CR W1 Oxygen and carbon dioxide transport in the blood Quiz
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Questions and Answers

Which molecule is the primary form in which most carbon dioxide is carried back to the lungs?

  • Carbon monoxide
  • Bicarbonate (correct)
  • Carbaminohemoglobin
  • Dissolved gas

    • What is the main process that occurs in the lungs with respect to oxygen and carbon dioxide?

  • Oxygen picked up/CO2 released
  • Oxygen unloaded/CO2 loaded
  • Oxygen loaded/CO2 unloaded (correct)
  • Oxygen released/CO2 picked up

    • What is the significance of methaemoglobin in erythrocytes?

  • It decreases oxygen-carrying capacity (correct)
  • It increases oxygen-carrying capacity
  • It has no effect on oxygen-carrying capacity
  • It enhances carbon dioxide transport

    • What is the primary form in which most carbon dioxide is transported by the blood?

    <p>Bicarbonate ions</p> Signup and view all the answers

    What is the main function of haemoglobin in gas exchange at the tissues?

    <p>Oxygen release and carbon dioxide pickup</p> Signup and view all the answers

    How is most carbon dioxide carried back to the lungs?

    <p>In the form of bicarbonate</p> Signup and view all the answers

    What is the significance of methaemoglobin in erythrocytes?

    <p>It is a form of haemoglobin that cannot bind to oxygen</p> Signup and view all the answers

    What is the role of red cells (erythrocytes) in oxygen transport?

    <p>They are specially designed to carry oxygen, protecting other molecules from oxidation</p> Signup and view all the answers

    What happens to the oxygen-haemoglobin dissociation curve under the influence of temperature and pH?

    <p>It shifts to the right with an increase in temperature and decrease in pH</p> Signup and view all the answers

    What is meant by haematocrit and how is it regulated?

    <p>Haematocrit refers to the percentage of red blood cells in the total blood volume and is regulated by erythropoietin</p> Signup and view all the answers

    What is a proper definition of oxidation?

    <p>'A loss of electrons'</p> Signup and view all the answers

    Why is carriage of oxygen a problem for most organic molecules?

    <p>'Oxygen is a powerful oxidising agent'</p> Signup and view all the answers

    What is the normal range of oxygen saturation values for healthy individuals at sea level?

    <p>96% to 99%</p> Signup and view all the answers

    What does an SaO2 value below 90% indicate?

    <p>Hypoxaemia</p> Signup and view all the answers

    What is the characteristic shape of the oxygen-haemoglobin dissociation curve in adults?

    <p>'S' shaped</p> Signup and view all the answers

    What effect does temperature have on the oxygen-haemoglobin dissociation curve?

    <p>Moves the curve to the right, unloading more oxygen</p> Signup and view all the answers

    What is myoglobin's role in muscle tissue?

    <p>Forms a 'buffer store' of oxygen in muscle</p> Signup and view all the answers

    How is the haematocrit regulated?

    <p>By the balance between erythropoiesis and the rate of red cell destruction</p> Signup and view all the answers

    What is the primary function of erythrocytes?

    <p>Carrying oxygen from the lungs to the body's tissues</p> Signup and view all the answers

    What is the process of oxidation in the body?

    <p>The process of losing electrons</p> Signup and view all the answers

    What is the primary electron acceptor in oxidation processes?

    <p>Oxygen</p> Signup and view all the answers

    What is the condition characterized by smaller-than-normal red blood cells?

    <p>Microcytic anaemia</p> Signup and view all the answers

    What is the molecule responsible for reversibly binding oxygen in erythrocytes?

    <p>Haemoglobin</p> Signup and view all the answers

    What is the iron state in the haeme group of haemoglobin?

    <p>Ferrous iron (Fe2+)</p> Signup and view all the answers

    What is the byproduct of haemoglobin with oxidized iron that cannot bind oxygen?

    <p>Methaemoglobin</p> Signup and view all the answers

    What small molecule binds to haemoglobin and enhances oxygen release in hypoxic tissues?

    <p>2,3 DPG</p> Signup and view all the answers

    What is the measure of the percentage of red blood cells in the blood?

    <p>Haematocrit</p> Signup and view all the answers

    What causes sickle cell anaemia?

    <p>Mutation in the haemoglobin gene</p> Signup and view all the answers

    What is the composition of adult haemoglobin (haemoglobin A)?

    <p>Two α and two β subunits</p> Signup and view all the answers

    What is 2,3 DPG's role in relation to haemoglobin?

    <p>Enhances oxygen release in hypoxic tissues</p> Signup and view all the answers

    What is the significance of methaemoglobin in erythrocytes?

    <p>It is a form of haemoglobin that cannot bind oxygen effectively</p> Signup and view all the answers

    What is the primary role of red cells (erythrocytes) in oxygen transport?

    <p>To carry oxygen to tissues while minimizing oxidation damage</p> Signup and view all the answers

    What is the main function of haemoglobin in gas exchange at the tissues?

    <p>To release oxygen and pick up carbon dioxide</p> Signup and view all the answers

    What causes sickle cell anaemia?

    <p>A mutation in the haemoglobin gene resulting in abnormal haemoglobin structure</p> Signup and view all the answers

    What is meant by haematocrit and how is it regulated?

    <p>Haematocrit refers to the percentage of red blood cells in the blood and is regulated by erythropoietin levels</p> Signup and view all the answers

    What is the composition of adult haemoglobin (haemoglobin A)?

    <p>Two alpha and two beta subunits</p> Signup and view all the answers

    Which molecule is the primary form in which most carbon dioxide is transported by the blood?

    <p>Bicarbonate ions</p> Signup and view all the answers

    What is the significance of methaemoglobin in erythrocytes?

    <p>Impairs oxygen transport</p> Signup and view all the answers

    What is meant by the haematocrit and how is it regulated?

    <p>The percentage of red blood cells in the blood; regulated by bone marrow</p> Signup and view all the answers

    What is the composition of adult haemoglobin (haemoglobin A)?

    <p>2 alpha and 2 beta subunits</p> Signup and view all the answers

    What happens to the oxygen-haemoglobin dissociation curve under the influence of temperature and pH?

    <p>Shifts to the right with increased temperature and decreased pH</p> Signup and view all the answers

    What is the main function of haemoglobin in gas exchange at the tissues?

    <p>Facilitating exchange of both oxygen and carbon dioxide</p> Signup and view all the answers

    What is the primary form in which most carbon dioxide is transported by the blood?

    <p>Bicarbonate ions</p> Signup and view all the answers

    What is the characteristic shape of the oxygen-haemoglobin dissociation curve in adults?

    <p>Sigmoidal</p> Signup and view all the answers

    What is the iron state in the haeme group of haemoglobin?

    <p>Ferrous (Fe2+)</p> Signup and view all the answers

    What is 2,3 DPG's role in relation to haemoglobin?

    <p>Enhances oxygen release in hypoxic tissues</p> Signup and view all the answers

    What is the primary function of erythrocytes?

    <p>Carrying oxygen from the lungs to the body's tissues</p> Signup and view all the answers

    What is the characteristic shape of erythrocytes?

    <p>Biconcave disks</p> Signup and view all the answers

    What is the primary electron acceptor in oxidation processes?

    <p>Oxygen</p> Signup and view all the answers

    What is the condition characterized by larger-than-normal red blood cells?

    <p>Macrocytic anaemia</p> Signup and view all the answers

    What is the molecule responsible for reversibly binding oxygen in erythrocytes?

    <p>Haemoglobin</p> Signup and view all the answers

    What is the role of reticulocytes in circulation?

    <p>Immature red blood cells that change into mature red cells after entering circulation</p> Signup and view all the answers

    What effect does cold have on the oxygen-haemoglobin dissociation curve?

    <p>Moves the curve to the left, reducing oxygen unloading</p> Signup and view all the answers

    What is the primary role of erythropoietin (EPO)?

    <p>Regulates haematocrit and stimulates red blood cell production</p> Signup and view all the answers

    What is the significance of myoglobin in muscle tissue?

    <p>Acts as a buffer store with greater affinity for oxygen</p> Signup and view all the answers

    What does low pH and high CO2 levels do to the oxygen-haemoglobin dissociation curve?

    <p>Shifts it to the left, reducing oxygen unloading</p> Signup and view all the answers

    How does haematocrit regulate the amount of oxygen carried in the blood?

    <p>By determining the percentage of red blood cells in the blood</p> Signup and view all the answers

    What is the primary form in which carbon dioxide is carried to the lungs for elimination?

    <p>As bicarbonate, after conversion by carbonic anhydrase in RBCs</p> Signup and view all the answers

    Study Notes

    • Haemoglobin is a protein in red blood cells that binds oxygen through a weak reversible bond due to steric hindrance.

    • Oxygen bonding happens at the four haeme sites, with each subsequent bonding becoming easier due to structural changes in the protein.

    • Methaemoglobin is formed when the steric hindrance is not sufficient, and the oxygen oxidizes the iron, making the haemoglobin unable to carry oxygen.

    • Normally, 1-2% of haemoglobin is methaemoglobin, but higher percentages can be genetic or caused by chemicals and is known as methaemoglobinemia.

    • Haemoglobin is made up of two α and two β subunits (haemoglobin A) in adults, with foetal haemoglobin having two Υ subunits (haemoglobin F) in the foetus and newborns.

    • 2,3 DPG (2-3 diphosphoglycerate) is a small molecule that binds to haemoglobin and enhances oxygen release in hypoxic tissues.

    • Percent saturation, or the proportion of haemoglobin bound to oxygen, is an important indicator of oxygen transport in the body.

    • Haemoglobin's oxygen-binding properties change under the influence of temperature and pH, with the oxygen dissociation curve showing the relationship between these factors and oxygen saturation.

    • The haematocrit is a measure of the percentage of red blood cells in the blood, and is regulated through various mechanisms to maintain optimal oxygen transport.

    • Haemoglobin plays a crucial role in the transport of carbon dioxide in the form of carbaminohaemoglobin and methemoglobin.

    • Sickle cell anaemia is a genetic disorder caused by a mutation in the haemoglobin gene that leads to the formation of sickle-shaped red blood cells and increased susceptibility to malaria.

    • The haemoglobin molecule consists of a haeme group and globin subunits, and the specific arrangement and steric hindrance of the subunits determine its oxygen-binding properties.

    • Haemoglobin's unique structure and properties allow it to efficiently bind and transport oxygen in the blood.

    • Foetal haemoglobin has a higher affinity for oxygen than adult haemoglobin, enabling it to extract oxygen from the placental blood during fetal development.

    • Methaemoglobin is a byproduct of haemoglobin with oxidized iron that cannot bind oxygen and is gradually formed as red blood cells age.

    • Congenital deficiency of methaemoglobin reductase can lead to an increased amount of methaemoglobin in the blood, but affected individuals can still effectively transport oxygen due to polycythemia.

    • The single mutation in the haemoglobin gene that causes sickle cell anaemia leads to the formation of sickle-shaped red blood cells that are not susceptible to malaria parasites.

    • Haemoglobin is a complex protein that plays a critical role in the transport of oxygen and carbon dioxide in the body, and its properties are influenced by various factors such as temperature, pH, and the presence of small molecules like 2,3 DPG.

    • Pulse oximeter measures oxygen saturation (SaO2) in blood.

    • Healthy individuals at sea level have SaO2 between 96% and 99%, above 94%.

    • Hypoxemia is an SaO2 below 90%.

    • Oxygen saturation does not directly reflect tissue oxygenation.

    • Oxygen unloading determined by Oxygen-haemoglobin dissociation curve.

    • Haemoglobin (Hb) binds oxygen cooperatively to its subunits.

    • S-shaped curve is flat at high pO2, steep at medium and low pO2.

    • Temperature, pH, and myoglobin affect the oxygen-haemoglobin dissociation curve.

    • Heat moves curve to the right, unloading more oxygen at given pO2.

    • Cold moves curve to the left, reducing oxygen unloading.

    • Myoglobin in muscle has a greater affinity for oxygen, forming a buffer store.

    • Myoglobin release from damaged muscle called rhabdomyolysis and causes acute renal failure.

    • Haematocrit (percentage of blood that is red blood cells) regulates the amount of oxygen carried.

    • Erythropoietin (EPO) is a hormone that regulates the haematocrit and stimulates red blood cell production.

    • Red blood cells transport carbon dioxide back to the lungs for elimination.

    • Carbonic anhydrase (CA) converts CO2 to bicarbonate in RBCs, and the bicarbonate is carried to the lungs.

    • Chloride ions enter RBCs to maintain electrical neutrality when bicarbonate is expelled.

    • CO2 is also carried to the lungs as carbaminohaemoglobin, but this transport is not as important as bicarbonate transport.

    • Low pH and high CO2 levels shift the oxygen-haemoglobin dissociation curve to the left, reducing oxygen unloading.

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    Oxygen And Carbon Dioxide Transport In Blood (Queen Mary 2023 PDF)

    Description

    Test your knowledge about the weak reversible bond formed between oxygen and the sixth ferrous electron in the haeme group of haemoglobin. Learn how steric hindrance affects oxygen bonding and the critical dependency of oxygen bonding on the molecular structure.

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