2. Functions: Reduces distance for diffusion of materials Internal Transport: O 2 & CO 2 Nutrients Hormones

3. Types of Circulatory Systems None Porifera, Cindarians, Ctenophores, Platyhelminthes & Nematodes GV cavity Flat body Fluid in pseudocoelom

4. Types, cont. Open circulatory system Mollusks & Arthropods Heart, blood vessels, hemocoel, hemolymph Circulation: gills  atria  ventricle  vessels  hemocoel  vessels  gills In insects, hemolymph distributes nutrients & hormones; gas diffuses into tracheae

5. Types, cont. Closed circulatory system More efficient Blood vessels are continuous Capillaries permit diffusion Focus on Vertebrates

6. Vertebrate Circulatory System Transport of nutrients & oxygen, metabolic wastes & hormones Fluid balance Distribution of heat pH Defense

7. 5 L – 5.5 L in humans 55% is plasma 45% blood cells & platelets

8. Plasma Water, proteins, salts, other materials Plasma proteins: Fibrinogen Globulins: α, β, Γ Albumins Proteins maintain blood volume & act as buffers

9. Erythrocytes (RBCs) Transport oxygen Contains hemoglobin Mammalian RBCs lack nuclei Disc-shaped Formed in red bone marrow - erythropoietin Humans – 30 trillion RBCs Life span of 120 days http://www.wisc- online.com/ViewObject.aspx?ID=AP14604 http://www.wisc- online.com/ViewObject.aspx?ID=AP14604

10. Other Blood Cells Leukocytes (WBCs) Immunity Platelets Blood clotting Stimulate immune system??

11. Blood Clotting Blood Vessels constricts Platelets stick to cut, signal for more platelets Clotting factor activated by contact with injured tissue

12. Prothrombin converted to thrombin Thrombin converts fibrinogen to fibrin Fibrin forms threads over opening, traps blood cells and platelets

14. Blood Diseases & Disorders Anemia Hemoglobin deficiency Leukemia Cancer involving WBCs Hemophilia Absence of clotting factor