Blood: An Overview (COOKED 6) - Biology Past Paper

**6.1 Blood: An Overview (COOKED 6)** - The heart pumps 75 ml of blood with each contraction - On average, the heart beats 70 times/minute - 5250 ml per minute - The entire blood supply is circulated each minute **Functions of blood** - Transport - Defense - Regulation **C...

**6.1 Blood: An Overview (COOKED 6)** - The heart pumps 75 ml of blood with each contraction - On average, the heart beats 70 times/minute - 5250 ml per minute - The entire blood supply is circulated each minute **Functions of blood** - Transport - Defense - Regulation **Composition of Blood** - Formed Elements are produced in the red bone marrow - Red blood cells/erythrocytes - White blood cells/leukocytes - Platelets/thrombocytes **Plasma** - Consists of 91% water and 9% salt and organic molecules - Solutes help maintain osmotic pressure of blood - Salt acts as buffers - Solutes: nutrients, waste, hormones - Plasma proteins are the most abundant organic molecules - Most are created by the liver - Create osmotic pressure in the blood **Three major types of plasma proteins** ***Albumins*** - Most abundant of the plasma proteins - Contribute to osmotic pressure more than others - Transport molecules in the blood ***Globulins*** - Some transport substances in the blood - Others, gamma globulins, fight pathogens **6.2 Red Blood Cells and Transport of Gases** **Red Blood Cells (erythrocytes)** - Biconcave shape increases surface area - An unusual cell type in the body due to hemoglobin and unique internal structure - Specialized for oxygen transport **Contains the protein hemoglobin** - A pigment that binds oxygen - The heme portion of Hb binds up to 4 oxygens - Also binds carbon monoxide - When bound to oxygen, hb is called oxyhemoglobin - When oxygen leaves Hb in the tissues, it is called deoxyhemoglobin **Carbon Dioxide Transport** - 7% of co2 is transported dissolved in plasma - 23% binds to the globin portion of hemoglobin - Hemoglobin bound to co2 is called carbaminohemoglobin - 70% is transported in plasma as bicarbonate ion **Red Blood Cells are produced in the Bone Marrow** ***The Production of Red Blood Cells*** - Occurs in the red bone marrow - Lose their nucleus and most organelles ***Erythropoietin*** - Hormone produced by the kidneys when o2 levels of the blood are low - Stimulates the bone marrow to produce more red blood cells **Disorders Involving RBCS** - Jaundice- accumulations of heme in the blood if the liver can't excrete it (skin and whites of the eyes turn yellow (alcohol) - Anemia- too few RBCs or too little hemoglobin - Iron-deficiency anemia- most common form, inadequate intake of dietary iron, so can't make Hb - Pernicious anemia-lack of vitamin b12, which is needed to make RBCS - Folic-acid-deficiency anemia- need folic acid to make RBCS - Hemolytic anemia- too much hemolysis (rupturing the rbcs) - Sickle-cell disease- genetic disease that cause rbcs to become sickle-shaped and prone to rupture (defective hemoglobin structure) **6.3 White Blood Cells and Defense Against Disease** **White blood cells (leukocytes)** - Large cells; nucleus - Translucent unless stained - Less numerous than rbcs - Produced in red bone barrow; production **is regulated by colony stimulating factor** - Fight infection (immune system) - Some live for days some for months/years **Granular Leukocytes** ***Neutrophils*** - Most abundant wbc (50-70%) - Multilobed nucleus - First responders to infection - Engulf pathogens by phagocytosis ***Eosinophils*** - Bilobed nucleus - Many large granules - Function in parasitic infections and play a role in allergies ***Basophils*** - Rarest/blood thinner - Ushaped nucleus - Turns into [mast cells], release histamine during allergic reactions - Histamine dilates blood vessels but constricts breathing passageways **Agranular Leukocytes** ***Lymphocytes*** - 25-35% of wbcs - B and T cells - B cells produce antibodies, which mark a pathogen for destruction - Some cytotoxic t cells directly destroy pathogens ***Monocytes*** - Largest of the wbcs - In tissues, they develop into even larger [macrophages], which engulf pathogens, old cells, and debris **Disorders Involving WBCS** - Severe Combined Immunodeficiency Disease- inherited disease in which lymphocytes don't develop (SCID) (enzyme adeniose deaminase doesn't develop) - Leukemia- group of cancers in which wbcs proliferate without control - Infectious mononucleosis- Epstein Barr virus infects lymphocytes, resulting in fatigue, sore throat, and swollen lymph nodes **6.4 Platelets and Blood Clotting** **Platelets (thrombocytes)** - Result from fragmentation of large cells called megakaryocytes in the red bone marrow - Are not true cells - About 200 billion platelets are made per day - Function in blood clotting (coagulation) - Plasma proteins prothrombin and fibrinogen are also involved in blood clotting - co k is necessary for the formation of prothrombin Blood clotting - Is important so that plasma and formed elements don't leak out of broken vessels - 13 different clotting factors, calcium ions, and enzymes participate in clot formation 1. Blood vessel is punctured 2. Platelets congregate and form a plug 3. Platelets and damaged tissue cells release prothrombin activator, which initiates a cascade of enzymatic reactions 4. Fibrin thread form and trap red blood cells **Disorders related to blood clotting** ***Thrombocytopenia-*** too few platelets; due to not enough being made in the bone marrow or the increased breakdown outside the marrow. Can be caused by leukemia or drugs. Symptoms: excess bleeding. ***Thromboembolism***- when a thrombus (stationary clot) forms, travels (it's then called an embolism), and plugs another vessel. ***Hemophilia A, Hemophilia B*** (Christmas disease), and Von Willebrand disease- genetic deficiencies of a clotting factor. Unable to form clots. Can be partially treated with injections of the missing proteins. **6.5 Human Blood Types** **Blood types** - Determined by proteins on the surface of rbcs **Blood transfusion** - Transfer of blood from one person to another - Need to make sure blood types of compatible to prevent agglutination, or clumping of red blood cells **ABO Blood Groups** ***Antigen*** - Foreign substance, often a glycoprotein, that stimulates an immune response - Blood types are determined by the presence and/or absence of two antigens, type a and type b Type a- rbcs have type a surface antigens, plasma has anti-b antibodies Type B- rbcs have type b surface antigens, plasma has anti-a antibodies Type ab- rbcs have type a and b surface antigens, no antibodies Type o blood- shi got nothing chat ***Blood compatibility*** If antibodies in the recipient's plasma bind to antigens on the surface of donated rbcs, agglutination can occur Crossmatches are to be sure (mix small amounts of blood to test for agglutination O is universal donor because it lacks antigens (only once) ***Rh blood groups*** - Rh is another blood type antigen; if it is present, the blood is rh +, if not its negative - Anti-Rh antibodies only develop after they are exposed to the rh factor Hemolytic disease of the newborn Rh- woman makes baby that is rh+, first time is fine (mixing of fetal and paternal blood, antibodies) Pregnant the second time rh+, antibodies cross placenta and attack the fetus's red blood cells RhoGAM shot prevents this (anti-rh antibodies) **6.6 Homeostasis** The organ systems of the body interact with the cardiovascular system to maintain homeostasis. Interactions include: [The cardiovascular and lymphatic systems] - Interstitial fluid originates from blood plasma, is absorbed by lymphatic capillaries, becoming lymph. - The lymph courses through lymphatic vessels, eventually returning to the cardiovascular system. [The cardiovascular and respiratory systems.] - Delivers oxygen from the lungs to the rest of the body. [The cardiovascular and digestive systems.] - Delivers nutrients from the digestive system to the interstitial fluid. - Removes metabolic waste, delivering waste to excretory organs. [The cardiovascular and muscular systems.] - Contribute to blood movement. - Cardiac muscle contractions circulate blood throughout the body. - Smooth muscle contraction or relaxation in the blood vessel walls changes vessel diameter, helping maintain the correct blood pressure. - Skeletal muscle contraction compresses cardiovascular and lymphatic vessels. - Lymph returns to cardiovascular veins. - Blood in the cardiovascular veins drains back to the heart. [The cardiovascular and skeletal systems.] - Red bone marrow produces blood cells - Bones contribute calcium ions to the process of blood clotting [The cardiovascular and endocrine systems.] - Hormones regulate blood cell production and bone calcium release. [The cardiovascular and urinary systems.] - The kidneys help regulate the acid-base and water-salt balances of the blood and interstitial fluid. - Erythropoietin, a hormone produced by the kidneys, stimulates red blood cell production. Quiz extras: coagulation contributes to homeostasis by keeping blood in the vessels A person who cannot produce the enzyme adenosine deaminase may develop: