease transimtted by female X-Chromosome. People born with hemophilia have little or no clotting factors. Dr. Hana Abusaida 40  Thank you from D. Hana Dr. Hana Abusaida 41