Blood Compatibility Mode PDF

Chapter 7  The Functions of Blood Transportation: various substances transported throughout the body. Homeostasis: body temperature (heat in blood is transported near our skin’s surface when we are hot), pH of body fluids (blood contains a buffering system, including ion buffers and h...

Chapter 7  The Functions of Blood Transportation: various substances transported throughout the body. Homeostasis: body temperature (heat in blood is transported near our skin’s surface when we are hot), pH of body fluids (blood contains a buffering system, including ion buffers and hemoglobin that bind to excess hydrogen ions.) Defense: various white blood cells and antibodies against infection Clotting: platelets and fibrinogen proteins prevent excessive loss of blood Components of blood Cellular portion (45% of volume) Red blood cells: transport oxygen and some carbon dioxide. White blood cells: defend against viral, bacterial, protist, animal invaders as well as virus-infected cells and cancerous cells Platelets: critical for blood clotting Source of all: stem cells of red bone marrow Components of blood Plasma (55% of volume) Water: primary constituent (90%), biological solvent Ions: pH buffers, for cell function and volume, needed for excitable cells like muscles and nerves Hormones: messages released by endocrine glands into the blood Gases: oxygen (a little) and carbon dioxide (most) dissolved in plasma Nutrients: such as amino acids, glucose and lipids. Lipids are often bound to special globulin transport proteins, since they do not dissolve in blood plasma Wastes: ammonia, urea and uric acid, removed from blood at kidneys Components of blood Examples of plasma proteins, dissolved in blood plasma: Albumins: produced by liver, maintain osmotic balance between blood and extracellular fluid (maintains fluid volume of blood). Antibodies: produced by white blood cells, bind to foreign substances (like bacteria / viruses), Fibrinogen: produced by liver, convert to fibrin network for blood clotting  Red blood cells Structure: no nucleus, no organelles, flattened disks (allows flexibility). Limited life span: only 120 days on average. Old cells broken into components in liver and spleen: iron recycled to red bone marrow, amino acids used, heme groups becomes part of bile. Control of red blood cell production: erythropoietin hormone Homeostasis of oxygen carrying capacity Oxygen decrease detected by cells of kidneys, which secretes erythropoietin to increase red blood cell production by stem cells in the red bone marrow. Increased oxygen levels result in reduced erythropoietin secretion. Why train at high altitude?  Hemoglobin Each red blood cell with 300 million hemoglobin molecules that carry 1.2 billion oxygen molecules! Four polypeptide chains, two types: alpha and beta, each with 1 heme group that includes iron (Fe) to bind oxygen. Each hemoglobin molecule binds 4 oxygen molecules.  Hemoglobin and oxygen binding Hemoglobin binds to oxygen: higher pH (less acid), high blood oxygen concentration, lower temperature (like in lungs) Hemoglobin releases oxygen: lower pH (more acidic), low blood oxygen concentration, higher temperatures (like in active tissues, like exercising muscles) CO2 + H2O H2CO3 H+ + HCO3- Carbon dioxide + Water Carbonic acid Hydrogen ion + Bicarbonate ion  Stopping loss of blood Stages: 1) Vascular spasm: smooth muscle constricts blood vessels to reduce, or completely stop blood flow 2) Platelet plug formation: seal the ruptured blood vessel. Collagen proteins in damaged blood vessel à change in platelets: get stickier, bigger and “spiky” to stick together. Platelets contract, to bring wound together. 3) Coagulation: formation of a blood clot. Chemical signals from cells and platelets converts soluble fibrinogen into insoluble fibrin, forms a clot with trapped red blood cells and platelets. Stopping loss of blood Slide 7.6 What can you do to help stop the bleeding if someone is badly cut (first aid)? What can you do to help stop the bleeding if someone is badly cut? First aid for severe bleeding: Apply constant direct pressure Raise the arm or leg above the heart Put pressure on the artery supplying the arm or leg, to reduce blood loss Blood types and antibodies Antigens: proteins/glycoproteins in cell membranes B lymphocytes produce protein antibodies. Antibodies bind to foreign antigens Wrong blood type results in agglutination: clumps of wrong red blood cells and antibodies can get stuck in small blood vessels, damaging organs due to lack of blood supply, and possibly leading to death. Blood types and antibodies  RhRhfactor factor Rh antigen: Rh positive means you have the Rh antigen or negative means you don’t have it. Rh negative people can receive Rh positive blood once, but Rh antibodies are produced that will cause agglutination the 2nd time they receive Rh positive blood. A-like and B-like antigens occur naturally, so humans usually have the antibodies already. Rh like antigens do not occur naturally, so a first exposure is needed to produce antibodies. Blood type survey. Figuring out who can donate to whom. Steps: 1) Draw recipient’s antigens 2) Draw recipient’s antibodies they can create 3) If there is a match between donor’s antigens and recipient’s antibodies = agglutination! Don’t give that blood!  RhRhfactor factorand pregnancy Rh negative women pregnant with 1st Rh positive baby: baby is fine, but anti Rh antibodies are formed in the mother. Rh negative women pregnant with 2nd Rh positive baby: antbodies cross placenta and child’s blood will be destroyed possibly resulting in hemolytic disease of the newborn (baby with severe anemia, jaundice, possible death). Treat with RhoGam prior to first birth, so baby’s blood is destroyed before it triggers an immune response.  Blood disorders: carbon monoxide poisoning Carbon monoxide competes with oxygen It is produced by burning fuel (motor exhaust), burning wood, charcoal and tobacco. CO binds with hemoglobin, and stays bound for a long time. Oxygen cannot bind under these circumstances. Motor exhaust and fires should never be in a closed room, you will feel faint, pass out and die without fresh air.  Blood disorders: anemia Reduction in oxygen-carrying capacity à weakness, fatigue Iron deficiency: low iron = not enough heme groups formed Aplastic: bone marrow does not produce enough red blood cells Hemmorhagic: extreme blood loss (from injuries, malaria that bursts red blood cells) Sickle cell: red blood cell sickle shaped, destroyed early by body (genetic) Thalassemia: insufficient alpha or beta protein chains of hemoglobin produced à decreased oxygen carrying capacity. Blood transfusions may be necessary à treatment to remove excess iron from transfusions (genetic). Blood disorders: leukemia Cancer of white blood cells, white blood cell division becomes uncontrolled. Abnormal white blood cells crowd out normal white and red blood cell production, and huge numbers of white blood cells interfere with normal organ function. Aplastic anemia results, wounds are slow to clot (inadequate platelets), white blood cells may not work. Eventual death by internal bleeding or infection. Blood disorders: hemophilia Hemophilia leads to uncontrolled bleeding Potentially due to: Insufficient platelets (leukemia) Liver diseases, as clotting proteins are not produced Vitamin K deficiency Inheritence, as defective or no clotting proteins are produced  Chiras, DD Human Biology Health, Homeostasis, and the Environment,Jones and Bartlett, Sudbury, Mass, 2002