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

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

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

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

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

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

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

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 online.com/ViewObject.aspx?ID=AP online.com/ViewObject.aspx?ID=AP14604

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

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

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

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