Since human cells are primarily reliant on aerobic metabolism, it is of vital importance to efficiently obtain oxygen from the environment and bring it to the tissues while excreting the byproduct of cellular respiration Respiration The act of breathing with the lungs, consisting of inhalation, or the taking into the lungs of the ambient air, and of exhalation, or the expelling of the modified air which contains more carbon dioxide than the air taken in. Nose and Nasal Cavity: Anatomy (CO2). Respiration Respiration The act of breathing with the lungs, consisting of inhalation, or the taking into the lungs of the ambient air, and of exhalation, or the expelling of the modified air which contains more carbon dioxide than the air taken in. Nose and Nasal Cavity: Anatomy involves both the respiratory and circulatory systems. There are 4 processes that supply the body with O2 and dispose of CO2. The respiratory system is involved in pulmonary ventilation Ventilation The total volume of gas inspired or expired per unit of time, usually measured in liters per minute. Ventilation: Mechanics of Breathing and external respiration Respiration The act of breathing with the lungs, consisting of inhalation, or the taking into the lungs of the ambient air, and of exhalation, or the expelling of the modified air which contains more carbon dioxide than the air taken in. Nose and Nasal Cavity: Anatomy, while the circulatory system is responsible for transport and internal respiration Respiration The act of breathing with the lungs, consisting of inhalation, or the taking into the lungs of the ambient air, and of exhalation, or the expelling of the modified air which contains more carbon dioxide than the air taken in. Nose and Nasal Cavity: Anatomy. Pulmonary ventilation Ventilation The total volume of gas inspired or expired per unit of time, usually measured in liters per minute. Ventilation: Mechanics of Breathing (breathing) represents movement of air into and out of the lungs Lungs Lungs are the main organs of the respiratory system. Lungs are paired viscera located in the thoracic cavity and are composed of spongy tissue. The primary function of the lungs is to oxygenate blood and eliminate CO2. Lungs: Anatomy. External respiration Respiration The act of breathing with the lungs, consisting of inhalation, or the taking into the lungs of the ambient air, and of exhalation, or the expelling of the modified air which contains more carbon dioxide than the air taken in. Nose and Nasal Cavity: Anatomy, or gas exchange, is represented by the O2 and CO2 exchange between the lungs Lungs Lungs are the main organs of the respiratory system. Lungs are paired viscera located in the thoracic cavity and are composed of spongy tissue. The primary function of the lungs is to oxygenate blood and eliminate CO2. Lungs: Anatomy and the blood.
Last updated: 2 Jun, 2021
Gas exchange occurs at the level of the alveoli Alveoli Small polyhedral outpouchings along the walls of the alveolar sacs, alveolar ducts and terminal bronchioles through the walls of which gas exchange between alveolar air and pulmonary capillary blood takes place. Acute Respiratory Distress Syndrome (ARDS) in the lungs Lungs Lungs are the main organs of the respiratory system. Lungs are paired viscera located in the thoracic cavity and are composed of spongy tissue. The primary function of the lungs is to oxygenate blood and eliminate CO2. Lungs: Anatomy and capillaries Capillaries Capillaries are the primary structures in the circulatory system that allow the exchange of gas, nutrients, and other materials between the blood and the extracellular fluid (ECF). Capillaries are the smallest of the blood vessels. Because a capillary diameter is so small, only 1 RBC may pass through at a time. Capillaries: Histology of the pulmonary circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment.
During gas exchange, O₂ and CO₂ must cross the pulmonary membrane. This process is driven by multiple complex forces determined by the physical properties of these gases.
The rate of gas exchange is determined by the efficiency of the exchange across the pulmonary membrane and the speed at which it can be brought there from the air (for O₂) or from the body (for CO₂).
O₂ and CO₂ must be transported through the bloodstream to reach sites of gas exchange.
Saturation of Hemoglobin:
Percentage of bound hemoglobin increases with the concentration of O2. Notice the letter A, which signifies the saturation of hemoglobin in arterial blood (close to 99%). The letter V signifies the hemoglobin saturation of venous blood.
Dissociation
Dissociation
Defense Mechanisms curve of Hemoglobin:
Shows the right and left shifts that can occur when oxygen delivery to the tissues is increased or decreased, respectively.
Percentages of CO2 transported in the
plasma
Plasma
The residual portion of blood that is left after removal of blood cells by centrifugation without prior blood coagulation.
Transfusion Products:
Notice how 90% is converted by the
Carbonic anhydrase
Carbonic anhydrase
A family of zinc-containing enzymes that catalyze the reversible hydration of carbon dioxide. They play an important role in the transport of carbon dioxide from the tissues to the lung.
Carbonic Anhydrase Inhibitors into HCO3– inside
red blood cells
Red blood cells
Erythrocytes, or red blood cells (RBCs), are the most abundant cells in the blood. While erythrocytes in the fetus are initially produced in the yolk sac then the liver, the bone marrow eventually becomes the main site of production.
Erythrocytes: Histology.
Dissociation
Dissociation
Defense Mechanisms curve of Hb and CO2:
Notice how PCO2 increases from the arterial (a) to the venous side (v). The
dissociation
Dissociation
Defense Mechanisms curve is elevated with the decrease in PO2, referencing the fact that a low O2 concentration allows for more CO2 to be bound to Hb.
Ventilation Ventilation The total volume of gas inspired or expired per unit of time, usually measured in liters per minute. Ventilation: Mechanics of Breathing and perfusion are the mechanisms that transport O₂ and CO₂ between the pulmonary membrane and the body’s tissues.
Perfusion is the flow Flow Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls. Vascular Resistance, Flow, and Mean Arterial Pressure of blood to pulmonary vasculature.
Diagram explaining the mechanisms of recruitment Recruitment Skeletal Muscle Contraction and distension of blood vessels when mean Mean Mean is the sum of all measurements in a data set divided by the number of measurements in that data set. Measures of Central Tendency and Dispersion pulmonary arterial blood pressure is increased
Image by Lecturio. License: CC BY-NC-SA 4.0Chart showing the
relationship
Relationship
A connection, association, or involvement between 2 or more parties.
Clinician–Patient Relationship between lung volume (x-
axis
Axis
The second cervical vertebra.
Vertebral Column: Anatomy) and pulmonary
vascular resistance
Vascular Resistance
The force that opposes the flow of blood through a vascular bed. It is equal to the difference in blood pressure across the vascular bed divided by the cardiac output.
Vascular Resistance, Flow, and Mean Arterial Pressure (y-
axis
Axis
The second cervical vertebra.
Vertebral Column: Anatomy):
At low lung volume (RV:
residual volume
Residual volume
The volume of air remaining in the lungs at the end of a maximal expiration. Common abbreviation is rv.
Ventilation: Mechanics of Breathing) and at very high lung volume (
Total Lung Capacity
Total lung capacity
The volume of air contained in the lungs at the end of a maximal inspiration. It is the equivalent to each of the following sums: vital capacity plus residual volume; inspiratory capacity plus functional residual capacity; tidal volume plus inspiratory reserve volume plus functional residual capacity; or tidal volume plus inspiratory reserve volume plus expiratory reserve volume plus residual volume.
Ventilation: Mechanics of Breathing: TLC)
vascular resistance
Vascular Resistance
The force that opposes the flow of blood through a vascular bed. It is equal to the difference in blood pressure across the vascular bed divided by the cardiac output.
Vascular Resistance, Flow, and Mean Arterial Pressure increases.
Diagram explaining the mechanisms of recruitment Recruitment Skeletal Muscle Contraction and distension of blood vessels when mean Mean Mean is the sum of all measurements in a data set divided by the number of measurements in that data set. Measures of Central Tendency and Dispersion pulmonary arterial blood pressure is increased
Image by Lecturio. License: CC BY-NC-SA 4.0 Vessel dilation effect:
The negative pleural pressure exerted on the
alveoli
Alveoli
Small polyhedral outpouchings along the walls of the alveolar sacs, alveolar ducts and terminal bronchioles through the walls of which gas exchange between alveolar air and pulmonary capillary blood takes place.
Acute Respiratory Distress Syndrome (ARDS) stretches the walls of the blood vessels and increases their diameter.
Overview of pulmonary blood flow Blood flow Blood flow refers to the movement of a certain volume of blood through the vasculature over a given unit of time (e.g., mL per minute). Vascular Resistance, Flow, and Mean Arterial Pressure
Image by Lecturio. License: CC BY-NC-SA 4.0Zone 1 (Apex) of the lung and the effect of gravity on it:
Arterial pressure (Pa) is lower than alveolar pressure (PA), making the
flow
Flow
Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls.
Vascular Resistance, Flow, and Mean Arterial Pressure of blood difficult if not impossible. The
relationship
Relationship
A connection, association, or involvement between 2 or more parties.
Clinician–Patient Relationship between pressures can be seen in the green box.
Zone 2 of the lung and the effect of gravity on it:
There’s more
blood flow
Blood flow
Blood flow refers to the movement of a certain volume of blood through the vasculature over a given unit of time (e.g., mL per minute).
Vascular Resistance, Flow, and Mean Arterial Pressure allowed by the increase in arterial blood pressure. The
relationship
Relationship
A connection, association, or involvement between 2 or more parties.
Clinician–Patient Relationship between pressures can be seen in the green box.
Zone 3 (Base) of the lung and the effect of gravity on it:
It’s the zone with the greatest
blood flow
Blood flow
Blood flow refers to the movement of a certain volume of blood through the vasculature over a given unit of time (e.g., mL per minute).
Vascular Resistance, Flow, and Mean Arterial Pressure in the lung. The pull of gravity makes more blood available and the arterial blood pressure greater than the alveolar pressure. The
relationship
Relationship
A connection, association, or involvement between 2 or more parties.
Clinician–Patient Relationship between pressures can be seen in the green box.
There are 2 important PO₂ differences (gradients):
Arterial-venous (a-v) difference in PO2 between venous and arterial blood:
Pressures of O2 and CO2 in the
alveoli
Alveoli
Small polyhedral outpouchings along the walls of the alveolar sacs, alveolar ducts and terminal bronchioles through the walls of which gas exchange between alveolar air and pulmonary capillary blood takes place.
Acute Respiratory Distress Syndrome (ARDS) and systemic
circulation
Circulation
The movement of the blood as it is pumped through the cardiovascular system.
ABCDE Assessment before and after gas exchange.
Diagram of a RIGHT-TO-LEFT shunt:
See the
communication
Communication
The exchange or transmission of ideas, attitudes, or beliefs between individuals or groups.
Decision-making Capacity and Legal Competence that allows blood to skip gas exchange and lower the arterial pressure of O2.
PO2 gradients in pulmonary and systemic circulations:
See the A-a gradient at the point of
communication
Communication
The exchange or transmission of ideas, attitudes, or beliefs between individuals or groups.
Decision-making Capacity and Legal Competence between the pulmonary
capillaries
Capillaries
Capillaries are the primary structures in the circulatory system that allow the exchange of gas, nutrients, and other materials between the blood and the extracellular fluid (ECF). Capillaries are the smallest of the blood vessels. Because a capillary diameter is so small, only 1 RBC may pass through at a time.
Capillaries: Histology and the systemic arterial
circulation
Circulation
The movement of the blood as it is pumped through the cardiovascular system.
ABCDE Assessment. The a-v gradient would be the difference between the PO2 of the systemic arterial
circulation
Circulation
The movement of the blood as it is pumped through the cardiovascular system.
ABCDE Assessment before the
capillaries
Capillaries
Capillaries are the primary structures in the circulatory system that allow the exchange of gas, nutrients, and other materials between the blood and the extracellular fluid (ECF). Capillaries are the smallest of the blood vessels. Because a capillary diameter is so small, only 1 RBC may pass through at a time.
Capillaries: Histology and the PO2 of the systemic venous
circulation
Circulation
The movement of the blood as it is pumped through the cardiovascular system.
ABCDE Assessment after the
capillaries
Capillaries
Capillaries are the primary structures in the circulatory system that allow the exchange of gas, nutrients, and other materials between the blood and the extracellular fluid (ECF). Capillaries are the smallest of the blood vessels. Because a capillary diameter is so small, only 1 RBC may pass through at a time.
Capillaries: Histology.
Diagrammatic examples of
ventilation
Ventilation
The total volume of gas inspired or expired per unit of time, usually measured in liters per minute.
Ventilation: Mechanics of Breathing (V) to perfusion (Q) mismatch:
On the right, an example of low
ventilation
Ventilation
The total volume of gas inspired or expired per unit of time, usually measured in liters per minute.
Ventilation: Mechanics of Breathing to high perfusion can be seen. On the left, an example of high
ventilation
Ventilation
The total volume of gas inspired or expired per unit of time, usually measured in liters per minute.
Ventilation: Mechanics of Breathing to low perfusion can be seen. In the center is a normal situation of
ventilation
Ventilation
The total volume of gas inspired or expired per unit of time, usually measured in liters per minute.
Ventilation: Mechanics of Breathing to perfusion with a relation of 1 to 1.
Ventilation
Ventilation
The total volume of gas inspired or expired per unit of time, usually measured in liters per minute.
Ventilation: Mechanics of Breathing/Perfusion relation applied to the apex of the upright lung of a healthy individual:
Reduced perfusion of the Apex (right), the inflating effect of the gravity due to the weight of the lung (center) and the resulting parameters during
inspiration
Inspiration
Ventilation: Mechanics of Breathing (right). Notice the increase of the V/Q (V/P) ratio due to the increased
ventilation
Ventilation
The total volume of gas inspired or expired per unit of time, usually measured in liters per minute.
Ventilation: Mechanics of Breathing and the reduced perfusion.
Ventilation
Ventilation
The total volume of gas inspired or expired per unit of time, usually measured in liters per minute.
Ventilation: Mechanics of Breathing/Perfusion relation applied to the base of the upright lung of a healthy individual:
See the increased perfusion of the Base (right), the compressing effect of the gravity due to the weight of the lung (center) and the resulting parameters during
inspiration
Inspiration
Ventilation: Mechanics of Breathing (right). The V/Q (V/P) ratio is decreased due to the increased perfusion.