CHI335 - Blood Circulation PDF

CHI335 Diagnosis I Learning Outcomes  Describe haematopoiesis, identify the components of blood, and their functions  Describe the components of plasma and their functions  Compare and contrast the various types of anaemia and their management  Discuss the various condition...

CHI335 Diagnosis I Learning Outcomes  Describe haematopoiesis, identify the components of blood, and their functions  Describe the components of plasma and their functions  Compare and contrast the various types of anaemia and their management  Discuss the various conditions caused by changes to white blood cell and platelet function, including leukaemia, thrombocytopenia, etc. Learning Outcomes  Outline the factors that are believed to contribute to polycythaemia  Explain the steps of Haemostasis and its disorders  Explains some common forms of coagulopathies, such as haemophilia  Differentiate between the presentation of haemophilia and von Willebrand disease  Describe and explain disorders with circulation Introduction  Blood represents life when…  Takes oxygen and nutrients to tissues  Takes Carbon dioxide and wastes away from tissues  Transport hormones  Regulates heat  Circulation  Process of transporting blood to and from the body tissues Blood  4 to 6 litres of blood in the human body  A connective tissue since it has a nonliving matrix and living cells  Plasma is the nonliving fluid component of blood  Cellular Components of Blood are the cells and cell fragments  Erythrocytes (red blood cells, RBCs)  Leukocytes (white blood cells, WBCs)  Thrombocytes (platelets) Haematopoiesis  Formation of blood cells from stem cells  During foetal development  RBCs are made in the yolk sac, the liver, and the spleen  After birth  Most blood cells are produced in red bone marrow by stem cells called haemocytoblasts Haematopoiesis Haematopoiesis  Erythropoietin  Regulates erythropoiesis, production of RBCs  Produced by the kidneys when oxygen concentrations in the blood get low (late compensation)  Vitamin B12 and folic acid for DNA replication & cell division  Iron is necessary to make haemoglobin  Iron-deficiency anaemia Blood Sample & Blood Smear Centrifuged sample of blood  The percentage of RBCs in relationship to the total blood volume is called the haematocrit  Normal haematocrit is about 37 to 43 percent in females and 43 to 49 percent in males  On top of the RBCs is the plasma  Between is a thin layer that is whitish in colour and is referred to as the “buffy coat”  White blood cells and platelets Plasma  Liquid portion of blood  Nutrients  Amino acids, glucose, nucleotides, and lipids that have all been absorbed from the digestive tract  Lipids must be combined with protein molecules to be transported by plasma (lipoproteins)  Different types of lipoproteins are chylomicrons, very low- density lipoproteins (VLDL), low-density lipoproteins (LDL), and high-density lipoproteins (HDL) Plasma  Gases  Dissolved in plasma  Oxygen, carbon dioxide, and nitrogen  Electrolytes  Dissolved in the plasma  Sodium, potassium, calcium, magnesium, chloride, bicarbonate, phosphate, and sulphate  Non-protein nitrogenous substances  Urea and uric acid Plasma Proteins Cellular Components of Blood RBCs  Small cells that have a biconcave shape  Mature RBCs do not have a nucleus  Contain a pigment called haemoglobin whose function is to bind to oxygen and transport it  Haemoglobin that carries oxygen is called oxyhaemoglobin and is bright red in colour  Carbaminohemoglobin refers to haemoglobin that carries carbon dioxide  Carboxyhaemoglobin is a stable complex of carbon monoxide and haemoglobin RBCs  A normal RBC count is about 4 – 6 million erythrocytes per cubic millimetre of blood Normal haemoglobin  Adult haemoglobin (HbA) molecule Source: Adapted from Martini & Nath (2009), Figure 19.3. RBCs  The average life span of an erythrocyte is approximately 120 days  Old RBCs are filtered out by macrophages in the liver and spleen  Haem is recycled to be used again in new RBCs  Globin is metabolised into biliverdin which is then converted to bilirubin in the liver  Bilirubin is used to make bile, a substance that emulsifies or breaks apart fat molecules Anaemia  Indicates a reduced oxygen-carrying capacity  Is a constellation of signs and symptoms but not a diagnosis  Anaemia is confirmed by measuring the level of haemoglobin  Normal Hb level in men is 14 to 18 gr/dl – must know  Normal Hb level in women is 12 to 16 gr/dl – must know  Presentation  Next slide… Anaemia – Presentation Anaemia – Aetiology  Altered production of red cells or haemoglobin  Loss of blood  Increased erythrocyte destruction  A combination of these Anaemia – Aetiology RBC morphology & Anaemia  Prefix  Examples  Micro- = small  Normochromic: normal in  Normo- = normal colour  Macro- = big  Hypochromic: light in colour  Hypo- = low  Normocytic: normal size cell  Microcytic: small cell  Suffix  Macrocytic: big cell  Chromic = colour  Cytic = cell Anaemia  Classified by RBCs’ size  Microcytic anaemia  e.g. iron-deficiency anaemia and thalassaemia  Macrocytic anaemia  e.g. pernicious anaemia and folate-deficiency anaemia  Normocytic anaemia  e.g. aplastic, haemolytic and anaemia of chronic disease Anaemia by RBCs’ size Iron-deficiency anaemia (IDA)  Often secondary to dietary deficiencies  Occasionally, due to malabsorption disorders  Individuals susceptible to iron-deficiency anaemia  People living in chronic poverty  Pregnant women  Females with Menorrhagia  People with ulcers or conditions associated with chronic blood loss  Haemorrhage can lead to a depletion in body iron stores (e.g. chronic blood loss, associated with bleeding lesions within the GIT), resulting in iron-deficiency anaemia Vit B12 & folate-deficiency anaemia  A deficiency in vit B12 or folate will cause anaemia  Vitamin B12 and folic acid are required for DNA synthesis and cell division  Because of enough B12 stores in the liver, this disorder has a slow, insidious onset that can take 2 years for symptoms to manifest  Folate deficiencies are mainly associated with malnutrition/poor diet, increased demand, and alcoholism Pernicious anaemia  Is an AI disease: Auto-antibody against Intrinsic Factor (IF) required for absorption of vit B12 from the diet Aplastic anaemia  An anaemia due to bone marrow destruction  e.g. Chemotherapy and radiation therapy, some cancers and toxins Sickle cell anaemia  A genetic disorder which leads to a malformation of erythrocytes into the characteristic sickle shape Sickle cells cannot transit capillary beds and Creates multiple blood flow obstructions leading to Significantly  O2 supply and Multiple micro-infarcted centres in the tissues Sickle cell anaemia  These affected cells are rigid, fragile and prone to breakage Source: © University of Alabama at Birmingham, Department of Pathology. Polycythaemia  An overproduction of red cells leading to  Abnormal high RBCs and haemoglobin  Increase in blood viscosity  Therefore, a greater risk of thrombosis & thromboembolism  Secondary polycythaemia  Is a physiological response to hypoxia, which causes secretion of erythropoietin →  production of erythrocytes   likelihood of developing secondary polycythaemia  Chronic obstructive pulmonary disorder (COPD)  Congestive heart failure  Living at high altitudes Primary Polycythaemia Aka polycythaemia vera or rubra vera  A rare condition marked by  production of erythrocyte, white cell and platelet + splenomegaly  The greatest concern is  blood viscosity  Blood flow becomes sluggish   thrombus formation  Occlusion of blood vessels of virtually all sizes  Marked tissue and organ ischaemia and infarction  Reasons for death in primary polycythaemia  CVA (more common)  MI WBCs  Categorised into two groups based on whether they have granules in their cytoplasm  Granulocytes  Neutrophils, eosinophils, and basophils  Agranulocytes  Monocytes and lymphocytes  All leukocytes contain a nucleus WBCs  Neutrophils (60%)  They have phagocytic capabilities  Destruction of bacteria  Their number increase in the early stage of acute inflammation  Eosinophils (3%)  Fight parasitic infections  Their number also increased acute or active allergies  Basophils (