Blood Oxygen Capacity Calculation Quiz
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Questions and Answers

What is the role of hypoxic pulmonary vasoconstriction?

  • Decreases surface area for gas exchange
  • Redistributes blood flow to maintain a matched V/Q in the lungs (correct)
  • Enhances oxygen transport in the blood
  • Increases diffusion distance between the alveolus and the blood

    • According to Henry’s Law, what factor is proportional to the quantity of a slightly soluble gas that dissolves in a given mass of liquid at a particular temperature?

  • Concentration of other gases
  • Partial pressure of the gas (correct)
  • Volume of the liquid
  • Temperature of the liquid

    • Which statement is true about oxygen transport in the blood?

  • Physically dissolved O2 is relatively high in the blood
  • Hemoglobin can bind an unlimited amount of oxygen molecules
  • Oxygen in the blood is only chemically bound to hemoglobin
  • Hemoglobin can bind 4 molecules of O2 (correct)

    • What is the main cause of sickle cell disease?

    <p>Hemoglobin crystallization</p> Signup and view all the answers

    What does the Bohr effect describe?

    <p>Decrease in hemoglobin affinity for oxygen in alkaline environments</p> Signup and view all the answers

    What factor increases according to Fick's First Law of Diffusion to enhance diffusion rate?

    <p>Increased permeability</p> Signup and view all the answers

    In blood, what determines the oxygen-carrying capacity?

    <p>Quantity of Hb available for binding with oxygen</p> Signup and view all the answers

    How does carbon monoxide (CO) diffusing capacity compare to oxygen (O2) diffusing capacity?

    <p>~400-450 ml/min/mm Hg (20X greater than O2 diffusing capacity)</p> Signup and view all the answers

    What does Blood O2 content include?

    <p>Both physically dissolved O2 and blood O2 capacity</p> Signup and view all the answers

    What is the main purpose of hypoxic pulmonary vasoconstriction?

    <p>To prevent hypoxemia</p> Signup and view all the answers

    What can cause pulmonary vasoconstriction in the pulmonary circulation?

    <p>Low alveolar PO2</p> Signup and view all the answers

    In hypoxic pulmonary vasoconstriction, what happens when perfusion of a hypoventilated alveolus occurs?

    <p>Decreased PO2 and increased PCO2 in the blood entering the pulmonary vein</p> Signup and view all the answers

    When does the V/Q ratio equal 3?

    <p>When alveoli are ventilated, not perfused (alveolar dead space)</p> Signup and view all the answers

    What is the maximum amount of oxygen that can be carried in the blood?

    <p>20.1 mL O2/100 mL of blood</p> Signup and view all the answers

    Which factor is extremely important in influencing pulmonary vascular tone?

    <p>Local factors like hypoxia</p> Signup and view all the answers

    Which factor can cause a right shift in the oxyhemoglobin dissociation curve?

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

    What does the Bohr effect explain regarding oxygen release?

    <p>Why oxygen is less likely to be released in tissues with higher CO2 levels</p> Signup and view all the answers

    What is the main effect of hypoxic pulmonary vasoconstriction?

    <p>Preventing hypoxemia</p> Signup and view all the answers

    Which condition is characterized by insufficient oxygen in the blood?

    <p>Hypoxic hypoxia</p> Signup and view all the answers

    What percentage of carbon dioxide is transported in the blood as bicarbonate ions?

    <p>70%</p> Signup and view all the answers

    What does the P50 represent in the oxyhemoglobin dissociation curve?

    <p>PO2 at 50% Hb saturation</p> Signup and view all the answers

    Which factor can shift the oxyhemoglobin dissociation curve to the left?

    <p>Decreased pH</p> Signup and view all the answers

    What type of hypoxia results from decreased hemoglobin concentration?

    <p>Anemic hypoxia</p> Signup and view all the answers

    Which substance primarily combines with amine groups of blood proteins for carbon dioxide transport?

    <p>Carbamino compounds</p> Signup and view all the answers

    What is the main significance of the sigmoidal shape of the oxyhemoglobin dissociation curve?

    <p>It indicates cooperation between heme groups in oxygen binding.</p> Signup and view all the answers

    What type of blood flow occurs in zone 3 of the lung?

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

    Which part of the lung experiences more negative intrapleural pressures?

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

    Which alveoli in the lung are more compliant and undergo greater expansion during inspiration?

    <p>Lower lung</p> Signup and view all the answers

    What range does the normal V/Q ratio fall within in the lung?

    <p>0.8 - 1.2</p> Signup and view all the answers

    Where in the lung is the variation in perfusion greater?

    <p>Between upper and lower lung</p> Signup and view all the answers

    What does the O2-CO2 diagram illustrate regarding the Ventilation-Perfusion Relationship of the Lungs?

    <p>Gas exchange efficiency</p> Signup and view all the answers

    In the normal upright lung, why does blood flow per unit volume decrease from the bottom to the top of the lung?

    <p>Due to differences in hydrostatic pressure on the pulmonary vessels caused by gravity</p> Signup and view all the answers

    Which zone in the lung represents alveolar dead space due to alveolar air pressure occluding the pulmonary capillaries?

    <p>Zone 1</p> Signup and view all the answers

    What characterizes blood flow in Zone 2 of the lung according to the text?

    <p>Pulmonary capillary flow is intermittent and varies during respiration</p> Signup and view all the answers

    Which relationship determines blood flow distribution in the lungs according to the text?

    <p>Pulmonary capillary pressures and alveolar air pressure</p> Signup and view all the answers

    What does the Ventilation Perfusion-Relationship primarily determine according to the text?

    <p>Partial pressures of oxygen and carbon dioxide within alveoli and arterial blood</p> Signup and view all the answers

    How are regional variations in blood flow in the lung affected according to the text?

    <p>By differences in hydrostatic pressure due to gravity</p> Signup and view all the answers

    What is the primary factor contributing to airway resistance in the lungs?

    <p>Pulmonary tissue resistance</p> Signup and view all the answers

    Which structure in the lungs accounts for 90% of the airway resistance?

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

    What can cause dynamic airway compression in the bronchioles?

    <p>Contraction of expiratory muscles</p> Signup and view all the answers

    Which condition is characterized by bronchioles becoming a major source of airway resistance?

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

    What is the main cause of bronchoconstriction and bronchodilation in the airways?

    <p>Nervous system activation</p> Signup and view all the answers

    Which chemical signal is responsible for causing bronchiolar constriction in asthma?

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

    How does forced expiration lead to dynamic airway compression in the lungs?

    <p>Negative transpulmonary pressure values</p> Signup and view all the answers

    What is the main role of leukotrienes in asthma?

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

    Where does a negative transpulmonary pressure value lead to airway collapse in the lungs?

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

    Which structure's contraction results in dynamic airway compression at low lung volumes?

    <p>Expiratory muscles</p> Signup and view all the answers

    What is the maximum amount of oxygen that can be carried in the blood?

    <p>20.1 mL O2/100 mL of blood</p> Signup and view all the answers

    What does the P50 represent in the oxyhemoglobin dissociation curve?

    <p>The partial pressure of oxygen at which 50% of Hb is deoxyhemoglobin</p> Signup and view all the answers

    What factor can cause a left shift in the oxyhemoglobin dissociation curve?

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

    Which substance primarily combines with amine groups of blood proteins for carbon dioxide transport?

    <p>Carbamino compounds</p> Signup and view all the answers

    What is the main cause of hypoxia resulting from decreased hemoglobin concentration?

    <p>Anemic hypoxia</p> Signup and view all the answers

    What is hypoxemia?

    <p>Insufficient oxygen in the blood</p> Signup and view all the answers

    Under what conditions would there be a greater ability to release oxygen according to the oxyhemoglobin dissociation curve?

    <p>When it shifts to the right</p> Signup and view all the answers

    How does carbon monoxide (CO) diffusing capacity compare to oxygen (O2) diffusing capacity?

    <p>CO diffusing capacity is higher than O2 diffusing capacity</p> Signup and view all the answers

    What is the unit for the solubility coefficient of oxygen in the blood at a normal body temperature?

    <p>mL/100 mL</p> Signup and view all the answers

    How many abnormal variants of hemoglobin have been demonstrated in patients?

    <p>Around 100 variants</p> Signup and view all the answers

    What is the shape of red blood cells affected by HbS (sickle cell hemoglobin) when not combined with oxygen?

    <p>&quot;Sickle&quot; shape</p> Signup and view all the answers

    What is the formula to calculate blood O2 content at any partial pressure of oxygen (PO2)?

    <p>Physically dissolved O2 + Blood O2 capacity</p> Signup and view all the answers

    In pulmonary gas exchange, where does gas exchange in the respiratory units primarily occur?

    <p>At the alveolar-capillary membrane</p> Signup and view all the answers

    What is the main function of hypoxic pulmonary vasoconstriction?

    <p>Redistribute blood flow in the lungs</p> Signup and view all the answers

    What happens to blood viscosity if sickled shaped cells stick together in the blood?

    <p>Increases significantly</p> Signup and view all the answers

    Which law states that the quantity of a slightly soluble gas in a liquid is proportional to the partial pressure of that gas?

    <p>Henry's Law</p> Signup and view all the answers

    "Fick's First Law of Diffusion" states that the diffusion rate increases when which of the following increases?

    <p>Surface area, concentration gradient, and permeability</p> Signup and view all the answers

    What is the main component responsible for transporting oxygen in the blood?

    <p>Hemoglobin (Hb)</p> Signup and view all the answers

    Study Notes

    Ventilation and Perfusion in the Lungs

    • Ventilation and perfusion differ depending on the region of the lung
    • The balance between alveolar ventilation and perfusion determines the partial pressures of oxygen and carbon dioxide in the alveolus and, subsequently, in arterial blood

    Regional Variations in Blood Flow in the Lungs

    • Blood flow in the lungs is determined by the relationship between pulmonary capillary pressures (at the arterial and venous ends) and alveolar air pressure
    • In the normal upright lung, blood flow decreases from the bottom to the top due to differences in hydrostatic pressure (due to gravity) on pulmonary vessels
    • The lung can be divided into three zones based on alveolar, arterial, and venous pressures:
      • Zone 1: No blood flow (higher alveolar air pressures)
      • Zone 2: Intermittent blood flow (only with peak systolic pressures ~25mm Hg)
      • Zone 3: Blood flow occurs continuously

    Oxygen Transport in the Body

    • Oxygen is transported in the blood in two ways:
      • Physically dissolved oxygen (0.003 mL O2/100 mL blood at a PO2 of 40 mmHg)
      • Chemically bound to hemoglobin (Hb)
    • The oxyhemoglobin dissociation curve relates the percent of O2 saturation to the partial pressure of oxygen (PO2)
    • Factors that affect the oxyhemoglobin dissociation curve include:
      • Temperature
      • pH
      • 2,3-DPG
      • Anemia
      • Nitric oxide levels
      • Carbon monoxide levels
      • Presence of other forms of Hb (Methemoglobin and Fetal hemoglobin)

    Carbon Dioxide Transport in the Body

    • Carbon dioxide is transported in the blood in three ways:
      • Dissolved carbon dioxide (7%)
      • Carbamino compounds (25%)
      • Bicarbonate ions (70%)

    Hypoxia and Hypoxemia

    • Hypoxia: insufficient oxygen in the tissues
    • Hypoxemia: insufficient oxygen in the blood
    • Causes of hypoxia can be classified into four groups:
      • Hypoxic hypoxia
      • Anemic hypoxia
      • Hypoperfusion hypoxia
      • Histotoxic hypoxia

    Control of Respiration

    • Breathing is involuntary and controlled by specific regions within the brainstem
    • The control of breathing is complex due to the anatomical location and the complex organization of neural networks

    Pulmonary Gas Exchange and Transport of Oxygen and Carbon Dioxide

    • Exchange I: Atmosphere to Lung (Ventilation and Alveolar Ventilation)
    • Exchange II: Lung to Blood (Pulmonary Gas Exchange and Oxygen and Carbon Dioxide transport in the blood)
    • Exchange III: Blood to Cells (Cellular Respiration via Mitochondria)
    • The ventilation-perfusion relationship is the ratio of alveolar ventilation and blood perfusion rates of the lung
    • Ideally, each alveolus in the lungs would receive the same amount of ventilation and pulmonary capillary blood flow (perfusion)

    Ventilation-Perfusion Relationship of the Lungs

    • Regional differences in lung ventilation are due to variations in pleural pressures (and transpulmonary pressures) that exist between the apex and base of the lungs

    • Alveoli in upper lung have a higher transpulmonary pressure, are near-maximally inflated and relatively noncompliant

    • Alveoli in lower lung are smaller and have a lower transpulmonary pressure, are more compliant and undergo greater expansion during inspiration### Pulmonary Gas Exchange

    • Blood is diverted from poorly ventilated alveoli to better ventilated ones through hypoxic pulmonary vasoconstriction to maintain a matched V/Q in the lungs.

    • Pulmonary gas exchange occurs at the alveolar-capillary membrane, which forms the blood-gas interface.

    • Henry's Law states that the quantity of a slightly soluble gas that dissolves in a given mass of liquid at a particular temperature is proportional to the partial pressure of that gas.

    • Fick's First Law of Diffusion states that the diffusion rate increases when the surface area, the ionic concentration gradient, and permeability increase.

    • Pulmonary diffusing capacity measures the ability of the alveolar-capillary membranes to conduct gases.

    Oxygen Transport in the Body

    • O2 in the blood is transported in two ways: physically dissolved in the blood and chemically bound to hemoglobin (Hb).
    • The physically dissolved O2 is very low, with a solubility coefficient of 0.003mL/100mL of blood at a normal body temperature.
    • Hemoglobin (Hb) is a complex molecule with a tetrameric structure consisting of 4 polypeptide chains (globin), each of which contains a protoporphyrin (heme) group that can bind one molecule of oxygen.
    • Each Hb molecule can bind 4 molecules of O2.
    • Normal adult Hb (HbA) consists of two α-chains and two β-chains.
    • Abnormal variants of Hb, such as HbS, can cause sickle cell disease.

    Oxygen Loading (Content) in the Lungs

    • The oxyhemoglobin dissociation curve relates the percent of O2 saturation to the partial pressure of oxygen (PO2).
    • The curve has a sigmoidal shape, plotting all 4 reactions of oxygen binding to the Hb molecule.
    • At a normal arterial P02 of 100mmHg, the Hb saturation is 98%.
    • Percent saturation is calculated by dividing the content of oxygen in the blood by the oxygen carrying capacity of Hb.

    Alterations in the Oxyhemoglobin Dissociation Curve

    • Shifts in the oxyhemoglobin dissociation curve can be best described by the P50, which is the PO2 at which 50% of the Hb present in the blood is deoxyhemoglobin and the other 50% is oxyhemoglobin.
    • Alterations in temperature, pH, PCO2, and 2,3-DPG can cause shifts in the oxyhemoglobin dissociation curves.
    • The Bohr effect explains why cells oxygen release or red blood cells unload oxygen in tissues, with higher CO2 values leading to more oxygen release.

    Carbon Dioxide Transport in the Body

    • Carbon dioxide is transported in the blood in three ways: dissolved carbon dioxide (7%), carbamino compounds (25%), and bicarbonate ions (70%).

    Respiratory Stress: Hypoxia and Hypoxemia

    • Hypoxia and hypoxemia are types of respiratory stress, with hypoxemia referring to insufficient oxygen in the blood and hypoxia referring to insufficient oxygen in the tissues.
    • The causes of hypoxia can be classified into four groups: hypoxic hypoxia, anemic hypoxia, hypoperfusion hypoxia, and histotoxic hypoxia.

    Control of Respiration

    • Breathing is involuntary and controlled by specific regions within the brainstem.
    • The control of breathing is complex due to the anatomical location and complex organization of neural networks.

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    Description

    Test your knowledge on calculating blood oxygen capacity based on the amount of oxygen bound to hemoglobin and physically dissolved oxygen at a specific partial pressure of oxygen. Explore concepts such as oxygen loading in the lungs and oxygen transport in the body.

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