Chapter 11 Blood Lecture Outline • • • • Blood function & composition Red blood cells Blood types Blood clotting Blood is a mixture of cells and plasma Human Blood after centrifugation • ~55% Plasma • ~45% Red blood cells • <1% White blood cells and platelets (“buffy coat”) Blood plasma • Water • Nutrients • Solutes- Na+, Cl-, wastes, CO2, etc. • Contains humoral immune elements • Some innate immunity All blood cells are part of the hematopoetic stem cell lineage Hematopoetic stem cells differentiate into all blood cells • Pluripotent- able to become any one of many cell types • Includes T cells, B cells, macrophages, etc. Red blood cells carry oxygen and CO2 • Lose nucleus in development • Short-lived, no repair • Packed solid with hemoglobin • Membranes designed to maximize surface area • Facilitate gas transfer Hemoglobin • The oxygen-carrying protein • Heterotetrameric protein • 2 alpha subunits, 2 beta • Each subunit holds a Heme group • Each heme holds an Fe++ ion • Each Fe++ can bind an O2 Hemoglobin binding curve • In areas of High O2 (e.g., lungs)- binds O2 very well (picks up O2) • In areas of Low O2 (e.g., muscles) binds O2 poorly (drops off O2) • Myoglobin binds O2 in muscle & organ tissues Cystic Fibrosis and Sickle Cell Anemia exhibit Mendelian Inheritance • Both are recessive disorders • Both exhibit multiple phenotypic traits for a single gene defect (pleiotropy) Sickle cell anemia • Genetic inheritance • A point mutation in DNA • Causes malformation of hemoglobin • Oxygen transport inhibited • Pleiotropic Platelets assist with blood clotting • Recruit plasma protein fibrinogen to a cut • They release clotting factors • Clotting factors convert fibrinogen to fibrin • Fibrin net prevents blood loss The liquid part of blood is called 1. 2. 3. 4. 5. A) water. B) plasma. C) serum. D) extrastitial fluid. E) anionic fluid. The Immune system is the body’s defense system • Against: – – – – – – – Bacteria Viruses Protists Other living invaders Toxins Foreign debris Cancerous cells • The immune system is complex • Defends against threats known and unknown White blood cells come in a great variety of types Phagocytic white blood cells devour bacteria Blood • Blood functions in transportation, protection, and regulation • Blood consists of plasma and formed elements • Blood types are determined by antigens on the surface of red blood cells • Blood clotting occurs in a regulated sequence of events Composition of Blood Figure 11.1 Composition of Blood Table 11.1 (1 of 3) Composition of Blood Table 11.1 (2 of 3) Composition of Blood Table 11.1 (3 of 3) Plasma and Formed Elements • Plasma – Makes up about 55% of blood – About 93% water – Remaining 7% consists of dissolved substances including nutrients • Ions, dissolved gases, hormones, plasma proteins, and waste products Plasma and Formed Elements • Plasma proteins include – Albumins • Needed for the water-balancing properties of plasma – Globulins • Transport lipids and fat-soluble vitamins • Some are antibodies – Clotting proteins • I.e., fibrinogen Plasma and Formed Elements • Stem cells give rise to the formed elements – Platelets – White blood cells – Red blood cells • All transported by the plasma Formed Elements Figure 11.2 Plasma and Formed Elements • Platelets – Sometimes called thrombocytes – Fragments of larger precursor cells called megakaryocytes – Essential to blood clotting Plasma and Formed Elements Table 11.1 (1 of 3) White Blood Cells • White blood cells (WBCs) – Also called or leukocytes – Help defend the body against disease – Remove wastes, toxins, and damaged and abnormal cells White Blood Cells Table 11.1 (2 of 3) White Blood Cells • Nucleated cells that are produced in the red bone marrow • One type, the lymphocyte, can be produced in the lymph nodes and in other lymphoid tissue White Blood Cells • WBCs have the unique ability to move to the site of infection, inflammation, or tissue damage • Some WBCs are capable of phagocytosis White Blood Cells Figure 11.3 Red blood cell • Often little contrast under LM • >99% of visible cells under the microscope Platelets • For blood clotting White Blood cells come in a wide variety of types • • • • • • Neutrophils Lymphocytes Monocytes Eosinophils Basophils Macrophages WBC’s can be categorized according to a few criteria • Function: – Innate immunity vs. – Adaptive immunity • Frequency: 1. 2. 3. 4. 5. Neutrophils Lymphocytes Monocytes Eosinophils Basophils • Cell structures: – Granulocytes – Agranulocytes Granulocytes • Contain Granules • For innate immunity • Granules contain cellular weaponry and signals • 3 major types: – Eosinophils – Basophils – Neutrophils Neutrophils • “Neutral-loving” • Most common granulocyte • Lobed nucleus Eosinophils • “Acid loving”- bind to acidic stain (red) Basophils • “Base-loving”- bind to basic stain (blue) • Involved in allergic reactions Agranulocytes • Lymphocytes • Monocytes Monocytes • Can respond quickly to infection • Can differentiate into: – Macrophages – Dendritic cells Lymphocytes • No granules • Smaller cell, larger nucelus • Three major types of lymphocyte: • T cells- 65% • B cells-25% – Adaptive immunity • Natural killer (NK) cells 10% – Innate immunity White Blood Cells • Five types of white blood cells • Two groups based on the presence or absence of granules in their cytoplasm – Granulocytes – Agranulocytes White Blood Cells: Granulocytes • Granulocytes are classified on their staining ability – Neutrophils do not stain – Basophils stain purple with a basic stain – Eosinophils stain pink with the stain eosin White Blood Cells: Granulocytes Table 11.1 (2 of 3) White Blood Cells: Granulocytes • Neutrophils – The most abundant of the WBCs – Engulf microbes by phagocytosis, thus curbing the spread of infection • Pus – Dead neutrophils, along with bacteria and cellular debris – Associated with infection White Blood Cells: Granulocytes • Eosinophils – Defend against parasitic worms – Lessen the severity of allergies White Blood Cells: Granulocytes • Basophils – Release histamine • A chemical that attracts other white blood cells • Causes the blood vessels to dilate – Also play a role in some allergic reactions White Blood Cells: Agranulocytes • Agranulocytes – Lack granules – Monocytes – Lymphocytes White Blood Cells: Agranulocytes Table 11.1 (3 of 3) White Blood Cells: Agranulocytes • Monocytes – The largest of the formed elements – Develop into macrophages • Phagocytic cells that engulf invading microbes, dead cells, and cellular debris White Blood Cells: Agranulocytes • B lymphocytes – Give rise to plasma cells, which produce antibodies • Proteins that recognize specific molecules called antigens on the surface of invading microbes or other foreign cells White Blood Cells: Agranulocytes • T lymphocytes – Specialized white blood cells – Kill cells not recognized as coming from the body, or cells that are cancerous Red Blood Cells • Red blood cells (RBCs) – Also called erythrocytes – Transport oxygen to the cells – Carry about 23% of the total carbon dioxide – Shaped like biconcave disks and are very flexible – No nucleus Red Blood Cells Figure 11.4 Red Blood Cells • Hemoglobin – Molecules in the RBCs – Bind to oxygen, making oxyhemoglobin • Needed for aerobic respiration • Hemoglobin has a much greater affinity for carbon monoxide – Odorless and tasteless – An insidious poison Structure of Hemoglobin Each hemoglobin molecule consists of four polypeptide chains (globins). Each polypeptide chain contains a heme group with an iron atom that binds to oxygen. Oxygen molecules bind to hemoglobin Oxygen molecules released Each hemoglobin molecule can carry up to four molecules of oxygen. Figure 11.5 Red Blood Cells • Produced in the red bone marrow • Live about 120 days • When cells in the kidney detect a decrease in oxygen they release erythropoeitin – A hormone that can speed RBC production • Undergo phagocytosis in the liver and spleen – The heme in hemoglobin is salvaged and sent to the bone marrow for recycling – Remainder is degraded to bilirublin Red Blood Cells Figure 11.6 Red Blood Cells PLAY Animation—Blood Red Blood Cell Disorders • Anemia – Several types – The blood’s ability to carry oxygen is reduced – Can result from too little hemoglobin, too few red blood cells, or both • Symptoms – Fatigue, headaches, dizziness, paleness, breathlessness, and heart palpitations Red Blood Cell Disorders • Iron deficiency anemia – Most common – Leads to inadequate hemoglobin production • Causes – A diet that contains too little iron – An inability to absorb iron from the digestive system – Blood loss Red Blood Cell Disorders • Hemolytic anemias – Occur when red blood cell destruction exceeds production • Causes – Infections – Defects in the membranes of RBCs – Transfusion of mismatched blood – Hemoglobin abnormalities Red Blood Cells • Sickle-cell anemia – An example of a hemolytic anemia – Caused by genetically abnormal hemoglobin • RBCs form a sickle shape when the blood’s oxygen content is low – Results in RBCs that are fragile and rupture easily, clogging small blood vessels and promoting clot formation Red Blood Cell Disorders • Pernicious anemia – Occurs when there is insufficient production of red blood cells • Lack of vitamin B12 due to the lack of intrinsic factor secretion from the stomach lining White Blood Cell Disorders • Infectious mononucleosis – Viral disease of the lymphocytes caused by the Epstein–Barr virus White Blood Cell Disorders • Leukemia – A cancer of the WBCs that causes the number of WBCs to increase – These cells do not function as normal WBCs Blood Types • Genetically determined by the glycoproteins found on the surface of RBCs • Named by the antigen found on the surface of the cell –A –B – AB –O Blood Types Table 11.2 Blood Types Figure 11.7a Blood Types Figure 11.7b–c Blood Types • Agglutination, or clumping – Occurs when someone’s antibodies contact a foreign cell Blood Types • Rh factor – Another important antigen – Becomes critical during pregnancies of Rhnegative women • Individuals who have Rh antigens on their RBCs are Rh-negative Blood Types • Rh-negative person will not form anti-Rh antibodies unless he or she has been exposed to the Rh antigen – Transfusion – Having given birth to a Rh-positive baby Rh Factor Figure 11.8 (1 of 4) Rh Factor Figure 11.8 (2 of 4) Rh Factor Figure 11.8 (3 of 4) Rh Factor Figure 11.8 (4 of 4) Blood Types • Hemolytic disease of the newborn – Anti-Rh antibodies can develop in the mother – They can cross the placenta, destroying the Rhpositive fetus’s RBCs – The baby may die or be very anemic • Rhogam – A serum containing antibodies against the Rh antigens – Given to Rh- mothers to prevent the production of anti-Rh antibodies Blood Types PLAY Animation—Blood Types Blood Clotting Occurs in a Regulated Sequence of Events • The clotting process begins when, upon injury, a blood vessel spasms to reduce blood flow Blood Clotting Occurs in a Regulated Sequence of Events Figure 11.9 Blood Clotting • Collagen fibers then form in the wound that snag platelets • When platelets contact collagen fibers, they swell, form extensions, and stick together to form a platelet plug Blood Clotting • Next, prothrombin activator converts prothrombin to thrombin – Causes fibrinogen to form long strands of fibrin – Fibrin strands form a web that traps blood cells and forms a clot Blood Clotting • When the wound is healed – Plasmin, formed from plasminogen, digests the fibrin strands of the clot • If even one of the clotting factors is lacking, the process can be slowed or completely blocked • Vitamin K is needed to synthesize prothrombin in the liver – Clotting does not occur without it Hemophilia • Hemophilia – Inherited condition – Prevents one or more of the clotting factors from being made – The affected individual bleeds excessively and needs to have the clotting factors restored Blood Clotting • Formation of unnecessary blood clots can have immediate health consequences – Clots can disrupt blood flow – A clot that continues to circulate is called an embolus – When it lodges in a vessel it is called a thrombus • Can cause a heart attack or stroke