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What are the primary functions of the respiratory system?
What are the primary functions of the respiratory system?
The primary function of the respiratory system is to obtain oxygen for use by the body's cells and eliminate carbon dioxide that cells produce.
The primary function of the respiratory system is to obtain oxygen for use by the body's cells and eliminate carbon dioxide that cells produce.
True
Breathing, also known as ______, consists of two cyclic phases: inhalation and exhalation.
Breathing, also known as ______, consists of two cyclic phases: inhalation and exhalation.
pulmonary ventilation
Which of the following describes the process of external respiration?
Which of the following describes the process of external respiration?
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Which of these muscles is responsible for the downward movement and flattening of the diaphragm during inspiration?
Which of these muscles is responsible for the downward movement and flattening of the diaphragm during inspiration?
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Expiration is an active process that requires muscular contractions.
Expiration is an active process that requires muscular contractions.
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What is the term for the maximum volume of air that can be inspired over the inspiration of a tidal volume?
What is the term for the maximum volume of air that can be inspired over the inspiration of a tidal volume?
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What is the volume of air that remains in the lungs after a maximal expiration called?
What is the volume of air that remains in the lungs after a maximal expiration called?
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What is the sum of vital capacity and residual volume?
What is the sum of vital capacity and residual volume?
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What are the three basic steps of respiration?
What are the three basic steps of respiration?
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What is the process of breathing in called?
What is the process of breathing in called?
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Which of the following occurs to the air pressure inside the lungs during each inhalation?
Which of the following occurs to the air pressure inside the lungs during each inhalation?
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The pressure in the lungs is greater than the pressure of the atmosphere during exhalation.
The pressure in the lungs is greater than the pressure of the atmosphere during exhalation.
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What causes exhalation during quiet breathing?
What causes exhalation during quiet breathing?
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Which of the following describes deoxygenated blood?
Which of the following describes deoxygenated blood?
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External respiration involves the exchange of gases between the alveoli of the lungs and the blood in pulmonary capillaries.
External respiration involves the exchange of gases between the alveoli of the lungs and the blood in pulmonary capillaries.
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As blood flows through the pulmonary capillaries, it picks up O₂ from alveolar air and unloads CO₂ into alveolar air.
As blood flows through the pulmonary capillaries, it picks up O₂ from alveolar air and unloads CO₂ into alveolar air.
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What is the name for the exchange of gases that occurs between blood and tissue cells?
What is the name for the exchange of gases that occurs between blood and tissue cells?
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The left ventricle pumps oxygenated blood into the aorta and then to the systemic arteries, ultimately reaching systemic capillaries.
The left ventricle pumps oxygenated blood into the aorta and then to the systemic arteries, ultimately reaching systemic capillaries.
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What is the primary way oxygen is transported in the blood?
What is the primary way oxygen is transported in the blood?
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Each hemoglobin molecule can bind to four oxygen molecules.
Each hemoglobin molecule can bind to four oxygen molecules.
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The affinity of hemoglobin for oxygen is always constant, regardless of factors like pH or temperature.
The affinity of hemoglobin for oxygen is always constant, regardless of factors like pH or temperature.
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Which of the following factors reduces the affinity of hemoglobin for oxygen?
Which of the following factors reduces the affinity of hemoglobin for oxygen?
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How is carbon dioxide primarily transported in the blood?
How is carbon dioxide primarily transported in the blood?
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Bicarbonate ions are formed by the reaction of carbon dioxide with water in the presence of the enzyme carbonic anhydrase.
Bicarbonate ions are formed by the reaction of carbon dioxide with water in the presence of the enzyme carbonic anhydrase.
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What is the term used to describe the temporary cessation of breathing?
What is the term used to describe the temporary cessation of breathing?
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What is the term used to describe abnormally rapid respirations?
What is the term used to describe abnormally rapid respirations?
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What is the term used to describe abnormally slow respiration?
What is the term used to describe abnormally slow respiration?
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What is the term used to describe labored breathing or shortness of breath?
What is the term used to describe labored breathing or shortness of breath?
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What is the term used to describe a decrease in arterial oxygen tension in the blood?
What is the term used to describe a decrease in arterial oxygen tension in the blood?
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What is the term used to describe a decrease in oxygen supply to the tissues and cells?
What is the term used to describe a decrease in oxygen supply to the tissues and cells?
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What is the term used to describe an increase in the partial pressure of carbon dioxide in the blood?
What is the term used to describe an increase in the partial pressure of carbon dioxide in the blood?
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What is the term used to describe a decreased amount of carbon dioxide in the blood?
What is the term used to describe a decreased amount of carbon dioxide in the blood?
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What is the term used to describe the portion of the tracheobronchial tree that does not participate in gas exchange?
What is the term used to describe the portion of the tracheobronchial tree that does not participate in gas exchange?
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What is the term used to describe bluish discoloration of the skin or mucous membranes due to hemoglobin carrying reduced amounts of oxygen?
What is the term used to describe bluish discoloration of the skin or mucous membranes due to hemoglobin carrying reduced amounts of oxygen?
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What is the term used to describe the pressure between the two pleural layers in the pleural cavity?
What is the term used to describe the pressure between the two pleural layers in the pleural cavity?
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What is the term used to describe the pressure within the tiny gas-exchanging structures of the lungs?
What is the term used to describe the pressure within the tiny gas-exchanging structures of the lungs?
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Which law states that the total pressure of a mixture of gases equals the sum of the partial pressures of each gas?
Which law states that the total pressure of a mixture of gases equals the sum of the partial pressures of each gas?
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Which law describes the relationship between the weight of a gas dissolved in a liquid and its partial pressure?
Which law describes the relationship between the weight of a gas dissolved in a liquid and its partial pressure?
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Which law describes the inverse relationship between the volume of a gas and its pressure, at a constant temperature?
Which law describes the inverse relationship between the volume of a gas and its pressure, at a constant temperature?
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What is the normal respiration rate for an adult?
What is the normal respiration rate for an adult?
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What is the normal pH range for arterial blood?
What is the normal pH range for arterial blood?
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What are the major mechanisms involved in the regulation of respiration?
What are the major mechanisms involved in the regulation of respiration?
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The respiratory center is located in the medulla oblongata and pons of the brainstem.
The respiratory center is located in the medulla oblongata and pons of the brainstem.
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The dorsal respiratory group in the medulla oblongata is responsible for inspiration, while the ventral respiratory group is responsible for expiration.
The dorsal respiratory group in the medulla oblongata is responsible for inspiration, while the ventral respiratory group is responsible for expiration.
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What are the three important chemical factors controlling respiration?
What are the three important chemical factors controlling respiration?
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Where are peripheral chemoreceptors located?
Where are peripheral chemoreceptors located?
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Study Notes
Respiratory System Functions
- The respiratory system supplies the body with oxygen and disposes of carbon dioxide.
- It filters inspired air.
- It produces sound.
- It eliminates excess water and heat from the body.
- It regulates blood pH.
Breathing (Pulmonary Ventilation)
- Breathing is a two-phased process:
- Inhalation (inspiration): Draws gases into the lungs.
- Exhalation (expiration): Forces gases out of the lungs.
Respiratory Events
- Pulmonary ventilation: Exchange of gases between lungs and atmosphere.
- External respiration: Exchange of gases between alveoli and pulmonary capillaries.
- Internal respiration: Exchange of gases between systemic capillaries and tissue cells.
Phases of Pulmonary Ventilation
- Inspiration (Inhalation): An active process requiring energy. The diaphragm contracts, moving downward and flattening.
- Expiration (Exhalation): A passive process. The diaphragm relaxes. The elasticity of the lungs and thoracic cage allows them to return to their normal size and shape. This occurs when phrenic nerves stimulate the two processes.
Lung Volumes
- Minute Ventilation (MV): 12 breaths/min * 500 mL/breath = 6 liters/min. Total lung capacity.
- Tidal Volume (TV): Volume inspired or expired with each normal breath. = 500 mL
- Inspiratory Reserve Volume (IRV): Maximum volume that can be inspired over the tidal volume. Used during exercise. Male 3100 mL/Female 1900 mL
- Expiratory Reserve Volume (ERV): Maximum volume that can be expired after a tidal volume. Male 1200 mL/Female 700 mL
- Residual Volume (RV): Volume that remains in the lungs after a maximal expiration. Male 1200 mL/Female 1100 mL
Lung Capacities
- Inspiratory Capacity: IRV + TV = 3600 mL in males and 2400 mL in females.
- Functional Residual Capacity: RV + ERV = 2400 mL in males and 1800 mL in females.
- Vital Capacity: IRV + TV + ERV = 4800 mL in males and 3100 mL in females.
- Total Lung Capacity: VC + RV = 6000 mL in males and 4200 mL in females
Physiology of Respiration
- Respiration has three basic steps:
- Pulmonary ventilation: Inhalation (inflow) and exhalation (outflow) of air.
- External respiration: Exchange of gases between alveoli and blood.
- Internal respiration: Exchange of gases between blood and tissue cells.
Inhalation
- The air pressure inside the lungs equals the air pressure of the atmosphere (about 760 mmHg).
- For air to flow into the lungs, the pressure inside the alveoli must become lower than atmospheric pressure.
- This is achieved by increasing the size of the lungs.
Exhalation
- Exhalation begins when the respiratory muscles relax.
- The diaphragm moves superiorly and the ribs are depressed.
- Lung and chest wall elasticity causes them to return to their initial size and shape.
- Recoil of elastic fibers.
- Inward pull of surface tension (alveolar fluid).
- Normal exhalation is a passive process.
External Respiration/Pulmonary Gas Exchange
- This process results in the diffusion of O2 from the alveoli to the blood in the pulmonary capillaries and the diffusion of CO2 in the opposite direction.
- Deoxygenated blood is converted to oxygenated blood in the lungs.
- The exchange of gases occurs by diffusion.
Internal Respiration
- Oxygenated blood is pumped to the systemic capillaries through the aorta and systemic arteries.
- The exchange of O2 and CO2 between systemic capillaries and tissue cells is internal respiration.
Oxygen Transport
- About 1.5% of inhaled O2 is dissolved in the blood plasma.
- About 98.5% of blood O2 is bound to hemoglobin in red blood cells.
- Hemoglobin binds oxygen reversibly to form oxyhemoglobin.
- Oxygen is released from hemoglobin as blood flows through tissue capillaries.
Factors Affecting Hemoglobin Affinity for Oxygen
- Acidity (pH): Lower pH (higher acidity) decreases hemoglobin's affinity for oxygen.
- Partial pressure of carbon dioxide (PCO2): Higher PCO2 decreases hemoglobin's affinity for oxygen.
- Temperature: Higher temperature decreases hemoglobin's affinity for oxygen.
- 2,3-Biphosphoglycerate (BPG): Higher BPG decreases hemoglobin's affinity for oxygen.
Acidity (pH)
- Increased acidity (lower pH) decreases hemoglobin's affinity for oxygen and causes oxygen to be released from hemoglobin.
Partial Pressure of Carbon Dioxide (PCO2)
- Increased PCO2 decreases hemoglobin's affinity for oxygen, causing oxygen to be released from hemoglobin.
Temperature
- Increased temperature decreases hemoglobin's affinity for oxygen, causing oxygen to be released from hemoglobin.
2,3-Biphosphoglycerate (BPG)
- BPG is formed in red blood cells and decreases hemoglobin's affinity for oxygen.
CO2 Transport
- Carbon dioxide is transported in the blood in three forms:
- Dissolved CO2: A small percentage of CO2 is dissolved in the blood plasma.
- Carbamino compounds: About 23% of CO2 combines with blood proteins to form carbamino compounds. This involves CO2 binding to amino acids in globin.
- Bicarbonate ions: Most CO2 (around 70%) is transported as bicarbonate ions (HCO3-). CO2 diffuses into the systemic capillaries and red blood cells, where it reacts with water, forming carbonic acid (H2CO3). Carbonic acid dissociates into hydrogen ions (H+) and bicarbonate ions (HCO3-).
Regulation of Respiration
- Respiratory rate and depth are controlled by nervous and chemical factors.
- Nervous factors involve the respiratory centers in the medulla and pons.
- Chemical factors include the concentrations of CO2, H+ (pH), and O2 in the blood.
Medullary Rhythmicity Area
- The medullary rhythmicity area in the medulla oblongata controls the basic rhythm of respiration.
- Inspiratory center: Sets the basic rhythm of breathing by sending signals to respiratory muscles.
- Expiratory center: Causes forceful exhalation by sending signals to intercostal and abdominal muscles .
Pneumotaxic Area
- The pneumotaxic area in the pons helps regulate the rate of breathing by sending inhibitory signals to the inspiratory center, preventing overinflation of the lungs.
Apneustic Area
- The apneustic area in the pons influences the duration of inhalation, promoting a prolonged inhalation.
Chemical Regulation of Respiration
- The respiratory rate and depth are adjusted based on the concentration of CO2, H+ (pH), and O2 in the blood.
- Increased levels of CO2 or decreased levels of O2 stimulate the chemoreceptors to increase respiration and vice-versa.
Respiratory System Terminologies
- Apnea: Temporary cessation of breathing.
- Tachypnea: Abnormally rapid respirations.
- Bradypnea: Abnormally slow respirations.
- Dyspnea: Labored breathing or shortness of breath.
- Hypoxemia: Low arterial blood oxygen.
- Hypoxia: Low tissue oxygen.
- Hypercapnia: High blood carbon dioxide.
- Hypocapnia: Low blood carbon dioxide.
- Physiological dead space: Portion of respiratory system that doesn't participate in gas exchange.
- Cyanosis: Bluish discoloration of the skin and mucous membranes due to low oxygen levels in the blood.
- Intrapleural (intrathoracic) pressure: Pressure between pleural membranes.
Additional Concepts
- Alveolar (intrapulmonic) pressure: The pressure inside the alveoli.
- Diffusion: The movement of molecules from an area of high concentration to an area of low concentration.
- Osmosis: The movement of solvent across a semipermeable membrane from an area of low solute concentration to an area of high solute concentration.
- Dalton's law: The total pressure of a gas mixture is equal to the sum of the partial pressures of each gas in the mixture.
- Henry's law: The amount of gas dissolved in a liquid is directly proportional to the partial pressure of the gas.
- Boyle's law: At constant temperature, the volume of a gas is inversely proportional to its pressure
Normal Respiratory Values
- Normal respiration: 12 – 16 breaths/minute.
- Normal arterial blood gas values:
- pH: 7.35–7.45
- PaO2: (80 to 100 mmHg)
- SaO2: (95% to 98%)
- PCO2: 35–45 mmHg
- HCO3: 22–27 mEq/L
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Description
Explore the key functions of the respiratory system and the phases of pulmonary ventilation. This quiz covers essential processes such as inhalation and exhalation, as well as gas exchange mechanisms. Test your knowledge on how our body interacts with oxygen and carbon dioxide.
