Respiratory System: Gas Exchange & Transport
51 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What effect does a decrease in blood pH have on the O2 binding affinity of hemoglobin?

  • Has no effect on O2 binding affinity
  • Increases O2 binding affinity
  • Increases CO2 binding affinity
  • Decreases O2 binding affinity (correct)

    • What is the physiological significance of the Bohr effect in metabolically active tissues?

  • It enhances O2 release in active tissues. (correct)
  • It increases O2 uptake in the lungs.
  • It stabilizes hemoglobin structure.
  • It reduces O2 release in all tissues.

    • How does an increase in blood temperature affect hemoglobin's O2 binding affinity?

  • Causes hemoglobin to become rigid
  • Increases O2 binding affinity
  • Decreases O2 binding affinity (correct)
  • Has no effect on O2 binding affinity

    • What is an expected result of a rightward shift in the oxy-Hb dissociation curve?

    <p>Decreased O2 affinity (D)</p> Signup and view all the answers

    What conditions are typically associated with a leftward shift in the oxy-Hb dissociation curve?

    <p>Increased pH levels (C)</p> Signup and view all the answers

    What biochemical factors contribute to the Bohr effect?

    <p>Increase in carbon dioxide levels (D)</p> Signup and view all the answers

    What happens to the O2 extraction from hemoglobin as blood pH decreases?

    <p>O2 extraction increases (D)</p> Signup and view all the answers

    What is considered the normal body temperature related to hemoglobin function?

    <p>37°C (A)</p> Signup and view all the answers

    What process primarily facilitates the exchange of O2 and CO2 across the alveolar-capillary interface?

    <p>Simple diffusion (C)</p> Signup and view all the answers

    Which factor does NOT directly influence the rate of gas diffusion according to Fick's Law of Diffusion?

    <p>Blood pH level (D)</p> Signup and view all the answers

    Why does oxygenated blood return to the left side of the heart?

    <p>To be pumped to the systemic circulation (D)</p> Signup and view all the answers

    What best describes the flow of O2 and CO2 in tissue capillary beds?

    <p>O2 flows into tissues while CO2 enters the capillaries (A)</p> Signup and view all the answers

    What primarily drives the movement of gases during gas exchange?

    <p>Pressure gradient (A)</p> Signup and view all the answers

    What role does gas solubility play in the transport of gases in the blood?

    <p>It affects the ease with which a gas dissolves in blood plasma. (D)</p> Signup and view all the answers

    What happens to deoxygenated blood after it returns to the right side of the heart?

    <p>It is pumped to the lungs for oxygenation. (B)</p> Signup and view all the answers

    According to Fick's Law of Diffusion, how does the concentration gradient affect the diffusion rate?

    <p>It is directly proportional to the diffusion rate. (B)</p> Signup and view all the answers

    What happens to the O2 binding affinity of hemoglobin (Hb) when the temperature of blood increases in metabolically active tissues?

    <p>It decreases, facilitating O2 release. (D)</p> Signup and view all the answers

    What is the normal partial pressure of carbon dioxide (PCO2) in arterial blood?

    <p>40 mmHg (A)</p> Signup and view all the answers

    How does an increase in PCO2 affect the O2 binding affinity of Hb?

    <p>It decreases O2 binding affinity. (B)</p> Signup and view all the answers

    What effect does a decrease in blood temperature have on Hb's affinity for O2?

    <p>It increases O2 binding affinity. (A)</p> Signup and view all the answers

    What physiological change occurs as blood passes through capillaries in metabolically active tissues?

    <p>PCO2 increases and O2 binding affinity decreases. (A)</p> Signup and view all the answers

    What shift occurs in the oxy-Hb dissociation curve when PCO2 is below normal levels?

    <p>Leftward shift indicating increased affinity. (B)</p> Signup and view all the answers

    How does CO2 produced during metabolism affect O2 delivery to tissues?

    <p>It facilitates O2 release from Hb. (A)</p> Signup and view all the answers

    As blood passes through the lung capillaries, what change occurs to the PCO2 and how does it affect O2 affinity?

    <p>PCO2 decreases, causing increased O2 affinity. (B)</p> Signup and view all the answers

    What do peripheral chemoreceptors primarily monitor in the arterial blood?

    <p>pH and PCO2 (D)</p> Signup and view all the answers

    Where are central chemoreceptors located?

    <p>On the surface of the medulla oblongata (D)</p> Signup and view all the answers

    What happens when PCO2 decreases in the arterial blood?

    <p>CO2 removal from the blood increases (D)</p> Signup and view all the answers

    What primarily stimulates the peripheral chemoreceptors?

    <p>Decreased pH and increased PCO2 (C)</p> Signup and view all the answers

    What is the response of the medullary respiratory centers when PCO2 rises?

    <p>Decrease depth and rate of breathing (D)</p> Signup and view all the answers

    What structures primarily regulate the inspiratory muscles during breathing?

    <p>Dorsal respiratory group (DRG) (C)</p> Signup and view all the answers

    During normal quiet breathing, which part of the respiratory centers is primarily inactive?

    <p>Ventral respiratory group (VRG) (D)</p> Signup and view all the answers

    Which receptors provide input to the medullary respiratory centers to help maintain blood gas homeostasis?

    <p>Chemoreceptors (C)</p> Signup and view all the answers

    What is the role of the pontine respiratory centers?

    <p>Modulate the medullary respiratory centers (D)</p> Signup and view all the answers

    What primarily causes expiration during normal quiet breathing?

    <p>Elastic recoil of muscles and lung tissue (D)</p> Signup and view all the answers

    Which muscle is NOT considered an inspiratory muscle during normal quiet breathing?

    <p>Internal intercostal muscles (B)</p> Signup and view all the answers

    Which of the following best describes the state of breathing during normal quiet breathing?

    <p>Subconscious and regulated by chemoreceptors (C)</p> Signup and view all the answers

    What is the primary function of the respiratory pacemaker neurons in the VRG?

    <p>Set the rhythmic pattern of breathing (B)</p> Signup and view all the answers

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

    <p>Bicarbonate ions (HCO3–) (B), CO2 bound to hemoglobin (Hb CO2) (C)</p> Signup and view all the answers

    What process allows bicarbonate ions to be transported out of red blood cells?

    <p>Chloride shift (A)</p> Signup and view all the answers

    Which of the following represents the cellular reaction occurring in red blood cells involving carbon dioxide?

    <p>CO2 + Hb ↔ Hb CO2 (C), CO2 + H2O ↔ HCO3– + H+ (D)</p> Signup and view all the answers

    What occurs when carbon dioxide diffuses into the alveoli from the blood?

    <p>It is expelled during exhalation. (D)</p> Signup and view all the answers

    How are H+ ions related to hemoglobin in the transport of carbon dioxide?

    <p>They bind to the globin portion of hemoglobin. (D)</p> Signup and view all the answers

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

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

    What happens to hemoglobin in the lungs regarding carbon dioxide?

    <p>It converts bicarbonate back to carbon dioxide. (A), It releases carbon dioxide. (C)</p> Signup and view all the answers

    Which of the following is true concerning the transport of CO2 in tissues?

    <p>Most is converted to bicarbonate within red blood cells. (D)</p> Signup and view all the answers

    What is the primary role of carbonic anhydrase (CA) in red blood cells?

    <p>Catalyze the formation of carbonic acid (B)</p> Signup and view all the answers

    What is the significance of the chloride shift in CO2 transport?

    <p>It facilitates the exchange of ions during CO2 transport. (D)</p> Signup and view all the answers

    What is the first step of carbon dioxide transport from tissues to lungs?

    <p>Release from cells (B)</p> Signup and view all the answers

    At which location does carbon dioxide get converted back from bicarbonate for expiration?

    <p>In the alveoli (A)</p> Signup and view all the answers

    What effect does increased carbon dioxide in the blood typically have?

    <p>Decreased pH levels (A)</p> Signup and view all the answers

    What is the fate of hydrogen ions produced in red blood cells during CO2 transport?

    <p>They bind to hemoglobin. (C)</p> Signup and view all the answers

    Flashcards

    Gas Exchange

    The movement of oxygen (O2) and carbon dioxide (CO2) across the alveolar-capillary interface and capillary-tissue interface, occurring due to simple diffusion.

    Alveolar-Capillary Interface

    The thin membrane separating the air in the alveoli and the blood in the capillaries where gas exchange occurs.

    Pressure Gradient

    The difference in pressure between two areas of a gas, driving the movement of the gas from high to low pressure.

    Fick's Law of Diffusion

    A law stating that the rate of diffusion of a gas is directly proportional to the surface area for gas exchange, membrane permeability, and concentration gradient, and inversely proportional to membrane thickness.

    Signup and view all the flashcards

    Gas Solubility

    The ease with which a gas dissolves in a liquid, like blood plasma, influencing its movement across membranes.

    Signup and view all the flashcards

    Oxygenated blood

    Blood that has taken up oxygen in the lungs.

    Signup and view all the flashcards

    Deoxygenated blood

    Blood that has released oxygen to the tissues.

    Signup and view all the flashcards

    Diffusion Rate

    The speed at which gases move across a membrane due to pressure difference. It's affected by factors outlined in Fick's Law.

    Signup and view all the flashcards

    Bohr Effect

    The relationship between pH and oxygen binding affinity of hemoglobin.

    Signup and view all the flashcards

    Lower blood pH

    Decreased oxygen binding to hemoglobin, leading to easier oxygen release.

    Signup and view all the flashcards

    Higher blood pH

    Increased oxygen binding to hemoglobin, oxygen held onto more tightly.

    Signup and view all the flashcards

    Oxy-Hb dissociation curve shift (acidic)

    Shifting to the right when blood pH decreases (becomes more acidic).

    Signup and view all the flashcards

    Oxy-Hb dissociation curve shift (basic)

    Shifting to the left when blood pH increases (becomes more basic).

    Signup and view all the flashcards

    Increased blood temperature

    Decreased oxygen binding affinity, causing a rightward shift in the oxy-hemoglobin dissociation curve.

    Signup and view all the flashcards

    Decreased blood temperature

    Increased oxygen binding affinity, causing a leftward shift in the oxy-hemoglobin dissociation curve.

    Signup and view all the flashcards

    Effect of tissue metabolism on blood pH

    Increased tissue activity releases H+, lowering blood pH in local capillaries.

    Signup and view all the flashcards

    Temperature and O2 Binding

    The relationship between temperature and the oxygen-binding affinity of hemoglobin (Hb). As temperature rises, Hb's affinity for O2 decreases, releasing more oxygen to tissues. Conversely, cooling increases Hb's affinity, promoting O2 uptake in the lungs.

    Signup and view all the flashcards

    PCO2 and O2 Binding

    The inverse relationship between carbon dioxide (CO2) levels and hemoglobin's (Hb) affinity for oxygen. Increased CO2 in the blood reduces Hb's affinity for O2, aiding O2 release at active tissues. Conversely, lower CO2 increases Hb's affinity, promoting O2 uptake in the lungs.

    Signup and view all the flashcards

    Peripheral Chemoreceptors

    Specialized sensory cells located in the carotid and aortic bodies that monitor pH (H+ concentration), PCO2, and PO2 in the arterial blood. They are highly sensitive to pH and PCO2 but somewhat less sensitive to PO2.

    Signup and view all the flashcards

    Central Chemoreceptors

    These receptors are located on the surface of the medulla oblongata and monitor H+ concentration and PCO2 in the cerebrospinal fluid (CSF).

    Signup and view all the flashcards

    Increase in PCO2 or decrease in pH

    This triggers an increase in the signal rate from chemoreceptors to the medullary respiratory centers, leading to an increase in lung ventilation (faster and deeper breathing).

    Signup and view all the flashcards

    Decrease in PCO2 or increase in pH

    This leads to a decrease in the signal rate from the chemoreceptors to the medullary respiratory centers, causing a decrease in lung ventilation (slower and shallower breathing).

    Signup and view all the flashcards

    Homeostatic Regulation of Blood Gases

    A feedback loop involving chemoreceptors and the respiratory system that adjusts lung ventilation to maintain normal levels of PCO2, pH, and PO2 in the blood.

    Signup and view all the flashcards

    Respiratory Rhythm

    The regular pattern of breathing controlled by specialized neural centers in the brain.

    Signup and view all the flashcards

    Medulla Oblongata

    A part of the brainstem vital for controlling involuntary functions like breathing.

    Signup and view all the flashcards

    Chemoreceptors

    Specialized sensory cells that detect changes in blood gas levels like oxygen and carbon dioxide.

    Signup and view all the flashcards

    Dorsal Respiratory Group (DRG)

    A region in the medulla that primarily controls the inspiratory muscles, helping you to breathe in.

    Signup and view all the flashcards

    Ventral Respiratory Group (VRG)

    A region in the medulla that primarily controls the expiratory muscles, helping you to breathe out.

    Signup and view all the flashcards

    Respiratory Pacemaker Neurons

    Specialized neurons in the VRG that generate the rhythmic signals for breathing in the resting state.

    Signup and view all the flashcards

    Pontine Respiratory Centers

    Brain regions in the pons that receive inputs from higher brain centers and modulate the activity of the medullary centers.

    Signup and view all the flashcards

    Voluntary Control of Breathing

    The ability to consciously alter breathing rate and depth, typically triggered by emotions or external stimuli.

    Signup and view all the flashcards

    CO2 Transport

    The process of moving carbon dioxide (CO2) from the tissues where it's produced to the lungs where it's exhaled.

    Signup and view all the flashcards

    Venous Blood

    Blood that carries oxygen-depleted (deoxygenated) blood and high levels of CO2 back to the heart.

    Signup and view all the flashcards

    Dissolved CO2

    CO2 molecules directly dissolved in the blood plasma, representing around 7% of total CO2 transport.

    Signup and view all the flashcards

    CO2 bound to Hb

    CO2 binds to hemoglobin (Hb) inside red blood cells, accounting for about 23% of CO2 transport.

    Signup and view all the flashcards

    Bicarbonate Ion (HCO3-)

    The most significant way CO2 is transported, making up 70% of the total. CO2 and H2O form carbonic acid (H2CO3) which then dissociates into H+ and HCO3- ions.

    Signup and view all the flashcards

    Chloride Shift

    The exchange of bicarbonate ions (HCO3-) for chloride ions (Cl-) across the membrane of red blood cells.

    Signup and view all the flashcards

    Hb H

    Hemoglobin carrying H+ ions. When CO2 forms H2CO3, the released H+ binds to hemoglobin.

    Signup and view all the flashcards

    Pulmonary Circulation

    The blood circuit between the heart and the lungs. Blood carries CO2 to the lungs for release.

    Signup and view all the flashcards

    CO2 Diffusion from RBC

    In the lungs, CO2 detaches from hemoglobin and diffuses from red blood cells into the alveolar air.

    Signup and view all the flashcards

    Chloride Shift Reversal

    In the lungs, the bicarbonate ions that were transported into the plasma move back into the RBC in exchange for chloride ions.

    Signup and view all the flashcards

    H+ Removal from Hb

    In the lungs, H+ ions detach from hemoglobin, which is the reverse of what occurred at the tissues.

    Signup and view all the flashcards

    H2CO3 Formation

    In the lungs, H+ ions and bicarbonate ions recombine to form carbonic acid (H2CO3).

    Signup and view all the flashcards

    CA Converted H2CO3

    Carbonic anhydrase (CA) within red blood cells converts carbonic acid (H2CO3) back into CO2 and H2O.

    Signup and view all the flashcards

    CO2 Pressure Gradient

    The difference in CO2 partial pressure between the blood and the alveolar air, driving CO2 diffusion.

    Signup and view all the flashcards

    Lung Ventilation

    The process of breathing, involving inhalation and exhalation, which is essential for oxygen intake and CO2 expulsion.

    Signup and view all the flashcards

    Study Notes

    Respiratory System: Gas Exchange and Transport

    • Gas exchange occurs in the alveoli of the lungs, where gases are exchanged with the blood across the alveolar-capillary interface.
    • Air is brought into the alveoli, and oxygen enters the blood.
    • Carbon dioxide leaves the blood and enters the alveoli.
    • Oxygenated blood is returned to the heart and pumped to the body.
    • Deoxygenated blood returns to the heart and is pumped back to the lungs.

    Gas Exchange

    • Movement of oxygen and carbon dioxide across interfaces results from simple diffusion.
    • The driving force for gas movement is the pressure gradient.
    • Gases move from areas of higher pressure to lower pressure.
    • The rate of diffusion is affected by factors such as surface area, membrane permeability, and membrane thickness; the concentration gradient is the primary determinant.

    Gas Solubility

    • The solubility of a gas in a liquid affects its movement between air and blood.
    • Gases with higher solubility dissolve readily at lower pressures.
    • CO2 is more soluble than O2, which is why animals evolved oxygen-binding proteins (like hemoglobin)
    • These proteins facilitate the transport of a gas that has low solubility, such as oxygen, in the blood.

    Gas Exchange at the Alveoli and Cells

    • Oxygen moves from the alveoli into the blood (high Po2 in alveoli, low Po2 in blood); carbon dioxide moves from the blood to the alveoli (high Pco2 in blood, low Pco2 in alveoli).
    • At the tissues, oxygen moves from blood (high Po2) to tissues (low Po2); carbon dioxide moves from tissues (high Pco2) to blood (low Pco2).

    Gas Transport: Transport of O2 in Blood

    • Oxygen is transported in the blood in two ways:
      • Dissolved in the plasma (a small percentage).
      • Bound to hemoglobin within red blood cells (a larger percentage).
    • Hemoglobin molecules can bind up to four oxygen molecules.

    Hemoglobin Binding

    • The amount of oxygen bound to hemoglobin depends on the partial pressure of oxygen (Po2) in the blood.
    • As Po2 increases, more oxygen binds to hemoglobin until all binding sites are occupied.
    • Oxygen saturation is expressed as a percentage.

    Oxygen-Hemoglobin Dissociation Curve

    • The oxygen-hemoglobin dissociation curve shows the relationship between Po2 and the percent oxygen saturation of hemoglobin.
    • Factors like temperature and pH affect the curve position, which affects the release of oxygen from hemoglobin in the tissues.

    Gas Transport: Factors Affecting O2 Binding Affinity of Hemoglobin

    • Factors like pH, temperature, and carbon dioxide (PCO2) in the blood affect the oxygen-binding affinity of hemoglobin.
    • Changes in these factors cause shifts in the oxygen-hemoglobin dissociation curve.

    Physiological Significance of Changes in Oxygen-Binding Affinity

    • When tissues increase their metabolic rate, they release H+, which lowers the pH and decreases the oxygen-binding affinity of hemoglobin, and more oxygen is released from hemoglobin to tissues.
    • The temperature of the blood also influences oxygen binding.

    Gas Transport: Transport of CO2 in Blood

    • Carbon dioxide is transported ways:
    • Dissolved in plasma (a small amount).
    • Chemically bonded to hemoglobin (a small amount).
    • As bicarbonate ion (a major portion).
    • The enzyme carbonic anhydrase plays a crucial role in converting CO2 into bicarbonate ions.

    Regulation of Lung Ventilation

    • The rhythm of breathing is controlled by neural centers in the central nervous system (CNS).
    • Normal quiet breathing is subconscious (uncontrolled).
    • Rate and depth of breathing can be adjusted based on chemoreceptors' input to the respiratory centers.
    • Chemoreceptors monitor blood pH and gas levels and adjust the rate and depth of breathing accordingly.

    Regulation of Lung Ventilation: Chemoreceptors

    • Peripheral chemoreceptors monitor arterial blood pH, PCO2, and PO2.
    • Central chemoreceptors monitor cerebrospinal fluid pH and PCO2, and these receptors are more sensitive to carbon dioxide.

    Regulation of Lung Ventilation: Homeostatic Regulation

    • A feedback loop controls ventilation (the act of breathing) to keep blood gases (PCO2 and pH) in balance.
    • Changes in blood gases (PCO2) stimulate adjustments in breathing rate and depth to maintain homeostasis.

    Gas Transport: 2,3 DPG and O2 Binding Affinity of Hb

    • 2,3-DPG is an organic phosphate that reduces hemoglobin's affinity for oxygen.
    • High 2,3-DPG levels are often associated with conditions like altitude sickness.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Respiratory System Continued spr 2k24 PDF

    Description

    Explore the intricate processes of gas exchange and transport within the respiratory system. This quiz covers key concepts such as the role of alveoli, diffusion of gases, and factors affecting gas solubility. Test your knowledge on how oxygen and carbon dioxide are transported throughout the body.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser