Gas Exchange in Vertebrate Marine Organisms Quiz Marine invertebrates commonly respire across their entire body wall gills tentacles entire body wall or all of the above Quiz Which invertebrates discussed last time had invaginations or outpocketings as respiratory structures Echinoderms polychaete annelids and urechis caupo all of the above Different approaches o CO2 and O2 can only cross cell membranes when they are dissolved in water o Larger organisms body wall no longer sufficient for gas diffusion Quiz fish use what physiological adaptation to enhance the efficiency of gas exchange in the gills increased body temp counter current exchange slowing of the heart rate none of the above counter current exchange Gills o Greatly increase surface area Found in variety of organisms Essentially are blood vessels covered by thin epithelium Series of plates Gill filaments highly vascularized Unidirectional water flow o Counter currently exchange blood and water are flowing opposite one another increases efficiency in uptake of oxygen and release of carbon dioxide Counter current exchange o Diagram gas will naturally diffuse from water to blood b c it will always go down the concentration gradient o What is counter current exchange how does it occur why is it important what would happen if blood and water flowed in same direction They would equilibrate and the blood would stop flowing and possibly only have half of the amount of oxygen concentration that it needed Do sharks really have to swim to breath o Buccal pumping vs ram ventilation Evolution of vertebrate lungs o Originated 450 mya in bony fishes as outpouching from gut wall in O2 poor habitats o Allow gas exchange in oxygen poor aquatic habitats and on land O2 diffuses across respiratory membranes What happened to outpockets o Ray finned fishes gas bladders o Lobe finned fishes lungs eventually gave rise to terapods o Longs of vertebrates are homologous to gas bladders of fish but not to gills Functions of the mammal respiratory system o Gas exchange o Smell o Sound o Maintains homeostasis Eliminates excess heat and water Adjusts acid base Mammal respiratory system o Some commonalities in mammalian respiratory systems but are some unique features for each group as well Quiz Inspiration is an active process and exhalation is a passive process true or false true Evolution of the blowhole o Dolphin fetus Embryonic shift in nasal openings o Gray whale Evolutionary shift in nasal openings Whale respiratory adaptations o Actually have proportionately smaller lungs than terrestrial counterparts relative to their body size o Large tidal volume amount of oxygen exchanged when breathing in and out 85 90 of air humans only exchange 15 o Larger red blood cells and more of them o More myoglobin O2 binding molecule in muscles than terrestrial mammals table whales have way more O2 in muscles than humans o Oxygen shunted away from non vital organs during dives o Anaerobic muscle function high tolerance for lactic acid o Can tolerate high CO2 in blood Quiz what 2 structures are next to one another in the mammalian lung site of gas exchange Bronchial tubes and blood vessels bronchial tubes and capillaries alveoli and capillaries or alveoli and bronchial tubes alveoli and capillaries Oxygen transport o Blood cannot carry enough O2 in dissolved form to satisfy demands o Most oxygen is carried bound to hemoglobin in red blood cells o Hemoglobin has a great affinity for oxygen when it is at high partial pressures will bind with oxygen easily under good conditions Carbon Dioxide transport o Small amount of dissolves in blood 10 o More oxygen more acidic o Some binds to hemoglobin o Most CO2 is transported as bicarbonate 60 o Carbonic anhydrase is enzyme that enhances Rx found in red blood cells o Hemoglobin buffers blood by taking up CO2 so Rx moves to left and removes H o Inefficient Control of Breathing o Medulla oblongata sets main rhythm centers in pons fine tune it o Magnitude of breathing depends on concentration of oxygen and H o Brain detects excess H increases breathing o Carotid bodies and aortic bodies in arteries detect drop in oxygen increase breathing How do whales sleep o Unconscious vs conscious breathers o Humans are unconscious breathers o Whales are conscious breathers turn off half of their brain left side is active when right side is asleep right side is active when left slide is asleep Electroencephalography Dolphins in sleep state for 8 hours per day Oxygen dissociation curves describe binding of oxygen to hemoglobin o Shape of curve describes how readily hemoglobin acquires and releases O2 o Shifting curve to the right is decreasing the affinity of hemoglobin and vice versa for shifting to the left Shifting dissociation curves o More CO2 decrease pH more acidic warmer temperature o To the left higher affinity by lower temps by increasing pH o To the right lower affinity by higher temps by decrease in pH o Shift in dissociation curve with pH is known as the Bohr effect o Bohr effect shift of hemoglobin s ability to bind to oxygen More Co2 decrease pH warm the seas the curve would shift right hemoglobin wont bind to oxygen Bird graph high altitude species has less oxygen so the hemoglobin has adapted to bind to O2 better more so the curve shifts left o Low altitude species Quiz In deeply diving animals the situation where dissolved nitrogen disrupts nervous signaling causing a drowsy euphoric feeling is called nitrogen narcosis Deep sea divers nitrogen narcosis o Pressure causes increased nitrogen to dissolve into cell membrane lipid bilayer o Signal propagation in neural membranes is disrupted o Leads to drowsiness euphoria tipsy comatose below 106 122 meters The bends Continue taking notes from online Myoglobin s ability to hang onto O2 does not depend on the concentration of oxygen Bird respiration Migrating animals add new depth to how the ocean breathes Podcast o Dead zone hypoxic area o Primary cause of dead zones excess nutrient pollution o Amount of water flowing from Mississippi will determine how large the dead zone is o