1957152
Descripción
Fichas por Sarah Mills, actualizado hace más de 1 año
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Creado por Sarah Mills
hace casi 10 años
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| Pregunta | Respuesta |
| When does Hb bind O2 in the lungs? | When PO2 is high |
| When does Hb unbind O2 in the tissues? | Where PO2 is low |
| What does cooperativity mean? | Once one O2 has bound to a Hb it is easier for subsequent O2 to bind |
| Is oxygen soluble in plasma? | Poorly (normal arterial blood carries 70x more O2 on Hb (on RBC's) than in the plasma |
| What is the function of Hb? | To carry O2 |
| How many ATP are produced in aerobic resp? | ~36 |
| How many ATP are produced in anaerobic resp? | 4 net 2 |
| How much of the weight of RBC's does b take up? | 95% |
| Describe haem (3) | Coloured, contains one iron atom, is the site of O2 binding |
| How many subunits does myoglobin have? | 1 |
| How many subunits does Hb have? | 4 Adult: 2 alpha, 2 beta Foetal: 2 alpha, 2 gamma |
| What is a tetramer? | A protein with four peptide subunits |
| What is the bohr effect? | Increase in CO2 decreased Hb affinity for O2 Decreased blood pH (due to CO2) leads to decreased affinity for O2 High blood CO2 means low blood pH |
| How much CO2 is dissolved in blood? | 10% |
| How much CO2 is carried as carbamino? | 22% |
| How much CO2 is carried as HCO3-? | 68% |
| Why is myoglobin curve hyperbolic? | It can only bind one O2 before it becomes saturated |
| Why is the Hb curve sigmoidal in shape? | It has 4 spaces for O2 - as one binds it makes it easier for the subsequent O2 to bind |
| What causes decrease in affinity for O2? | Rightward shift |
| What leads to rightward shift? | CO2 H+ Cl- 2,3-DPG |
| What is 2,3-DPG? | 2,3-diphosphoglycerate Binds to Hb Lowers affinity of Hb for O2 Found in erythrocytes Tiny molecule |
| What affinity does foetal Hb have for 2,3-DPG? | Low therefore foetal Hb has a higher affinity for O2 than adult Hb |
| Describe active muscles | O2 levels are low CO2 levels are high Blood is slightly acidic Temperature is higher There is myoglobin (Hb in muscle) |
| What happens as blood runs along the capillary? | O2 leaves the capillary CO2 and H+ bind to the Hb and Hb saturation is shifted to the right HCO3- leaves the RBC and enters the plasma Cl- leaves the plasma and enters RBC (chloride shift) |
| How is breathing controlled? | CO2 gas enters the cerebrospinal fluid (CSF) and makes carbonic acid The H+ is picked up by the brain as the medulla samples the CSF as well as the interstitial fluid |
| What do RBC's look like? | Mature Biconcave disc Lack of organelles 7um diameter 2um height Contain Hb Red when oxygenated |
| What is the function of RBC's? | Transport O2 and CO2 Fold and stack in blood vessels called rouleau Survive around 120 days |
| How many RBC's per uL blood? | 5,000,000 |
| How many leukocytes per uL blood? | 9,000 |
| How many platelets per uL blood? | 300,000 |
| What is haematocrit? | The packed cell volume |
| What are normal Hb levels for a man? | 13-17g/dL |
| What are normal Hb levels for a woman? | 12-16g/dL |
| What is the mean cell Hb value? | 27-34 pg |
| What is the mean corpuscular volume? | 80-100 fL |
| What is erythropoiesis? | Development of RBC's |
| When a baby is growing where do RBC's develop? | Liver Spleen Yolk sac Lymph nodes |
| What is erythropoietin? | The protein responsible for RBC growth |
| What are the precursors to RBC's? | Erythroblasts - Reticulocytes - RBC's |
| How long do reticulocytes last in the blood? | 2 days |
| Why are reticulocytes important in anaemia? | Indicator of bone marrow activity High in haemolytic anaemias (where blood cells are broken down prematurely) Low when erythropoeisis is low Machine counts cells and detects those with DNA in them |
| What is methaemoglobinaemia? | Hb cannot transport O2 Fe is Hb is oxidised Due to globin mutaton, hereditary decrease in NADH or toxic substances |
| What is carbon monoxide poisoning? | Hb cannot transport O2 CO displaces O2 from Hb Affinity for CO is 250x stronger than that for O2 Blood turns bright red Leads to disorientation and death |
| What is polycythaemia? (general) | Increased number of RBC's Increased velocity of blood Blood vessels become clogged |
| What is physiological polycythaemia? | Occurs when living at high altitudes |
| What is polycythaemia vera? | Often asymptomatic Risk of thrombotic events No cure Treat with blood letting (venesection) Increases with age Possibly genetic |
| How is Fe stored intracellularly? | As ferritin and haemosiderin |
| Where is Fe stored in the body? | Liver Spleen Erythrocytes Bone marrow Macrophages Monocytes |
| What can iron deficiency lead to? | Iron deficient anaemia |
| What is vitamin B12 and Folic acid essential for? | Rapidly dividing tissue |
| What does Vitamin B12 and Folic acid deficiency cause? | Megaloblastic cells (massive cells which are fragile) |
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