Blood Function & Composition PDF

BLOOD Functions: 1. Transport of gases, nutrients, waste products, processed and regulatory molecules 2. Regulation of pH and osmosis 3. Maintenance of body temperature 4. Protection against foreign substances 5. Clot formation Composition of Blood: ​ Plasma ​ 55% of total blood ​ Pale, yell...

BLOOD Functions: 1. Transport of gases, nutrients, waste products, processed and regulatory molecules 2. Regulation of pH and osmosis 3. Maintenance of body temperature 4. Protection against foreign substances 5. Clot formation Composition of Blood: ​ Plasma ​ 55% of total blood ​ Pale, yellow liquid surrounding cells ​ 91% water, 7% proteins, and 2% others Formed elements: (Solid Structures) ​ 45% of total blood ​ Cells and Cell fragments ​ Erythrocytes (RBCs), Leukocytes (WBCs), Thrombocytes (Platelets) PLASMA PROTEINS 1. Albumin ​ 58% of plasma proteins ​ Helps maintain water balance (osmotic pressure) 2. Globulins ​ 38% of blood proteins ​ Helps immune system 3. Fibrinogen (Fiber) ​ 4% of blood proteins ​ Aids in clot formation ​ Activation of clotting factors results from conversion of fibrinogen to “fibrin” ​ Fibrin, threadlike protein responsible for blood clots PLASMA VS SERUM Plasma ​ Liquid portion of unclotted blood ​ Albumin, Globulin, and Fibrinogen ​ Obtained by using anticoagulant Serum ​ Liquid portion of clotted blood  ​ Consists of albumin and globulin only ​ Plasma without the clotting factors HEMATOPOIESIS ​ Process the produces formed elements ​ In the fetus, it occurs in several tissues such as liver, thymus, spleen, lymph nodes, and red bone marrow ​ After birth, it occurs primarily on the red bone marrow, but some white blood cells are produced in lymphatic tissues ​ All formed elements of blood derived from a single population of cells called “Hemocytoblasts” (stem cell) ○​ They differentiate to give rise to different cell lines: ​ “Myeloid” stem cell ​ “Lymphoid” stem cell (Matures only into Lymphocytes) ERYTHROCYTES (Red blood Cells/ RBCs) ​ Disk-shaped with thick edges/bio concave disk (thicker than the center) ○​ The increases the RBC’s surface area thus allowing gases to move in and out rapidly out of that cell ​ Nucleus and most organelles lost during development (to have more space for hemoglobin to have more areas to carry oxygen) ​ Lives for 120 days (males) and 110 days (Females) ​ Unable to divide ​ Transports oxygen from lungs to tissues HEMOGLOBIN ​ Main component of erythrocytes (RBC’s) constituting one-third of RBC’s volume ​ Transports 98.5% of oxygen in the body and Carbon dioxide for excretion ○​ Remaining 1.5% is dissolved in plasma ○​ Oxygenated: Bright red ○​ Deoxygenated: Dark red ​ Each hemoglobin molecule consists of 4 protein chains (globin) and 4 heme groups ​ Each “globin” protein is bound to one “heme” molecule (red pigmented molecule) ○​ Each “heme” contains one iron atom (necessary for function of hemoglobin) ​ Oxyhemoglobin ○​ Hemoglobin with oxygen attached ​ Carboxyhemoglobin ○​ Hemoglobin with carbon monoxide attached ​ Carbon monoxide ○​ Helps transport Carbon dioxide from tissues to lungs (Oxygen transport is accomplished by hemoglobin) ○​ Gas produced by incomplete combustion of hydrocarbons (gasoline) ○​ Binds to iron in hemoglobin 210x more readily than oxygen and does not tend to unbind which makes hemoglobin bound to carbon monoxide no longer capable of transporting oxygen  ○​ Nausea, headache, unconsciousness, and death are possible consequences of prolonged exposure to carbon monoxide. PRODUCTION OF ERYTHROCYTES 1.​ Decreased blood Oxygen levels causing kidneys to increase production of hormone erythropoietin 2.​ Erythropoietin stimulates red bone marrow to produce more erythrocytes 3.​ Increased erythrocytes cause an increase blood oxygen levels FATE OF OLD ERYTHROCYTES AND HEMOGLOBIN 1.​ Old/abnormal/damaged RBCs are removed from blood by macrophages in the spleen and liver. 2.​ Hemoglobin is broken down. 3.​ Globin is broken down into amino acids. 4.​ Hemoglobin’s iron is recycled. 5.​ Heme is converted to bilirubin (yellow pigment molecule and can be deposited to other tissues resulting in “jaundice”, yellowish color to the skin/abnormal functioning of liver). 6.​ Bilirubin is taken up by the liver and released into the small intestine as part of bile. LEUKOCYTES (White Blood Cells/ WBCs) ​ Lacks hemoglobin ​ Larger than erythrocytes (RBCs) ​ Contains a nucleus ​ Can leave the blood and travel by “ameboid” (movement through tissues) ​ Fights off infections ​ Removes dead cells and debris by “phagocytosis” Types of Leukocytes 1.​ Granulocytes - contains large cytoplasmic granules/specific granules ​ Neutrophils ○​ Lilac granules (2-4 lobes) ○​ Stains with both acidic and basic dyes ○​ Most common type of WBC ○​ Remains in blood for 10-12 hours then moves to tissues ○​ Phagocytes (engulfs other materials) ○​ Increased in bacterial infection/acute disease ○​ Dead neutrophils accumulates as “pus” at sites of infection ​ Eosinophils ○​ Orange-red granules (2 lobes) ○​ Stains bright red with “eosin”, an acidic stain ○​ Increased in cases of parasitic infection and allergies ○​ Destroys parasites ○​ Reduces inflammation ​ Basophils ○​ Least common  ○​ Contains large cytoplasmic granules that stain blue/purple with basic dyes ○​ Increased in cases of allergies ○​ Releases “histamine” (inflammation), “heparin” (prevents formation of clots) 2.​ Agranulocytes - Very small granules or no specific granules that cannot be easily seen by the light microscope. ​ Lymphocytes ○​ Immune response ○​ Increased in viral infection ○​ Several different types (T cells and B cells) ○​ Leads to production of antibodies ​ Monocytes ○​ Largest size of WBCs ○​ Increased in cases of chronic infection ○​ Produces “macrophages” (Phagocytizes bacteria, dead cells and etc) PLATELETS ​ Minute fragments of cells, consisting of small amount of cytoplasm surrounded by a cell membrane ​ Produced in the red bone marrow from large cells called “megakaryocytes” ○​ Small fragments of these cells break off and enter the blood as “platelets” ​ Plays an important role in preventing blood loss BLOOD LOSS ​ When blood vessels are damaged, blood can leak into other tissues and disrupt normal function ​ Blood that is lost must be replaced by new blood or production of new blood by transfusion HEMOSTASIS - Prevents blood loss by: 1.​ Vascular spasm ​ Temporary constriction of blood vessels (smooth muscle contraction) ​ Stimulated by chemicals (thromboxanes and endothelin) 2.​ Platelet Plug Formation ​ Accumulation of platelets sealing a small break in a blood vessel ​ Maintains the integrity of damaged blood vessels ​ First step - Platelet adhesion (Platelets stick to exposed collagen) ​ Second Step - Platelet release reaction (Activates, change shapes, releases chemical thromboxane and ADP) ​ Third step - Platelet aggregation (Fibrinogen forms bridges) 3.​ Blood Clotting (Coagulation) ​ Blood can be transformed from liquid to gel ○​ Clot - network of thread-like proteins called “fibrin” (traps blood cells and fluid ​ Depends on clotting factors  ​ Clotting Factors: ○​ Proteins in plasma ○​ Only activated following injury ○​ Made in liver ○​ Requires vitamin K Steps in Clot Formation Injury → Clotting factors activated → Prothrombinase (clotting factor) formed and acts upon → Prothrombin → switch to active form Fibrin → Forms a network that traps blood (clots) Clot Formation Control -​ Clots need to be controlled so they don’t spread throughout the body Anticoagulants ​ Prevents clot from forming ​ Heparin and antithrombin (Inactivates thrombin) After site of injury has fully healed, two things happen; ​ Clot Retraction ○​ Condensing/shrinking of clot ○​ Serum in plasma is squeezed out of clot ○​ Helps enhance healing ​ Fibrinolysis ○​ Dissolving of clot ○​ Plasminogen (inactive form) is converted to Plasmin (active form) which will break down clot (fibrin) BLOOD GROUPING * Injury or surgery can lead to blood transfusion, where either transfusion or infusion is called for 1.​ Transfusion - Transfer of blood components from one individual to another 2.​ Infusion - Introduction of fluid other than blood such as saline or glucose solution, into the blood *Early attempts to transfuse blood were often unsuccessful, resulting to; ​ Transfusions reactions ○​ Clumping of blood cells and clotting within blood vessels ○​ Caused by interactions between antigens and antibodies ○​ Antibodies can bind to red blood cell antigens, resulting in agglutination (clumping of cells) or hemolysis (rupture of red blood cells) ​ Antigens - molecules on surface of red blood cells/erythrocytes ○​ Blood groups are determined by antigens on surface of red blood cells ​ Antibodies - proteins in plasma, binds to specific antigens ABO Blood Groups ANTIGENS There are two types of antigen that may appear on the surface of red blood cells; 1.​ Type A antigen - Type A and Type AB blood has these antigen 2.​ Type B antigen - Type B and Type AB blood has these antigen a.​ Type O blood has neither A or B antigen b.​ Type of antigens found on surface of red blood cells are genetically determined ANTIBODIES Antibodies against the antigens are usually present in the plasma of blood 1.​ Type A blood - Has Anti-B antibodies (acts against type B antigens) 2.​ Type B blood - Has Anti-A antibodies (acts against type A antigens) 3.​ Type AB blood - Has neither Anti A or Anti B antibodies 4.​ Type O blood - Has both Anti A and Anti B antibodies Blood donor and recipient according to ABO Blood types ​ Type O are universal donors because they have no antigens ​ Type A can receive blood from A and O blood ​ Type B can receive blood from B and O blood ​ Type AB are universal recipients and can receive from A, B, AB, and O blood ​ Type O can only receive blood from O RH Blood Groups ​ Rh positive means you have Rh antigens ​ 95 - 85% of the population is Rh+ ​ Antibodies only develop if an Rh-person is exposed to Rh+ blood by transfusion or from mother to fetus RH Incompatibility (Hemolytic Disease of Newborn) ​ Destruction of red blood cells in the fetus or newborn, caused by antibodies produced in the Rh-negative mother acting on the Rh-positive blood of the fetus or newborn ​ Occurs when the mother is Rh-negative and the fetus is Rh-positive. Once the fetal blood leaks through the placenta and mixes with the mother’s blood, the mother becomes sensitized to the Rh antigen. The mother produces anti-Rh antibodies that cross the placenta and cause agglutination and hemolysis of fetal red blood cells ​ Mother’s first pregnancy usually there is no problem Prevention of HDN ​ Rh-negative mother is injected with Rho(D) immune globulin (contains antibodies against Rh antigens ○​ Can be given during pregnancy, before and immediately after delivery, misscarriage, or abortion DIAGNOSTIC BLOOD TEST A.​ Blood Typing - Determines ABO and Rh blood groups of a blood sample B.​ Crossmatch - Donor’s blood cells are mixed with recipient's serum, and donor’s serum is mixed with the recipient’s cells  C.​ Complete Blood Count (CBC) - provides information such as RBC count, hemoglobin, hematocrit, and WBC count a.​ Red Blood Cell count i.​ Usually performed with a machine but can be done manually ii.​ Normal values: Male 4.6-6.2 million per ul of blood, Female 4.2-54 million per ul of blood iii.​ Erythrocytosis - overabundance of red blood cells b.​ White blood cell count i.​ Measures total number of white blood cells in blood ii.​ Normal values 5000-9000 WBC/ul of blood iii.​ Leukopenia - lower than normal WBC iv.​ Leukocytosis - Abnormally high WBC c.​ Hemoglobin i.​ Determines amount of hemoglobin in blood ii.​ Indicates anemia (abnormally low hemoglobin measurement) iii.​ 14-18 g/100 ml of blood (Males) iv.​ 12-16 g per 100 ml of blood (Females) d.​ Hematocrit i.​ Percentage of total blood volume composed of RBC ii.​ Males (40-52%) and Females (38-48%) e.​ Differential white blood count i.​ Determines percentage of each 5 kinds of leukocytes 1.​ Neutrophils - 60-70% 2.​ Lymphocytes - 20-25% 3.​ Monocytes - 3-8% 4.​ Eosinophils - 2-4% 5.​ Basophils - 0.5% f.​ Clotting i.​ Can be assessed by the platelet count and the prothrombin time measurement. 1.​ Platelet count - 250,000 - 400,000 platelets/ul 2.​ Thrombocytopenia - Platelet count is greatly reduced, resulting in chronic bleeding through small vessels and capillaries Clotting Disorders and Infectious Diseases of the Blood 1.​ Von willebrand disease a.​ Most common inherited bleeding disorder b.​ Platelet plug formation and the contribution of activated platelets to blood clotting are impaired c.​ Treatments are injection of von willebrand factor or drugs that can increase von willebrand factor levels of blood 2.​ Hemophilia a.​ Genetic disorder where clotting is abnormal or absent b.​ Can result from deficiency or dysfunction of a clotting factor c.​ Most often a sex-linked trait occurs almost exclusively in males 3.​ Septicemia (blood poisoning)  a.​ Spread of microorganisms and their toxins by blood often from medical procedures 4.​ Malaria a.​ Caused by a protozoan introduced into blood by Anopheles mosquito; symptoms include chills and fever produced by toxins released when the protozoan causes red blood cells to rupture 5.​ Infectious mononucleosis a.​ Caused by Epstein-Barr virus, which infects salivary glands and lymphocytes; symptoms include fever, sore throat, and swollen lymph nodes, all probably produced by the immune system response to infected lymphocytes 6.​ Acquired immunodeficiency syndrome (AIDS) a.​ Caused by human immunodeficiency virus (HIV), which infects lymphocytes and suppresses immune system