Human Biology: Circulatory System

1. Human Biology: Circulatory System Lesson 2: Blood and the Lymphatic System (Inquiry into Life pg. 226-230, 240-251)

2. Today’s Objectives • Describe the components of blood, including: • Describe the shape, function, and origin of red blood cells, white blood cells, and platelets • List the major components of plasma • Explain the roles of antigens and antibodies • Describe the inter-relationships of the structures of the lymphatic system, including: • Describe the functions of the lymphatic system • Identify and give functions of lymph capillaries, veins, and nodes

4. Components of Blood • A) Plasma: 55% of blood • B) Formed Elements: 45% of blood • Erythrocytes (Red Blood Cells) • Leukocytes (White Blood Cells) • Thrombocytes (Platelets)

6. Constituents of Plasma • NAMEFUNCTION • A. Water (90%) Blood Volume • Transport of cells and materials • B. Plasma Proteins Helps maintain Osmotic pressure in blood. • a) Albumen -Transports • b) Fibrinogen -Blood Clotting • c) Globulins -Infection fighting • C. Gases • a) Oxygen -For respiration • b) Carbon Dioxide -Waste • D. Nutrients Energy source - Raw materials for the • a) A.A. Glucose, body • Fatty acids, Glycerol • E. Salts Osmotic Pressure • Helps in Metabolism • F. Wastes Waste production of Cellular Reactions.

7. Shape, Function, and Origin of RBC • Red Blood Cells (Erythrocytes)Video • Live about 120 days • Produced in Red Bone Marrow (in skull, ribs, vertebrae, and long bones) • Myeloid stem cells form RBC • These stem cells are called Erythroblasts, which will differentiate into Erythrocytes • Produce about 5 million/second • RBC contain a protein called hemoglobin • Old RBC destroyed in the liver and spleen

8. Hemoglobin • Hemoglobin contains iron (gives its red color) • Picks up oxygen in the lungs then releases is it in the tissues • Approximately 200,000,000 hemoglobin molecules in one RBC • If hemoglobin was not packaged in RBC, oxygen would leak out of the circulatory system

9. Shape, Function, and Origin of WBC • White Blood Cells (Leukocytes)Video • Larger than RBC • Have a nucleus (RBC do not) • Less numerous than RBC (700:1) • Do not have a definite shape • Function: • Fights against infection in two ways: • Phagocytosis • Produce Antibodies

10. Types of White Blood Cells • Granular Leukocytes (Granulocytes) • Have grains, or granules in their cytoplasm which are filled with enzymes and proteins to fight against microbes • Formed in the bone marrow • 60-70% of Leukocytes • Example: Neutrophil – phagocytize and digest bacteria • Agranular Leukocytes (Agranulocytes) • No granules in cytoplasm • Produced by lymphatic tissue • 25-30% of Leukocytes • Example: Monocytes (phagocytize pathogens and cellular debris) and Lymphocytes (responsible for specific immunity)

11. Agranulocytes • Monocytes: • Largest WBC • Take up residence in tissues • Differentiate into larger ``macrophages`` which phagocytize microbes and stimulate other WBC • Lymphocytes: • B-Lymphocytes – produced in bone and lymphoid tissue • T-Lymphocytes – produced in the thymus and give rise to plasma cells

13. Platelets (Thrombocytes) • 2 billion produced/day • Broken fragments of larger cells • Very important in blood clotting • Blood Clotting: • Need three things in blood: • - Platelets • - Prothrombin • - Fibrinogen • 1) Platelets clump at the site of the “leak” and partially close it • 2) Platelets and the injured tissue together release an enzyme called Thromboplastin

14. Blood Clotting • 3) Thromboplastin converts a blood protein (Prothrombin) into a new substance called Thrombin • 4) Thrombin acts as an enzyme that breaks the ends off another blood protein called Fibrinogen • 5) Fibrinogen is then converted into Fibrin • 6) Fibrin has sticky ends and forms a lattice or network over the leak where blood cells get trapped, forming a clot • 7) Fibrin clot is only temporary – as soon as the blood vessel repair is initiated, and enzyme called Plasmin destroys the network

16. RBC trapped in the FIBRIN network

17. Lymphatic System (see video) • Functions: • 1) Takes excess tissue fluid and sends it to the circulatory system (lymphatic system joins the circulatory system at the subclavian veins) • 2) Products of fat digestion are absorbed into Lacteals which lead to the Lymph vessels and Nodes • 3) Lymph nodes produce Lymphocytes (a type of WBC) and help the body defend against disease • 4) Lymph nodes act as filters and trap bacteria and other debris (helps to purify the body fluids)

18. Lymphatic Structures • Spleen: • Largest Lymphatic Tissue • Produces lymphocytes and stores excess blood • If your blood pressure is high, stores blood so blood pressure lowers • If your blood pressure is low, it contracts and squeezes out blood, sending it back to the system so that blood pressure rises • Thymus Gland: • Bi-lobed structure which is important In the maturing of lymphocytes • Gets smaller as you age

19. Lymphatic Structures • Tonsils and Appendix: • Contain lymphoid tissue • Thought to help remove invading organisms and viruses • Lymphatic Tissue: • Produce lymphocytes and stores excess blood • Lymph Vessels: • Similar to veins, but fluid only travels in one direction (lymph veins and capillaries, but no lymph arteries) • Lymph Nodes: • Small oval or round tissues which filter fluids and produce lymphocytes • Lacteals: • Sacs in villi of digestive system which absorb products of fat digestion

20. Infection Fighting – Inflammatory Response • Foreign Substances (bacteria or viruses) attack • Monocytes and Neutrophils engulf the bacteria or viruses in amoeboid fashion (phagocytosis) • These WBC are able to travel to the site of the infection through capillary network • Dead tissue, cells, bacteria, dead and living neutrophils all together make up Pus

21. Lymphocytes • Produce antibodies • One antibody fights a specific antigen (foreign protein) • Antigen + Antibody inactive complex • Antigens: • A protein found in the outer membrane of RBCs • Stimulate an immune response (production of antibodies) • The type of protein determines the blood type • Can also be a foreign protein introduced to the body • Antibodies: • A protein found in the plasma • Attack unwanted proteins (bacteria or viruses) • End result is agglutination

23. ABO Blood System(see video)

26. Rhesus Factor • Red blood cells may have another antigen called antigen D, known as the Rhesus Factor. • This distinguishes blood as being RH+ or RH-. • Therefore there are 8 possible blood types.