Section Outline 37–2 Blood and the Lymphatic System A. Blood Plasma B. Blood Cells 1. Red Blood Cells 2. White Blood Cells 3. Platelets and Blood Clotting C. The Lymphatic System

37–2. Blood and the Lymphatic System A 37–2 Blood and the Lymphatic System A. Blood Plasma Human body contain 4-6 liters of blood 45% of blood is red blood cells and the other 55% is plasma - a straw colored fluid Plasma – 90% water and 10% dissolved gases, salts, nutrients, enzymes, hormones, waste products, and proteins called plasma proteins. Plasma proteins – transport substances, and contain Fibroinogen, which helps blood to clot when you get a scratch  

B. Blood Cells 1. Red Blood Cells a. k. a B. Blood Cells 1. Red Blood Cells a.k.a. erythrocytes Red blood cells transport oxygen Hemoglobin – iron-containing protein that binds to oxygen in the lungs and transports it to tissues through out the body

2. White Blood Cells -a.k.a. leukocytes -DO NOT contain hemoglobin -Made also in Red bone marrow -White blood cells are the “army” of the circulatory system – they guard against infection, fight parasites, and attack bacteria  

Lymphocytes – a special class of white blood cells, produce antibodies that are proteins that help destroy pathogens. White blood cells have the ability to slip out of capillary walls travel through the lymphatic system and attack an invading organism. Ex. Virus

3. Platelets and Blood Clotting Blood clotting is made possible by plasma proteins and cell fragments called platelets. Platelets – cell fragment that cluster together at an opening in a blood vessle. The platelets release clotting factor proteins and clot the hole     

Figure 37-10 Blood Clotting Section 37-2 Break in Capillary Wall Blood vessels injured. Clumping of Platelets Platelets clump at the site and release thromboplastin. Thromboplastin converts prothrombin into thrombin.. Clot Forms Thrombin converts fibrinogen into fibrin, which causes a clot. The clot prevents further loss of blood..

4. Blood clotting disorder 4. Blood clotting disorder *Hemophilia is a genetic disorder that results from a defective protein in the clotting pathway *People with this disorder cannot produce blood clots that are firm enough to stop even minor bleeding *This can be treated with injections of the protein

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