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Questions and Answers
According to the provided information, what is the primary challenge for air breathers regarding CO2 excretion?
According to the provided information, what is the primary challenge for air breathers regarding CO2 excretion?
According to the provided content, where are peripheral chemoreceptors located in mammals?
According to the provided content, where are peripheral chemoreceptors located in mammals?
Based on the context provided, what is the main anatomical adaptation for gas exchange in bimodal breathers?
Based on the context provided, what is the main anatomical adaptation for gas exchange in bimodal breathers?
Which of the following best describes the method of CO2 excretion for most water breathers?
Which of the following best describes the method of CO2 excretion for most water breathers?
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According to the provided information, what is the primary means of O2 uptake for most bimodal breathers?
According to the provided information, what is the primary means of O2 uptake for most bimodal breathers?
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According to the content provided, what chemical reaction is important in the context of CO2 in aquatic species?
According to the content provided, what chemical reaction is important in the context of CO2 in aquatic species?
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What is the primary function of carbonic anhydrase within red blood cells?
What is the primary function of carbonic anhydrase within red blood cells?
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Based on the content, what mechanism does the equation $J = D \times A \times \frac{P1 - P2}{X}$ describe?
Based on the content, what mechanism does the equation $J = D \times A \times \frac{P1 - P2}{X}$ describe?
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How is the majority of CO2 transported in the blood?
How is the majority of CO2 transported in the blood?
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According to the provided information, freshwater fish mainly excrete which type of nitrogenous waste?
According to the provided information, freshwater fish mainly excrete which type of nitrogenous waste?
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In working tissues, what is the immediate effect of increased CO2 concentration inside red blood cells?
In working tissues, what is the immediate effect of increased CO2 concentration inside red blood cells?
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What role does the 'band 3' protein play in CO2 transport at the level of red blood cells?
What role does the 'band 3' protein play in CO2 transport at the level of red blood cells?
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Where does the conversion of bicarbonate back to CO2 primarily occur, during gas exchange?
Where does the conversion of bicarbonate back to CO2 primarily occur, during gas exchange?
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What is the direct consequence of the conversion of H2CO3 to CO2 and H2O at the respiratory surface of the lungs/gills with respect to direction of CO2 movement?
What is the direct consequence of the conversion of H2CO3 to CO2 and H2O at the respiratory surface of the lungs/gills with respect to direction of CO2 movement?
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In the context of the hemoglobin-oxygen binding curve, what does P50 represent?
In the context of the hemoglobin-oxygen binding curve, what does P50 represent?
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Considering all the reactions shown in the material provided, which of the following would best explain the direction of the equilibrium?
Considering all the reactions shown in the material provided, which of the following would best explain the direction of the equilibrium?
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Study Notes
Lecture 6: Gas Exchange
- Lecture date: January 17
- Topics covered: CO₂ exchange, regulating breathing
- Readings for review: pages 654-677, 620-638, 677-685
Respiratory Pigments
- Covered in Bio 2601
- Students expected to know hematocrit
- Whole blood consists of plasma (~55% of blood volume) and components separated by centrifugation
- Components include white blood cells (<1% of blood volume) and red blood cells/erythrocytes (~45% of blood volume).
Antarctic Icefish
- Lives at -1.9°C
- Lacks respiratory pigments.
- How does it obtain enough oxygen?
- Possible advantages of not having pigments?
- Other animals that do not require pigments?
- Shows data on oxygen solubility with temperature
Pigments & O₂ Carrying Capacity
- Graph showing the relationship between partial pressure of oxygen (PO₂) and the milliliters of oxygen per 100 mL of blood (volume %); also for total oxygen
- Oxygen equilibrium curve (total O₂).
- P₅₀ (pressure of oxygen at 50% saturation) relates to hemoglobin content
- Higher hemoglobin content equates to a lower P₅₀ Note: Data for figures include partial pressure of O₂ units of measurement (mm Hg and/or kPa) and corresponding quantities of oxygen.
Percent Saturation and Partial Pressure of O₂
- Graph showing the relationship between percentage saturation of hemoglobin, along with the partial pressure of O₂. This shows the percentage saturation of hemoglobin at different partial pressures
- P₅₀ represents partial pressure of O₂ where hemoglobin is 50% saturated
Oxygen Concentration of Blood and Partial Pressure of O₂
- Graph illustrating oxygen concentration in blood (mL O₂ / 100mL) in relation to the partial pressure of oxygen
- Shows oxygen concentration in blood at rest and during exercise, correlating with the partial pressures, including lungs at rest and exercise
CO₂ Excretion
- Location of CO₂ production
- Free diffusion of CO₂ across epithelia/membranes
- Limited solubility of CO₂ in the form it exists
- CO₂ being interconvertible to HCO₃ (bicarbonate)
- Carbonic anhydrase function within RBC
- Primary transport of CO₂ as HCO₃⁻
CO₂ Excretion: Working Tissues
- CO₂ diffuses from tissue to plasma and red blood cells
- CO₂ conversion to H₂CO₃ via carbonic anhydrase
- Conversion of H₂CO₃ to HCO₃⁻ and H⁺
- Effect on hemoglobin (Hb), including the name of this effect
- HCO₃⁻ transport in blood plasma
- Role of band 3 in maintaining a concentration gradient for exchange of chloride (Cl⁻) for bicarbonate
- Transport of CO₂ in plasma as HCO₃⁻
CO₂ Excretion: Gas Exchange Surface
- HCO₃⁻ limitation in diffusion across membranes
- Re-conversion of HCO₃⁻ to CO₂
- Effect on equilibrium and process behind this conversion
- Importance of diffusion for CO₂ removal
CO₂ Excretion: Air Breathers
- Difficulty in excreting CO₂ with low CO₂ in air
- Need for high pCO₂ for diffusion
- Data interpreted: Relationships between CO₂ partial pressure and oxygen partial pressure
Blood Gases & Breathing
- Chemoreceptors (peripheral and central) for regulating breathing
- Peripheral chemoreceptors locations (carotid and aortic bodies)
- Role of central chemoreceptors (medulla)
- Most important factor in regulating breathing
What Regulates Breathing?
- Interpretation of data related to air-breathers versus water-breathers for volume relations
Unusual Air-Breathers
- Where CO2 might create challenges for air breathers
- Methods employed to cope with high CO₂ concentrations
CO₂ Excretion: Water Breathers
- Easy excretion of CO₂ in water due to low CO₂ concentrations
- What happens to excreted CO₂
- Consequences of CO₂ excretion
- Chemical formula describing CO₂ reaction with water
What About Water Breathers?
- Discussion on chemoreceptors involved in respiratory reflexes in neotropical fish
- Data on results for animal testing, relating to P₅₀ values
Gas Exchange: Bimodal Breathers
- Two respiratory systems, air and water, in some animals
- Re-routing of blood for gas exchange
Gas Exchange: Skin Breathers
- O₂ uptake through lungs and permeable skin in water-based animals
- CO₂ excretion interpretative data; correlation between O₂ uptake and CO₂ excretion among different life stages in relation to respiration
- Data relating to different developmental and environmental characteristics.
Unusual Water Breathers
- Nitrogenous wastes in freshwater fish
- NH₃ diffusion across gills and the forms of NH4+
- "Soda Lake" environment and CO₂, bicarbonate, and pH correlations
- Effects of high pH on CO₂ and NH₄⁺ diffusion
- Other species, such as tilapia, are discussed
Ornithine-Urea Cycle
- Biochemical pathway for urea synthesis
- Diagram of biochemical reactions, including relevant enzymes such as glutaminase and glutamate, asparate and arginine.
- Molecules involved in the cycle, including glutamine, glutamate, 2-oxoglutarate, carbamoyl phosphate, ornithine.
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Description
Explore the intricacies of gas exchange as discussed in Lecture 6. This quiz covers topics such as CO₂ exchange, respiratory pigments, and the unique adaptations of Antarctic Icefish. Dive into the relationship between oxygen solubility and temperature, as well as the oxygen carrying capacity of blood.
