Hematological System PDF

Hematological System Dr. Salmi Ab Aziz [email protected] School of Health Sciences  Blood - blood is 55% plasma and 45% formed elements (red cells, white cells, and platelets). Total Blood Volume: 8 % of body weight Centrifuged Blood Sample ...

Hematological System Dr. Salmi Ab Aziz [email protected] School of Health Sciences  Blood - blood is 55% plasma and 45% formed elements (red cells, white cells, and platelets). Total Blood Volume: 8 % of body weight Centrifuged Blood Sample  Components of Blood Plasma ▪ Plasma is the clear yellow liquid – mainly as the transportation in blood. ▪ It is mostly water - 91.5%. ▪ The rest is protein & solutes. The proteins in blood function primarily as clotting agents and antibodies. ▪ Albumins ▪ Globulins ▪ Fibrinogen ▪ Other proteins  Functions of Plasma 1. Water: * Transport medium 2. Electrolytes: * Osmotic distribution of fluid b/t ECF & ICF * Buffering of pH changes 3. Nutrients, wastes, gases, hormones:  transport Components of Blood https://araphily.com/?p=7723  Serum ▪ Plasma contains a range of proteins that help the blood to clot. ▪ Serum is the liquid that remains after blood is clotted. Functions of Blood https://araphily.com/?p=7723  Functions of Blood 1. Transport Transports dissolved gases, nutrients absorbed from the gut, and hormones, to all tissues and cells of the body. Carries O2 from the lungs and drops off CO2. It picks up nutrients from the digestive tract to deliver to the liver and other tissues. It carries hormones from endocrine glands to deliver them to target organs. Carries waste products to the kidneys, lungs, and other organs for excretion 2. Protection against blood loss Prevents excessive fluid losses through damaged vessels. Platelets and clotting proteins- Haemostasis.  Functions of Blood 3. Protection against infection Defends against pathogens and toxins. White blood cells help defend against infection. This process is called immunity. 4. Regulation – Homeostasis Blood regulates the pH and electrolyte composition of the body fluids. Buffers in the blood stabilize the pH of the fluid surrounding cells (extracellular fluid). Blood also regulates body temperature. Blood vessels in the skin are dilated (relaxed) or constricted so that heat from the body can be given off or conserved.  Blood Cells ▪ Blood cells are made from hemopoietic stem cells. ▪ The THREE (3) main cell types: - red cells - white cells - platelets  Red Blood Cells ▪ Shape - a biconcave disc with large surface area ▪ Can change shape ▪ No Nucleus / organelles ▪ Contains hemoglobin https://health.economictimes.indiatimes.com/news/diagnostics/red-blood-cell-alterations- contribute-to-lupus-study/85301320 Primary Function = Transport oxygen from the lungs to the cells of the body & assist with CO2 removal  Mechanism of Transport HEMOGLOBIN 4 Heme Molecules = 4 Oxygen Molecules https://www.expertart.net/?s=blood+transport  Red Blood Cells ▪ Lack intracellular organelles necessary for cellular repair, growth, division ▪ Short Life Span (~120 days)  Aged RBC  Fragile - prone to rupture ▪ Ruptured RBC’s are destroyed in spleen  Phagocytic WBC’s “clear the debris”  Formation of new RBC http://www.medicinehack.com/2011/05/red-blood-cell-formation.html https://pediaa.com/difference-between-cord-blood-and-cord-tissue/ ▪ Anemia – low hb (below-normal oxygen-carrying capacity of the blood)  Nutritional, pernicious, aplastic, renal, hemorrhagic, hemolytic ▪ Polycythemia- abnormally high hematocrit (too many RBCs in circulation)  Primary, secondary  White Blood Cells ▪ Body’s defense system: ▪ Functions: - Destroy invading microorganisms - Destroy abnormal cells (ie:cancer ) ▪ Clean up cellular debris (phagocytosis) - Assist in injury repair https://www.sciencephoto.com/media/1062422/view/white-blood-cells-illustration Blood Origin and Production https://pediaa.com/difference-between-cord-blood-and-cord-tissue/  Neutrophils ▪ 50-70% of all leukocytes (most abundant of WBC’s) ▪ Important in inflammatory responses ▪ Phagocytes that engulf bacteria and debris  Eosinophils ▪ 1- 4% of the WBC’s ▪ Attack parasitic worms ▪ Important in allergic reactions  Basophils ▪ 0.5% of the WBC’s ▪ Release histamine and heparin ▪ Important in allergic reactions ▪ Heparin helps clear fat from blood  Monocytes ▪ 2-6 % of the WBC’s ▪ Exit blood to become macrophages ▪ Phagocytic = defend against viruses and bacteria  Lymphocytes ▪ 25-33 % of the WBC’s ▪ B-lymphocytes: Produce Antibodies ▪ T-lymphocytes: Directly destroy virus- invaded cells and cancer cells  Platelets (Thrombocytes) ▪ Cell fragments bound to megakaryocytes ▪ “Bud Off” and are released into the blood  Function of Platelets ▪ Stop bleeding from a damaged vessel * Hemostasis ▪ Three Steps involved in Hemostasis 1. Vascular Spasm 2. Formation of a platelet plug 3. Blood coagulation (clotting)  Steps in Hemostasis ▪ DAMAGE TO BLOOD VESSEL LEADS TO: 1. Vascular Spasm: Immediate constriction of blood vessel Vessel walls pressed together – become “sticky”/adherent to each other Minimize blood loss  Steps in Hemostasis 2. Platelet Plug formation: a. PLATELETS attach to exposed collagen b. Aggregation of platelets causes release of chemical mediators (ADP, Thromboxane A2) c. ADP attracts more platelets d. Thromboxane A2 (powerful vasoconstrictor) * promotes aggregation & more ADP Leads to formation of platelet plug ! (+) Feedback promotes formation of platelet Plug !  Final step in Hemostasis 3. Blood Coagulation (clot formation): “Clotting Cascade” a. Transformation of blood from liquid to solid b. Multiple cascade steps in clot formation c. Fibrinogen (plasma protein) to Fibrin  Clotting Cascade Fibrin :  Threadlike molecule-forms the meshwork of the clot  Entraps cellular elements of the blood forms CLOT  Contraction of platelets pulls the damaged vessel close together  Clot Dissolution ▪ Clot is slowly dissolved by the “fibrin splitting” enzyme called Plasmin ▪ Plasminogen is the inactive pre-cursor that is activated by Factor XII (Hageman Factor) (simultaneous to clot formation) ▪ Plasmin gets trapped in clot and slowly dissolves it by breaking down the fibrin meshwork  Clot Formation ▪ Too much:  Inappropriate clot formation is a thrombus (free- floating clots are emboli)  An enlarging thrombus narrows and can occlude vessels ▪ Too little:  Hemophilia- too little clotting- can lead to life- threatening hemorrhage (caused from lack of one of the clotting factors)  Thrombocyte deficiency (low platelets) can also lead to diffuse hemorrhages  BLOOD Can you?  State the composition of Blood  State the function of red blood cells and plasma  Explain the function of haemoglobin  State the function of neutrophils and lymphocytes THANK YOU… For your kind attention