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 approacheso CO2 and O2 can only cross cell membranes when they are dissolved in watero 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- Gillso 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 flowo Counter-currently exchange: blood and water are flowing opposite one another, increases efficiency in uptake of oxygen and release of carbon dioxide - Counter-current exchangeo Diagram: gas will naturally diffuse from water to blood b/c it will always go down the concentration gradiento 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 lungso Originated 450 mya in bony fishes as outpouching from gut wall in O2 poor habitatso 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 bladderso Lobe-finned fishes—lungs (eventually gave rise to terapods)o Longs of vertebrates are homologous to gas bladders of fish, but not togills- Functions of the mammal respiratory systemo Gas exchangeo Smello Soundo Maintains homeostasis Eliminates excess heat and water Adjusts acid-base…- Mammal respiratory systemo Some commonalities in mammalian respiratory systems, but are someunique features for each group as well- Quiz: Inspiration is an active process and exhalation is a passive process (trueor false) true- Evolution of the blowhole o Dolphin fetus: Embryonic shift in nasal openingso Gray whale: Evolutionary shift in nasal openings- Whale respiratory adaptationso 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 themo More myoglobin (O2 binding molecule in muscles) than terrestrial mammals (table) whales have way more O2 in muscles than humanso Oxygen shunted away from non-vital organs during diveso Anaerobic muscle function-high tolerance for lactic acido 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 transporto Blood cannot carry enough O2 in dissolved form to satisfy demandso Most oxygen is carried bound to hemoglobin in red blood cellso Hemoglobin has a great affinity for oxygen when it is at high partial pressures (will bind with oxygen easily under good conditions)- Carbon Dioxide transporto Small amount of dissolves in blood (10%)o More oxygen=more acidico Some binds to hemoglobino 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 Breathingo Medulla oblongata sets main rhythm, centers in pons fine-tune ito Magnitude of breathing depends on concentration of oxygen and H+o Brain detects excess H+, increases breathingo Carotid bodies and aortic bodies (in arteries) detect drop in oxygen, increase breathing- How do whales sleep?o Unconscious vs. conscious breatherso Humans are unconscious breatherso 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 O2o Shifting curve to the right is decreasing the affinity of hemoglobin and vice versa for shifting to the left- Shifting dissociation curveso More CO2, decrease pH, more acidic, warmer temperatureo To the left (higher affinity) by lower temps, by increasing pHo To the right (lower affinity) by higher temps, by decrease in pH o Shift in dissociation curve with pH is known as the Bohr effecto 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 lefto 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 narcosiso Pressure causes increased nitrogen to dissolve into cell membrane lipid bilayero Signal propagation in neural membranes is disruptedo 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”- Podcasto Dead zone-hypoxic areao Primary cause of dead zones-excess nutrient pollutiono Amount of water flowing from Mississippi will determine how large the dead zone