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BLOOD. BLOOD AND ITS ASSOCIATED DISORDERS. Blood is a specialized body fluid that circulates in the blood vessels bringing oxygen and nourishment to all the cells and carrying away waste like carbon di oxide. Composition of blood
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BLOOD AND ITS ASSOCIATED DISORDERS • Blood is a specialized body fluid that circulates in the blood vessels bringing oxygen and nourishment to all the cells and carrying away waste like carbon di oxide. Composition of blood • Blood cells (45%) like Erythrocytes(RBC), Leucocytes(WBC) , Platelets(THROMOBOCYTES) All blood cells are produced in the bone marrow (haematopoises) some mature in the lymphoid organs • Plasma (55%)– constitutes about 90% of water , remaining 10% contains nutrients, electrolytes, gases, albumin (protein), clotting factors, antibodies, enzymes and hormones . • Normal blood volume is 5 ltrs
Erthrocytes (red blood cells) • Major function is to carry oxygen to the tissues • Oxygen is bound to iron containing pigment called hemoglobin(imparts red color to the blood) • RBC are biconcave or disc shaped having no nucleus • There are 5 millions RBC per microlitre of blood • These cells die after 120 days
Leucocytes • White blood cells (WBC) • They have a prominent nuclei Types • Granulocytes- have visible granules • Agranulocytes - do not show any visible granules Three types of granulocytes • Neutrophils- also called polymorphs (because of their various shaped nuclei) • Eosinophils • Basophils • Two types of agranulocytes • Lymphocytes • Monocytes
Relative percentage of WBC • Neutrophils- 54-62%- responsible for bulk of immuno response. Main components of pus and responsible for its whitish colour. • Eosinophils– 1-3%- mediates allergic reactions, defense against parasites • Basophils – less than 1%- mediates allergic reactions • Lymphocytes- 25-38%- renders immunity • Monocytes – 3-7%- help in immune system. (low monocyte is good and high indicates a problem in the patient) • TOTAL WBC COUNT=4500-11000 millions per litre
Platelets • Fragments of small cells called megakaryocytes • Formed in the bone marrow • Normal count – 150,000 to 350,000 per microliter of blood • Plays an important role in hemostasis- (prevention of blood loss) • One of the process of hemostasis is called coagulation • Platelets form a plug at the site of vessel injury and release some substances that react with coagulation factors and seal the wound • Coagulation factors are 12 in number • Final reaction in coagulation is conversion of fibrinogen to fibrin threads to form a clot
Blood groups • Human blood groups fall into four main groups- A ,B ,AB, O • Each group has a specific combination of antigen(on RBC cell membrane) and associated antibodies • Antigens are inherited while antibodies are acquired by 6 months of birth • Group A –antigen A ,anti-B antibody • Group B- antigen B,anti- A antibody • Group AB-antigen AB, no antibodies • Group O- has no antigens,has both anti-A &B antibodies • People with group O are universal donors as they lack antigens, while group AB are universal recipients as they lack antibodies
Clinical aspects of blood I Anaemia • It is defined as condition characterised by low amount of hemoglobin in the blood • Anaemia can result from decreased RBC count or small cell size or little hemoglobin Different types of anaemia • A. Anaemia due to decreased blood count • EG: Aplastic anaemia – results from bone marrow destruction causes - Drugs ,Radiation, Viruses ,Toxins, Bone marrow cancers • B. Nutritional anaemia (iron deficiency) • Results from deficiency of vitamin B12 or folate needed for RBC development • Causes - Poor diet ,pregnancy, low iron absorption
C. Pernicious anaemia- results from specific form of Vit B12 deficiency • D. Sideroblasticanaemia- results from non utilisation of iron inspite of availability, secondary to any disease • E. Hemolytic anaemia- reduction in RBC due to excessive destruction of RBC. Congenital spherocytosis
F. Anaemia due to loss or destruction of RBC • Hemorrhagic anaemia – results from excessive blood loss-acute or chronic • Thalassemia –(thalassa means sea) occurs in mediterranian population • It is a heriditary disorder characterised by production of abnormal hemoglobin • G. Sickle cell anaemia- is a mutation altering the hemoglobin molecule resulting in sickle shape of the RBC .
II Hemophilia • Hereditary deficiency of clotting factor (factor viii) • Sex linked that passes from mother to son • There is presence of bleeding in the tissue • Can be treated with administration of required fractions of clotting factors
Neoplasms A. Leukaemia– It is the neoplasm of WBC. • White cells divide rapidly and accumulate but are incompetent Symptoms • Anaemia, fatigue, bleeding,splenomegaly, hepatomegaly B. Multiple myeloma • Cancer of blood forming cells in the bone marrow, mainly plasma cells that produce antibodies • Patient with multiple myeloma suffers from infections due to immunodeficiency • Treated with radiation and chemotherapy