Functions:Reduces distance for diffusion of materials

Internal Transport:

O2 & CO2

Nutrients

Hormones

Types of Circulatory SystemsNone

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 SystemTransport of nutrients & oxygen, metabolic

wastes & hormones

Fluid balance

Distribution of heat

pH

Defense

5 L – 5.5 L in humans55% is plasma

45% blood cells & platelets

PlasmaWater, proteins, salts, other materials

Plasma proteins:FibrinogenGlobulins: α, β, ΓAlbumins

Proteins maintain blood volume & act as buffers

Erythrocytes (RBCs)Transport oxygen

Contains hemoglobin

Mammalian RBCs lack nucleiDisc-shapedFormed in red bone marrow - erythropoietinHumans – 30 trillion RBCsLife span of 120 days

http://www.wisc-online.com/ViewObject.aspx?ID=AP14604

Other Blood CellsLeukocytes (WBCs)

Immunity

PlateletsBlood clottingStimulate immune system??

Blood ClottingBlood 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 & DisordersAnemia

Hemoglobin deficiency

LeukemiaCancer involving WBCs

HemophiliaAbsence of clotting factor