p.15
Oxygen-Hemoglobin Dissociation Curve
What is the Bohr effect?
The shift in the HbO2 curve resulting from a change in pH.
p.4
Gas Solubility and Transport
What happens when a gas is less soluble?
Very few gas molecules dissolve in the liquid even at a high partial pressure.
p.7
Factors Affecting Gas Exchange
How does P O2 in the air change with altitude?
P O2 decreases along with atmospheric pressure (P atm).
p.18
Carbon Dioxide Transport in Blood
What is the compound formed when carbon dioxide binds to hemoglobin?
Carbaminohemoglobin (Hb·CO2)
p.15
Factors Affecting Gas Exchange
What factors can affect the ability of hemoglobin (Hb) to bind oxygen?
Factors that change the conformation of Hb, such as plasma pH.
p.17
Oxygen Transport Mechanisms
How does fetal hemoglobin (FHb) facilitate oxygen transfer in the placenta?
At any given placental PO2, fetal hemoglobin (FHb) picks up oxygen released by maternal hemoglobin (HbA).
p.12
Oxygen and Carbon Dioxide Diffusion
What causes the plasma PO2 to decrease when arterial blood reaches the tissue?
The diffusion of dissolved O2 out of the systemic capillaries into cells.
p.7
Factors Affecting Gas Exchange
What happens if the alveolar P O2 can’t reach 100 mm Hg?
It affects arterial P O2 and reduces oxygen delivery to cells, causing symptoms like headache, dizziness, and nausea.
p.16
Factors Affecting Gas Exchange
How does an increase in temperature affect oxygen-hemoglobin binding?
An increase in temperature decreases the affinity of hemoglobin to oxygen, leading to more oxygen being unloaded to the tissue.
p.5
Oxygen and Carbon Dioxide Diffusion
What happens to the partial pressure of oxygen (P O2) in the pulmonary vein leaving the lung?
P O2 in the pulmonary vein leaving the lung equals P O2 in the alveoli.
p.11
Oxygen Transport Mechanisms
What does the binding and release of oxygen in hemoglobin depend on?
The partial pressure of oxygen (P O2) in the plasma surrounding the red blood cells (RBC).
p.17
Oxygen Transport Mechanisms
What happens to oxygen released by maternal hemoglobin (HbA) in the placenta?
Oxygen released by maternal hemoglobin (HbA) is picked up by fetal hemoglobin (FHb).
p.12
Oxygen Transport Mechanisms
Describe the sequence of oxygen movement from hemoglobin to cells.
Oxygen is released from Hb to plasma, then from plasma to cells.
p.8
Overview of Gas Exchange
What is the function of the alveolar epithelium in gas exchange?
It facilitates the diffusion of oxygen from the alveolar air space into the blood.
p.5
Oxygen and Carbon Dioxide Diffusion
Why is the intracellular P O2 in peripheral tissues approximately 40 mm Hg?
Because peripheral tissues keep using oxygen for oxidative phosphorylation.
p.14
Oxygen-Hemoglobin Dissociation Curve
How much oxygen do cells use at rest in the oxygen transport system?
Cells use up only ¼ of the oxygen.
p.3
Diffusion and Fick's Law
What defines equilibrium in the context of gas exchange between air and water?
Equilibrium is when the movement of air molecules from the air into the water equals the movement of air molecules from the water back into the air.
p.17
Hemoglobin Structure and Function
How does the structure of fetal hemoglobin (FHb) differ from maternal hemoglobin (HbA)?
Fetal hemoglobin (FHb) has two γ chains, which enhance its ability to bind oxygen in the low-oxygen environment of the placenta.
p.18
Carbon Dioxide Transport in Blood
What is the chemical reaction catalyzed by carbonic anhydrase in red blood cells?
CO2 + H2O → H2CO3 → H+ + HCO3-
p.12
Oxygen and Carbon Dioxide Diffusion
What happens to dissolved O2 when arterial blood reaches the tissue?
Dissolved O2 diffuses out of systemic capillaries into cells.
p.1
Overview of Gas Exchange
Where does gas exchange occur in the respiratory system?
At pulmonary and systemic capillaries.
p.15
Factors Affecting Gas Exchange
What happens to H+ concentration and pH during exercise and anaerobic metabolism in muscle fibers?
H+ concentration increases, causing pH to decrease.
p.1
Oxygen and Carbon Dioxide Diffusion
What is the role of pulmonary arteries in gas exchange?
Pulmonary arteries carry deoxygenated blood from the right ventricle to the lungs for oxygenation.
p.9
Oxygen Transport Mechanisms
How does hemoglobin increase oxygen transport in the blood?
Hemoglobin binds to oxygen, significantly increasing the oxygen-carrying capacity of the blood.
p.11
Oxygen Transport Mechanisms
Describe the pathway of oxygen from the alveoli to hemoglobin.
Oxygen moves from the alveoli to the plasma, then to red blood cells, and finally binds onto hemoglobin.
p.8
Oxygen Transport Mechanisms
What is the role of red blood cells in oxygen transport?
Red blood cells transport oxygen bound to hemoglobin to cells for use in cellular respiration.
p.1
Oxygen and Carbon Dioxide Diffusion
What is the role of systemic veins in gas exchange?
Systemic veins carry deoxygenated blood from the tissues back to the right atrium of the heart.
p.16
Factors Affecting Gas Exchange
What is the carbamino effect?
The carbamino effect is when CO2 reacts with hemoglobin to form Hb·CO2, altering the structure of hemoglobin and decreasing its affinity for oxygen.
p.16
Factors Affecting Gas Exchange
What is the result of hemoglobin's decreased affinity for oxygen due to increased temperature or P CO2?
More oxygen is unloaded to the tissue.
p.11
Oxygen Transport Mechanisms
What facilitates the binding of oxygen with hemoglobin?
High partial pressure of oxygen (P O2).
p.1
Overview of Gas Exchange
What are the two main components of gas exchange and transport in the respiratory system?
Exchange of gases between compartments (diffusion across cell membranes) and transport of gases in the blood.
p.1
Oxygen and Carbon Dioxide Diffusion
What is the role of pulmonary veins in gas exchange?
Pulmonary veins carry oxygenated blood from the lungs to the left atrium of the heart.
p.4
Gas Solubility and Transport
Which gas is more soluble in water, CO2 or O2?
CO2 is more soluble than oxygen in water.
p.14
Oxygen-Hemoglobin Dissociation Curve
What is the physiological significance of the oxygen-hemoglobin dissociation curve?
It shows how hemoglobin saturation with oxygen varies with changes in partial pressure of oxygen (P O2).
p.10
Hemoglobin Structure and Function
What is the composition of most adult hemoglobin (HbA)?
Most adult hemoglobin (HbA) has two α chains and two β chains.
p.3
Gas Solubility and Transport
Why are the concentrations of oxygen in air and water not equal at equilibrium?
Because oxygen has low solubility in water, meaning concentrations are not equal even if PO2 is the same.
p.2
Diffusion and Fick's Law
What is Fick's law of diffusion?
Diffusion rate is proportional to the surface area, concentration gradient, and membrane permeability, and inversely proportional to membrane thickness.
p.11
Oxygen Transport Mechanisms
What facilitates the release of oxygen from hemoglobin?
Low partial pressure of oxygen (P O2).
p.4
Gas Solubility and Transport
What is the concentration of oxygen in water at 100 mm Hg?
5.20 mmol/L or 0.15 mmol/L depending on the context.
p.13
Oxygen-Hemoglobin Dissociation Curve
What does the oxygen-hemoglobin dissociation curve describe?
The physical relationship between partial pressure of oxygen (P O2) and hemoglobin (Hb) saturation.
p.13
Oxygen-Hemoglobin Dissociation Curve
How does the % saturation of hemoglobin change with increasing P O2?
The % saturation of hemoglobin increases as the P O2 increases.
p.3
Overview of Gas Exchange
In what forms can gas molecules exist?
Gas molecules can exist in gaseous form or be dissolved in liquid.
p.3
Oxygen and Carbon Dioxide Diffusion
What is the initial state of oxygen in a solution with no O2?
The initial state has no O2 in the solution.
p.17
Hemoglobin Structure and Function
Why is fetal hemoglobin (FHb) more efficient at binding oxygen in the placenta compared to maternal hemoglobin (HbA)?
The two γ chains in fetal hemoglobin (FHb) enhance its ability to bind oxygen in the low-oxygen environment of the placenta.
p.4
Gas Solubility and Transport
What are the three factors that the movement of gas from air to liquid is directly proportional to?
Pressure gradient, temperature (can be ignored as body temperature is relatively constant), and solubility of the gas.
p.8
Oxygen Transport Mechanisms
What are the two main ways oxygen is transported in the blood?
Dissolved in plasma and bound to hemoglobin.
p.4
Gas Solubility and Transport
What does the solubility of a gas refer to?
The ease with which a gas dissolves in a liquid.
p.15
Oxygen-Hemoglobin Dissociation Curve
How does a decrease in plasma pH from 7.4 to 7.2 affect hemoglobin saturation at a PO2 of 40 mm Hg?
The % saturation of Hb decreases from 75% to approximately 60%, releasing 13% more oxygen at pH 7.2 than at pH 7.4.
p.4
Gas Solubility and Transport
What happens when a gas is highly soluble?
A large amount of gas molecules go into solution even at a low gas pressure.
p.2
Diffusion and Fick's Law
Which factors are quite constant in our respiratory tissue according to Fick's law?
Surface area for gas exchange, membrane permeability, membrane thickness, and diffusion distance.
p.15
Oxygen-Hemoglobin Dissociation Curve
What is the effect of increased H+ concentration on the HbO2 curve?
The HbO2 curve shifts to the right, resulting in more oxygen being released from Hb to the tissue.
p.5
Oxygen and Carbon Dioxide Diffusion
How does oxygen move from the alveoli into the capillaries?
Oxygen moves down its partial pressure gradient from the alveoli into the capillaries.
p.7
Factors Affecting Gas Exchange
What are the P atm and P O2 values at sea level?
P atm = 760 mm Hg, P O2 = 160 mm Hg.
p.7
Factors Affecting Gas Exchange
What are the P atm and P O2 values in Denver (1609m above sea level)?
P atm = 628 mm Hg, P O2 = 132 mm Hg.
p.5
Oxygen and Carbon Dioxide Diffusion
How does oxygen diffuse from the plasma into cells?
Oxygen diffuses down its partial pressure gradient from the plasma into cells until venous blood has the same P O2 as the cells.
p.13
Oxygen-Hemoglobin Dissociation Curve
What occurs to hemoglobin saturation when P O2 falls below 60 mm Hg?
There is a significant reduction in the % saturation of hemoglobin, reflected by a steep slope on the curve.
p.10
Hemoglobin Structure and Function
What does each subunit of hemoglobin contain?
Each subunit contains a globin and an iron-containing heme group.
p.10
Hemoglobin Structure and Function
Is the binding of oxygen to hemoglobin a reversible process?
Yes, the binding of oxygen is a reversible process.
p.3
Diffusion and Fick's Law
Does equilibrium mean equal concentration of air molecules in air and water?
No, equilibrium does not mean equal concentration of air molecules in air and water.
p.6
Carbon Dioxide Transport in Blood
How does CO2 move during gas exchange in the tissues?
CO2 moves down its partial pressure gradient from the tissue into the capillaries until systemic venous blood reaches a P CO2 of 46 mm Hg.
p.12
Oxygen-Hemoglobin Dissociation Curve
How does the decrease in plasma PO2 affect the oxygen-Hb binding reaction?
It disturbs the equilibrium of the oxygen-Hb binding reaction, leading to the release of oxygen from Hb to plasma.
p.11
Oxygen Transport Mechanisms
What causes more oxygen to diffuse from the alveoli into the plasma?
The removal of dissolved oxygen in plasma, which decreases plasma P O2.
p.4
Gas Solubility and Transport
What is the concentration of carbon dioxide in water at 100 mm Hg?
5.20 mmol/L or 3.00 mmol/L depending on the context.
p.1
Oxygen and Carbon Dioxide Diffusion
What is the function of the right ventricle in the respiratory system?
The right ventricle pumps deoxygenated blood into the pulmonary arteries for oxygenation in the lungs.
p.13
Oxygen-Hemoglobin Dissociation Curve
What happens to hemoglobin saturation if alveolar P O2 falls to 60 mm Hg or higher?
Hemoglobin still reaches more than 90% saturation.
p.3
Diffusion and Fick's Law
What happens when a gas is placed in contact with water?
There is a pressure gradient, causing gas molecules to move from one phase to the other until equilibrium is reached.
p.3
Oxygen and Carbon Dioxide Diffusion
What happens to oxygen when it dissolves in water?
Oxygen dissolves in water until the PO2 in air and water is equal at equilibrium.
p.6
Carbon Dioxide Transport in Blood
What happens to CO2 at the pulmonary capillaries?
CO2 diffuses down its partial pressure gradient from the venous capillaries to the alveoli.
p.19
Carbon Dioxide Transport in Blood
What is the form of CO2 when it binds with hemoglobin?
Hb•CO2 (Carbaminohemoglobin)
p.11
Oxygen Transport Mechanisms
What happens in the pulmonary capillaries when alveolar P O2 is greater than plasma P O2?
Oxygen dissolved in plasma diffuses into red blood cells where it binds to hemoglobin.
p.8
Overview of Gas Exchange
Where does gas exchange primarily occur in the respiratory system?
Across the alveolar membrane and capillary endothelium.
p.8
Overview of Gas Exchange
What is the role of surfactant in the alveoli?
Surfactant reduces surface tension, preventing alveolar collapse and aiding in gas exchange.
p.10
Hemoglobin Structure and Function
What is the composition of fetal hemoglobin (HbF)?
Fetal hemoglobin (HbF) has two α chains and two γ chains.
p.1
Oxygen and Carbon Dioxide Diffusion
What is the role of systemic arteries in gas exchange?
Systemic arteries carry oxygenated blood from the left ventricle to the tissues of the body.
p.16
Factors Affecting Gas Exchange
What happens to hemoglobin's affinity for oxygen when P CO2 increases?
An increase in P CO2 decreases hemoglobin's affinity for oxygen due to the carbamino effect.
p.13
Oxygen-Hemoglobin Dissociation Curve
What percentage of hemoglobin is bound to oxygen at normal alveolar and arterial P O2?
98% of hemoglobin is bound to oxygen.
p.10
Hemoglobin Structure and Function
What are the common forms of globin protein chains in hemoglobin?
The common forms are α, β, γ, and δ chains.
p.3
Oxygen and Carbon Dioxide Diffusion
What is the partial pressure of oxygen (PO2) in air and water at equilibrium?
At equilibrium, the PO2 in air and water is equal.
p.13
Oxygen-Hemoglobin Dissociation Curve
Is the binding of oxygen to hemoglobin linear?
No, the binding of oxygen to hemoglobin is not linear.
p.14
Oxygen-Hemoglobin Dissociation Curve
What does the large reservoir of oxygen in the blood allow for?
It allows cells to draw on it when metabolism increases.
p.10
Hemoglobin Structure and Function
What is the composition of a small portion (2.5%) of adult hemoglobin (HbA2)?
HbA2 has two α chains and two δ chains.
p.19
Carbon Dioxide Transport in Blood
How does hemoglobin help buffer the blood pH?
Hemoglobin binds to hydrogen ions (H+) to form Hb•H, preventing sharp changes in body pH.
p.19
Carbon Dioxide Transport in Blood
What is the primary form of CO2 transport in the blood?
As bicarbonate ions (HCO3-) in plasma
p.19
Carbon Dioxide Transport in Blood
What happens to CO2 in the alveoli?
CO2 is transported to the lungs to be exhaled.
p.19
Carbon Dioxide Transport in Blood
What is the role of the chloride antiport in CO2 transport?
It exchanges HCO3- leaving the RBC with Cl- to maintain the cell’s electrical neutrality.
