22108456
Description
Flashcards by Evian Chai, updated more than 1 year ago
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Created by Evian Chai
over 4 years ago
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| Question | Answer |
| What is the composition of DRY AIR (as split into N2, O2, and CO2? | N2: 79% O2: 21% CO2: <0.04% |
| [...] O2 extracted from blood/min and consumed by tissues/min ... CO2 produced per min and expired/min | 1. 250mL 2. 200mL |
| The Respiratory quotient is | CO2 Produced (200)/O2 Consumed (250)=0.8 |
| Pressure of a gas is proportional to | Temperature+ concentration (#of gas molecules in a given volume) |
| According to Dalton's Law, partial pressure it the pressure of a specific gas based on what? What is the total pressure? | Its % in the air The sum of the individual partial pressures |
| The driving force determining the rate of gaseous transfer/diffusion is? | Partial pressure differences Diffusion occurs form high partial pressure to low partial pressure |
| What is diffusion limited by? | 1. Solubility of gas in a fluid 2. Diffusion barrier thickeness (in this case alveolar+capillary epithelium) |
| Transfer rate is equal to | (Area/thickness) X (P1-P2) X (solubility) X (1/Root Mol. Weight) |
| In regards to pressure difference and solubility, how do O2/CO2 differ? | O2 has high pressure difference but low solubility CO2 has low pressure difference but high solubility |
| Systematic blood PO2 is determined by? | Alveolar pO2 (where O2 comes from) |
| Alveolar pCO2 is determined by | Capillary blood pCO2 (where co2 is delivered from) |
| In most cases, transfer of gases and rapid and equilibirum is reached .... of the way along pulmonary capillary | 1/3 |
| Why is systematic arterial pO2 slightly lower than alveolar pO2? | The anatomical right to left shunt, wherein deoxygenated blood from bronchial vein mixes with oxygenated blood in the pulmonary vein |
| What are 4 measures of oxygen transport? | 1. % saturation of hemoglobin binding sites 2. O2 content in blood (O2 on haemoglobin+dissolved in blood) 3. Max O2 carrying capacity 4. Partial pressure of oxygen |
| How many protein subunits is haemoglobin made of? What do each of these subunits contain? | 4 subunits Each contain own haem group with Fe2+ binding site for histidine+O2 molecule |
| Why is haemoglobin needed for blood transport? | Low solubility of O2 |
| What are the three factors influencing the structure of Hb? | 1. pH/pCO2 2. Temperature 3. 2,3 diphosphoglycerate |
| The Hb disassosiation curve shifts LEFT when what happens to the following: pCO2 pH Temp 2,3 DPG Where does this happen and what happens to affinity? | pCO2 drops at alveoli pH rises Temperature drops due to evaporation 2,3 DPG decreases increased affinity, occurs in alveoli |
| The Hb disassosiation curve shifts RIGHT when what happens to the following: pCO2 pH Temp 2,3 DPG Where does this happen and what happens to affinity? | pCO2 rises at muscles pH drops Temp rises 2,3 DPG increases bc byproduct of glycolysis At muscles, affinity lowers to aid O2 unloading |
| What are the 3 forms of CO2 transport in the blood? | 1. Dissolved in plasma 2. As bicarbonate (majority) 3. Carboamino compounds (in venous blood mostly) |
| What are the two ways CO2 is transported as bicarbonate? | In plasma, where CO2+H20-->H2CO3-->H+HCO3 2. CO2 taken up by tissues due to PCO2 gradient, then enters RBC where it becomes H++ HCO3- |
| What speeds up the reaction of CO2+H20-->H2CO3-->H+HCO3? | carbonic anhydrase |
| The Chloride Shift forms the PCO2 gradient in RBC by | Pumping OUT HCO3- in exchange for Cl- |
| Haldane Effect A creates the pCO2 gradient in RBC by | DeoxyHb buffer H+, lowering H+ in the cell |
| How is the pCO2 gradient formed in the RBC? (3) | 1. Chloride Shift 2. Haldane effect A 3. Haldane effect B (for carboamino acids) |
| How does Haldane Effect B create the pCO2 in RBC for carboaminos? | In RBC, CO2+NH2 groups of lysine/arginine combine to form RNHCOOH This decreases CO2 levels, so more CO2 is uptaken into the RBC Occurs more readily in deoxyHb |
| The Haldane Effect states that at any pCO2, quantity of CO2 carried in venous blood [...] arterial blood because | Is more than - due to Haldane Effect A/B in deoxyHb 1. Better buffering of H+ by deoxy-Hb shifts rxn left, decreasing CO2 (A) 2. Hb forms carboamino compounds with CO2 more readily when deoxygenated (B) Both decrease CO2 in RBC, aiding uptake from tissues |
| How does the pCO2 gradient in lungs relate to the gradient in blood? Why? | It is reversed due to Haldane effect operating in reverse: -HCO3- is converted back to CO2 - CO2 released from carboaminoacids So less CO2 in blood in lungs |
| The Gap in the CO2 disassosiaton curve represents the... | Haldane Effect |
| Normal Arterial Blood: pCO2...kPa ...mL CO2/dl (vs. 20mL/dl for O2) 97% O2 Sat Mixed venous blood: PCO2...kPa ...mL CO2/dl 75% O2 Sat | 5.3 48 6.1 52 |
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