Circulation Deliver O2 and food remove metabolic waste complexity varies in different groups or organisms limits organismal size Quiz Hemostasis maintains blood volume Quiz Blood flow is slowest at what point in the circulatory system capillaries Homeostasis circulatory system maintains volume composition and temp of extracellular fluids also tied to lymphatic system Respiratory pigments o Hemoglobin iron what binds to oxygen vertebrates in cells o Hemocyanin copper molluscs arthropods dissolved in blood dissolved in blood is helpful in areas of higher pressure b c the temperature is cooler and blood flows slower and being dissolved in blood allows for the Hemocyanin to bind to more oxygen and fit more of these molecules in blood since they take up less space o Hemerythrin iron sipuncilids priapulids brachiopods in cells Myohemirythrin found in marine invertebrate muscle cells o Chlorocruorin iron annelids dissolved in blood Marine organisms with gastrovascular cavities have no specialized circulatory system o Cnidarians jellyfish corals sea anemones hydrozoans o Flatworms integumentary exchange tapeworms leeches Circulatory systems o Open system heart contracts and blood pumped to spaces or cavities in body tissues hemocyl from the ostea and heart after heart relaxes it causes a negative pressure gradient so the blood is pushed back through the hemocyl to the heart again very slow o Arthropods Blood hemolymph interstitial fluid Blood flow by heart pump and muscle contraction No blood pressure in hemocoel so blood flows slowly Pigment in hemocyanin Movement of tail can help create pressure gradients so blood flows o Decapod crustacean circulatory system a case that is neither open nor closed more closed than open Blood pools in sinuses and then drains back into heart but they have arteries veins and capillaries o Why don t crabs bleed to death when they lose a limb Blood contains amebocytes for phagocytosis and clotting Explosive cells disintegrate releasing substance that converts fibrinogen to fibrin causing clotting thickening of blood Very fast o Platelets Membrane bound cell fragments Derived from megakaryocytes which arise from stem cells Release substance that initiate blood clotting Horseshoe crab blood protects public health o Endotoxin main bacterial toxin o Primitive immune system causes blood clotting in response to bacteria o Is used by pharmaceutical companies to test for Rx to medications Indicates presence of bacteria o Blood in crab surrounds toxin and begins clotting if this happens that means there s an endotoxin in the medication and it cannot be used Open circulatory system molluscs bivalves and snails o Advantages less susceptible to pressure greater control over body temperature o Disadvantages less control over oxygen delivery less efficient filtration of blood and lymph The exception to the rule cephalopods have closed circulatory system o Systemic heart and two branchial hearts o Blood pumped through both the systemic tissues and through gills Similar to mammals o Advantage not relying on a single pump through one heart to pump blood you have three hearts to pump through separately swim very fast need more oxygen increase speed of pumping more oxygen Closed circulatory system of annelids o Feather duster worms o 5 hearts encircle esophagus o Dorsal vessel posterior flow o Ventral vessel anterior flow o Oxygen exchange in Parapodia main area of gas diffusion deliver oxygen remove CO2 o Same process just added two more hearts Quiz what is the evolutionary link between the following aspects of marine organismal biology body size gas exchange the gradient in circulatory systems from none to open to closed systems o If body size is small you can diffuse across the surface for gas exchange large body size means you have to have a really good defined circulatory system in order to move things throughout the body Comparison of circulatory systems in fish Standard fish plan heart to gills to systemic tissues closed plan of ordinary fish o 2 problems heart must push blood through entire circuit heart is oxygenated using spent containing CO2 instead of oxygen blood o Variations Standard fish have gills and systemic tissues in series Others have gills and systemic tissues in parallel O2 picked up in mouth gut or swim bladder Originally considered poor adaptation inefficient mixing Now considered potential adaption to provide oxygen to the heart ALL VERTEBRATES HAVE CLOSED CIRCULATORY SYSTEM Reptiles are intermediate o Some have partial separation of ventricles o Others have complete separation as we saw in mammals o Some mixing of blood only getting half of O2 you need Circulatory systems in marine reptiles o Temperature main problem for diving reptiles Cold water strips heat from organism Max dive 5 hours Mammal circulatory system blood vessels heart Functions of mammal blood o Transports oxygen and nutrients to the cell o Carries CO2 and wastes away from cells o Helps stabilize internal pH o Carries infection fighting cells o Helps equalize temperature hemostasis and homeostasis in one system Components of mammal blood o Plasma portion liquid water proteins ions o Cellular portion white blood red blood cells platelets Erythrocytes red cells o Most numerous cells in blood o Transport oxygen and CO2 o Colored red in mammals by oxygen binding pigment hemoglobin o Form from stem cells in bone marrow o Have no nucleus when mature o Continually replaced 120 days Transition from artery to veins o Heart to arteries to arterioles to capillaries to venules to veins to heart o At the capillaries Blood flow slows down because of large ross sectional area Diffusion zones between blood and interstitial fluid Large total area so pressure very low Movement across wall by diffusion Need it to slow down b c you need to exchange CO2 and O2 for gas diffusion Diving Physiology of marine mammals Duration of dives in diving mammals o Can be very long o Most relatively short o Can be very deep o Most relatively shallow Respiratory diving adaptations of whales to minimize the bends o Lungs and rib cage modified for collapse b c lack sternum so are free floating anteriorly no rigidity can compress these at 25 100 m depending on species o Remaining air squeezed out of alveoli and into trachea and bronchi no remaining air at the end to cause them to get the bends o We can t collapse our rib cage because we have a sternum very rigid system Alveoli air sacs how O2 and CO2 transports are