11814419
Description
Flashcards by J yadonknow, updated more than 1 year ago
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Created by J yadonknow
almost 7 years ago
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| Question | Answer |
| Where do the pleural membranes of the lung meet? | At the hilum of the lung |
| What is the pressure within this closed pleural space w.r.t atmospheric pressure? | Pressure is negative |
| How does the Pulmonary Circulation run w.r.t the Systemic Circulation? | Pulmonary Circulation runs in series with the Systemic Circulation |
| Describe Pulmonary Circulation | Pulmonary circulation: RV-> LUNGS -> LA from right ventricle to lungs via pulmonary arteries From lungs to left atrium of the heart via pulmonary vein |
| Describe Systemic Circulation | LV->BODY->RA Blood flows from left ventricle to cells of body via systemic arteries Flows from body to right artery of the heart via systemic veins |
| What is the pressure like in Pulmonary Circulation? What does this facilitate? | Pressure in Pulmonary Circulation are very low Slow flow rate allows efficient Mx |
| How do the Pulmonary arteries assist in Mx? | Pulmonary arterial walls are thin Pulmonary vascular resistance is low (R squeezes out material from blood, a sponge that's not being wrung will just soak) |
| Show an equation that allows us to formulate Vascular Resistance | (InP - OutP)/Blood Flow |
| How does gravity influence ventilation and perfusion in humans? | At rest, bottom of lung is rich in blood and oxygen Perfusion and ventilation decreases as you go towards top of the lung |
| How do alveoli differ depending on the region of the lung? | Alveoli at bottom of lung expand less than those at top |
| What is VA? | Alveolar ventilation rate, volume of fresh air available for Gx per minute |
| What is Q? | Rate of blood flow/volume of blood available passing through Pulmonary Circulation |
| Why does regional VA:Q vary across the lung? | At bottom of lung BF/AF at top AF/BF Top part of lung much higher AF/BF, not really participating in gas exchange |
| Why is regional mapping necessary? | Blood flow 3x faster than ventilation, also changes in BF/lung ventilation depending on area |
| How does regional VA:Q vary? | Regional VA:Q can vary from 0 to infinty |
| What occurs at 0? | No ventilation, no gas exchange Blood crosses lung without coming into contact with alveolar air (right to left shunt) |
| What happens at infinity? | Anatomical dead space, or ventilated alveoli that are not perfused |
| Why is local matching important? | Local matching of ventilation and perfusion is important to optimise Gx in the lungs The ratio is kept near 1:1 on the local scale |
| What is modulated for VA:Q matching? | Blood flow |
| What effect does low PO2 have on blood flow? | Vasoconstriction occurs as a result of hypoxia Blood is directed away from poorly-ventilated areas The response is very non-linear |
| How does vasoconstriction halt blood flow? | Resistance increases prevents blood from flowing to that part of the lung |
| Why is blood flow restricted from accessing these areas of the lung? | These areas aren't ventilated, so gas exchange can't occur well and the blood would just shunt through |
| How do fish maximise Gx? | Countercurrent flow |
| How do bird lungs maximise Gx? | Bird lungs have continous airflow over the respiratory interface Air capillaries and blood capillaries are adjacent so fresh air continuously flows over the gas exchange surface |
| Show the efficacy of Gx of fish mammals and birds | mammals<birds<fish tidal bulk flow: unidrectional flow: countercurrent flow |
| Diagram of alveolus | bam |
| Describe movement of air through an alveolus | Dissolve in liquid layer lining the alveolus Alveolar wall -> IS Space -> BC -> Plasma |
| How is transfer of O2 further influenced? | Influenced by diffusion across the RBC membrane Combines with haemoglobin (diagram) |
| How fast is this transfer of O2? | Very fast |
| What is Hb? | Four polypeptide subunit haem group at the centre |
| Describe Hb-O2 dissociation curve | Sigmoidal (S) curve Initially pp O2 increases and O2 binds to first haem group Once 1 O2 is bound to Hb co-operative binding occurs Easier for next O2 to bind, increased O2 affinity |
| What is meant by deoxygenated blood? | Not fully complexed with oxygen |
| Describe the Bohr Shift | Increase in PCO2 causes a shift to the right of the curve Increase in PCO2 signifies an increase in respiration increased metabolic demand Lowers affinity of Hb towards O2 causes a dissociation |
| What other factors also cause an increase in O2 dissociation? (3) | Increased H+ Increased temperature Increased 2-3BPG |
| Name 3 respiratory pigments and their characteristics | Haemoglobin 4 Fe-containing haem groups Myoglobin - similar to single Hb subunit Haemocyanin - Cu containing molecule, packaged in cells "blue blood" |
| How does myoglobin function as an O2 reserve? | Myoglobin has a very high affinity for O2, doesn't dissociate easily |
| What is meant by P50 on an oxygen dissociation curve? | 'Environmental' PO2 at which Hb is 50% saturated |
| How does foetal Hb differ from maternal Hb? | Higher O2 affinity, so can collect O2 from maternal Hb |
| Why is this important? | Lungs of foetus not functional Needs O2 supply |
| Draw a diagram showing O2 and CO2 exchange with the circulatory system and tissues of the body | blahblah blah |
| carbonic anhydrase | blah |
| How do CO2 levels alter pH of the cell? | Can form carbamino compounds on Hb, this is prevalent in the venus side of circulation |
| Haldone effect | H+ +HbO2 -> H+ + Hb + O2 |
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