Week 1 Flashcards
What are the primary functions of the respiratory system?
- Removal of CO₂ from tissues → blood → air.
- Supply of O₂ to tissues: air → blood → cells.
- Pulmonary ventilation: inflow and outflow of air between the atmosphere and lungs.
- Gas exchange between lung alveoli and blood.
- Gas transport in blood.
- Gas exchange between blood and tissues.
- Cellular respiration: Utilization of O₂ by cells (mitochondria) to generate energy (ATP) and produce CO₂.
What are the two main zones of the lower respiratory passages, and what are their functions?
- Conducting zone (Generations 1-16):
- Includes trachea , bronchi (1-4) , bronchioles (5-16) and terminal bronchioles.
- Function: Conducts air to the respiratory zone.
- supplied by : bronchial systemic circulation
- Respiratory zone (Generations 17-23):
- Includes respiratory bronchioles(17-19), alveolar ducts (20-22) , and alveolar sacs(23).
- Function: Site of gas exchange (alveoli).
-Supplied by: pulmonary circulation
What muscles are involved in normal quiet breathing, and what is their role?
Inspiration (active process):
- Diaphragm (75% of work): Contracts and descends, increasing the vertical diameter of the thorax.
- External intercostals: Elevate the ribs, increasing the transverse and anteroposterior diameter of the thorax.
Expiration (passive process):
- Relaxation of inspiratory muscles and elastic recoil of the lungs.
What is partial pressure, and how does it differ in inspired, alveolar, and expired gases?
Partial pressure: The pressure exerted by a single gas in a mixture of gases.
- Inspired air: Contains higher O₂ and lower CO₂.
- Alveolar air: Contains lower O₂ and higher CO₂ due to gas exchange.
- Expired air: A mixture of alveolar air and dead space air, with more O₂ and less CO₂ than alveolar air.
What are the different types of dead space, and how are they measured?
- Anatomical dead space:
- Upper respiratory tract and conducting zone (no alveoli).
- Volume: ~150 cm³ (1/3 of tidal volume).
- Physiological dead space:
- Anatomical dead space + alveolar dead space (non-functioning or non-perfused alveoli).
- In normal lungs, physiological dead space = anatomical dead space.
- In diseased lungs (e.g., emphysema, pulmonary embolism), physiological dead space > anatomical dead space.
What are the four main lung volumes, and how are they measured?
- Tidal Volume (TV): 500 ml – air inhaled or exhaled with each breath.
- Inspiratory Reserve Volume (IRV): 3000 ml – air that can be inhaled beyond tidal volume.
- Expiratory Reserve Volume (ERV): 1100 ml – air that can be exhaled beyond tidal volume.
- Residual Volume (RV): 1200 ml – air remaining in the lungs after maximal expiration (cannot be measured by spirometry).
What are the four main lung capacities, and how are they calculated?
- Inspiratory Capacity (IC): TV + IRV = ~3500 ml.
- Functional Residual Capacity (FRC): ERV + RV = ~2300 ml.
- Vital Capacity (VC): TV + IRV + ERV = ~4600 ml.
- Total Lung Capacity (TLC): TV + IRV + ERV + RV = ~5800 ml.
What are the steps involved in the mechanics of breathing?
- Changes in the size of the thoracic cage (distention and contraction).
- Changes in lung size due to connection to the chest wall via pleura.
- Creation of a pressure gradient between alveoli and atmospheric air.
- Air inflow (inspiration) or outflow (expiration).
What muscles are involved in forced breathing, and how do they differ from normal breathing?
Forced Inspiration:
- Stronger contraction of diaphragm and external intercostals.
- Accessory muscles: sternomastoid, serratus anterior, scalene muscles.
Forced Expiration:
- Internal intercostal muscles and abdominal wall muscles contract to increase intra-abdominal pressure, pushing the diaphragm upward.
What is the significance of FEV1/FVC ratio in distinguishing between obstructive and restrictive lung diseases?
Normal: FEV1/FVC = 80%.
Obstructive Lung Disease (e.g., asthma, emphysema):
- FEV1 is significantly reduced compared to FVC.
- FEV1/FVC < 75%.
Restrictive Lung Disease (e.g., pulmonary fibrosis):
- FVC is significantly reduced compared to FEV1.
- FEV1/FVC is normal or increased.
How is pulmonary ventilation calculated, and what factors influence it?
Pulmonary Ventilation (VE):
- VE = Tidal Volume (TV) x Respiratory Rate (RR).
- At rest: 500 ml x 12 breaths/min = 6 L/min.
Factors influencing VE:
- Depth of breathing (TV).
- Respiratory rate (RR).
- During exercise, both depth and rate increase, leading to higher VE.
What is alveolar ventilation, and how is it different from pulmonary ventilation?
Alveolar Ventilation (VA):
- Volume of air reaching the alveoli and participating in gas exchange.
- VA = (TV - Dead Space) x RR.
Difference from Pulmonary Ventilation (VE):
- VE includes all air flowing in and out of the respiratory tract, while VA only includes air that reaches the alveoli.
What is dead space ventilation, and how does it affect alveolar ventilation?
Dead Space Ventilation (VD):
- Volume of air that does not participate in gas exchange (anatomical dead space).
- VD = Dead Space Volume x RR.
Effect on Alveolar Ventilation (VA):
- VA = VE - VD.
- If dead space increases (e.g., in emphysema), alveolar ventilation decreases.
What are the clinical implications of hypoventilation and hyperventilation?
Hypoventilation:
- Decreased alveolar ventilation.
- Leads to increased alveolar CO₂ (hypercapnia) and decreased O₂.
Hyperventilation:
- Increased alveolar ventilation.
- Leads to decreased alveolar CO₂ (hypocapnia) and increased O₂.
What is the alveolar ventilation equation, and how is it used?
Alveolar Ventilation Equation:
- VA = (VCO₂ / PACO₂) x constant.
- VCO₂ = volume of CO₂ produced per minute (~200 ml/min).
- PACO₂ = alveolar partial pressure of CO₂ (~40 mmHg).
- Constant = 0.863 (for mmHg).
Example:
- VA = (200 / 40) x 0.863 = 4.315 L/min.
What are the two main zones of the upper respiratory passages, and what are their functions?
-includes : Nose, Mouth, Pharynx and Larynx
-function :Warming, humidification, cleaning and filtering AIR.
Structure of the airways
- Trachea and bronchi have cartilage ring to prevent collapse
- bronchioles is kept open by elastic tension
What are the primary functions of the respiratory system?
- Removal of CO₂ from tissues → blood → air.
- Supply of O₂ to tissues: air → blood → cells.
- Pulmonary ventilation: inflow and outflow of air between the atmosphere and lungs.
- Gas exchange between lung alveoli and blood.
- Gas transport in blood.
- Cellular respiration: Utilization of O₂ by cells (mitochondria) to generate energy (ATP) and produce CO₂.
What are the functions of the upper respiratory passages?
- Air conditioning: Warming, humidification, cleaning, and filtering air (particles >2μm stick to mucous and are repelled by cilia).
- Pharynx: Common passage for air and food. During swallowing, respiration is inhibited, and air passages are protected.
What are the two zones of the lower respiratory passages, and what are their functions?
- Conducting zone (Generations 1-16):
- Trachea, bronchi, bronchioles.
- Function: Conduct air to the respiratory zone.
- Respiratory zone (Generations 17-23):
- Respiratory bronchioles, alveolar ducts, alveolar sacs (alveoli).
- Function: Gas exchange occurs here.
How does the structure of airways change from the trachea to the bronchioles?
- Trachea and bronchi: Contain cartilage to prevent collapse.
- Bronchioles: No cartilage, kept open by elastic tension of alveolar walls.
- Smooth muscle: Present in all airways except alveoli.
- Parasympathetic stimulation: Bronchoconstriction.
- Sympathetic stimulation: Bronchodilation.
What is the relationship between the lungs, chest wall, and pleura?
- Pleura: Each lung is surrounded by a pleural sac with two layers:
- Visceral pleura: Covers the lung.
- Parietal pleura: Lines the chest wall.
- Pleural fluid: Lubricates and allows lungs to slide over the chest wall during breathing.
- Excess fluid: Pleural effusion can lead to lung collapse.
What are the phases of the normal respiratory cycle?
- Inspiration (1.3 sec): Active process, air flows into the lungs.
- Expiration (1.7 sec): Passive process, air flows out of the lungs.
- Expiratory pause (1 sec): Brief pause before the next cycle.
- Respiratory rate: 12-18 breaths/min in adults, 30-40/min in infants.
What are the steps involved in the mechanics of breathing?
- Thoracic cage changes size: Ribs and diaphragm move.
- Lung size changes: Due to connection to the chest wall via pleura.
- Pressure gradient: Created between alveoli and atmospheric air.
- Airflow: Air moves in or out of the lungs.
What muscles are involved in inspiration, and what are their roles?
- Diaphragm: Responsible for 75% of resting inspiratory activity.
- Contracts and descends, increasing the vertical diameter of the thorax.
- External intercostals: Elevate and evert the ribs, increasing the transverse and anteroposterior diameter of the thorax.
What muscles are involved in forced breathing?
- Inspiration:
- Stronger contraction of diaphragm and external intercostals.
- Accessory muscles: Sternomastoid, serratus anterior, scalene muscles.
- Expiration:
- Internal intercostal muscles and abdominal wall muscles contract to force air out.
What are the four main lung volumes?
- Tidal Volume (TV): 500 mL, air inhaled/exhaled with each breath.
- Inspiratory Reserve Volume (IRV): 3000 mL, air inhaled during forced inspiration.
- Expiratory Reserve Volume (ERV): 1100 mL, air exhaled during forced expiration.
- Residual Volume (RV): 1200 mL, air remaining in the lungs after maximal expiration.
What are the four main lung capacities, and how are they calculated?
- Inspiratory Capacity (IC): TV + IRV = ~3500 mL.
- Functional Residual Capacity (FRC): ERV + RV = ~2300 mL.
- Vital Capacity (VC): TV + IRV + ERV = ~4600 mL.
- Total Lung Capacity (TLC): TV + IRV + ERV + RV = ~5800 mL.
What is dead space, and what are its types?
- Definition: Part of the respiratory system where no gas exchange occurs.
- Types:
- Anatomical dead space: Upper respiratory tract and conducting zone (~150 mL).
- Physiological dead space: Anatomical dead space + alveolar dead space (non-functioning alveoli).
- Significance: In diseased lungs, physiological dead space > anatomical dead space.
What is pulmonary ventilation, and how is it calculated?
- Definition: Volume of air flowing into and out of the respiratory tract per minute.
- Calculation:
- At rest: TV (500 mL) x Respiratory rate (12/min) = 6 L/min.
- During exercise: Can reach up to 120 L/min.
What is alveolar ventilation, and how is it calculated?
- Definition: Volume of air reaching the alveoli and undergoing gas exchange per minute.
- Calculation:
- Alveolar Ventilation (VA): (TV - Dead Space) x Respiratory Rate.
- Example: (500 mL - 150 mL) x 12/min = 4.2 L/min.
How do obstructive and restrictive lung diseases differ in spirometry findings?
- Obstructive Diseases:
- FEV1/FVC ratio: Decreased (<75%).
- Example: Asthma, emphysema.
- Restrictive Diseases:
- FEV1/FVC ratio: Normal or increased.
- Example: Pulmonary fibrosis.
What is the alveolar ventilation equation, and what does it show?
- Equation: VA = (VCO₂ / PACO₂) x constant.
- Significance: Alveolar ventilation is directly proportional to CO₂ production and inversely proportional to alveolar CO₂ pressure (PACO₂).
What are the effects of hypoventilation and hyperventilation on alveolar CO₂?
- Hypoventilation: Decreases alveolar ventilation, increases PACO₂.
- Hyperventilation: Increases alveolar ventilation, decreases PACO₂.
What are the key spirometry findings in obstructive and restrictive lung diseases?
- Obstructive:
- ↓ FEV1/FVC ratio.
- Air trapping → ↑ RV, FRC, TLC.
- Restrictive:
- Normal or ↑ FEV1/FVC ratio.
- ↓ TLC, FVC, FEV1.
What is timed vital capacity, and why is it important?
- Definition: Volume of air forcibly exhaled after maximal inspiration as fast and hard as possible.
- Importance:
- FEV1: Volume exhaled in the first second.
- FVC: Total volume exhaled.
- FEV1/FVC ratio: Helps distinguish obstructive from restrictive lung diseases.
What is residual volume, and why is it significant?
- Definition: Volume of air remaining in the lungs after maximal expiration.
What are the primary functions of the respiratory system?
- Removal of CO₂ from tissues → blood → air.
- Supply of O₂ to tissues: air → blood → cells.
- Pulmonary ventilation: inflow and outflow of air between the atmosphere and lungs.
- Gas exchange between lung alveoli and blood.
- Gas transport in blood.
- Cellular respiration: Utilization of O₂ by cells (mitochondria) to generate energy (ATP) and produce CO₂.
What are the functions of the upper respiratory passages?
- Air conditioning: Warming, humidification, cleaning, and filtering air (particles >2μm stick to mucous and are repelled by cilia).
- Pharynx: Common passage for air and food. During swallowing, respiration is inhibited, and air passages are protected.
What are the two zones of the lower respiratory passages, and what are their functions?
- Conducting zone (Generations 1-16):
- Trachea, bronchi, bronchioles.
- Function: Conduct air to the respiratory zone.
- Respiratory zone (Generations 17-23):
- Respiratory bronchioles, alveolar ducts, alveolar sacs (alveoli).
- Function: Gas exchange occurs here.
How does the structure of airways change from the trachea to the bronchioles?
- Trachea and bronchi: Contain cartilage to prevent collapse.
- Bronchioles: No cartilage, kept open by elastic tension of alveolar walls.
- Smooth muscle: Present in all airways except alveoli.
- Parasympathetic stimulation: Bronchoconstriction.
- Sympathetic stimulation: Bronchodilation.
What is the relationship between the lungs, chest wall, and pleura?
- Pleura: Each lung is surrounded by a pleural sac with two layers:
- Visceral pleura: Covers the lung.
- Parietal pleura: Lines the chest wall.
- Pleural fluid: Lubricates and allows lungs to slide over the chest wall during breathing.
- Excess fluid: Pleural effusion can lead to lung collapse.
What are the phases of the normal respiratory cycle?
- Inspiration (1.3 sec): Active process, air flows into the lungs.
- Expiration (1.7 sec): Passive process, air flows out of the lungs.
- Expiratory pause (1 sec): Brief pause before the next cycle.
- Respiratory rate: 12-18 breaths/min in adults, 30-40/min in infants.
What are the steps involved in the mechanics of breathing?
- Thoracic cage changes size: Ribs and diaphragm move.
- Lung size changes: Due to connection to the chest wall via pleura.
- Pressure gradient: Created between alveoli and atmospheric air.
- Airflow: Air moves in or out of the lungs.
What muscles are involved in inspiration, and what are their roles?
- Diaphragm: Responsible for 75% of resting inspiratory activity.
- Contracts and descends, increasing the vertical diameter of the thorax.
- External intercostals: Elevate and evert the ribs, increasing the transverse and anteroposterior diameter of the thorax.
What muscles are involved in forced breathing?
- Inspiration:
- Stronger contraction of diaphragm and external intercostals.
- Accessory muscles: Sternomastoid, serratus anterior, scalene muscles.
- Expiration:
- Internal intercostal muscles and abdominal wall muscles contract to force air out.
What are the four main lung volumes?
- Tidal Volume (TV): 500 mL, air inhaled/exhaled with each breath.
- Inspiratory Reserve Volume (IRV): 3000 mL, air inhaled during forced inspiration.
- Expiratory Reserve Volume (ERV): 1100 mL, air exhaled during forced expiration.
- Residual Volume (RV): 1200 mL, air remaining in the lungs after maximal expiration.
What are the four main lung capacities, and how are they calculated?
- Inspiratory Capacity (IC): TV + IRV = ~3500 mL.
- Functional Residual Capacity (FRC): ERV + RV = ~2300 mL.
- Vital Capacity (VC): TV + IRV + ERV = ~4600 mL.
- Total Lung Capacity (TLC): TV + IRV + ERV + RV = ~5800 mL.
What is dead space, and what are its types?
- Definition: Part of the respiratory system where no gas exchange occurs.
- Types:
- Anatomical dead space: Upper respiratory tract and conducting zone (~150 mL).
- Physiological dead space: Anatomical dead space + alveolar dead space (non-functioning alveoli).
- Significance: In diseased lungs, physiological dead space > anatomical dead space.
What is pulmonary ventilation, and how is it calculated?
- Definition: Volume of air flowing into and out of the respiratory tract per minute.
- Calculation:
- At rest: TV (500 mL) x Respiratory rate (12/min) = 6 L/min.
- During exercise: Can reach up to 120 L/min.
What is alveolar ventilation, and how is it calculated?
- Definition: Volume of air reaching the alveoli and undergoing gas exchange per minute.
- Calculation:
- Alveolar Ventilation (VA): (TV - Dead Space) x Respiratory Rate.
- Example: (500 mL - 150 mL) x 12/min = 4.2 L/min.
How do obstructive and restrictive lung diseases differ in spirometry findings?
- Obstructive Diseases:
- FEV1/FVC ratio: Decreased (<75%).
- Example: Asthma, emphysema.
- Restrictive Diseases:
- FEV1/FVC ratio: Normal or increased.
- Example: Pulmonary fibrosis.
What is the alveolar ventilation equation, and what does it show?
- Equation: VA = (VCO₂ / PACO₂) x constant.
- Significance: Alveolar ventilation is directly proportional to CO₂ production and inversely proportional to alveolar CO₂ pressure (PACO₂).
What are the effects of hypoventilation and hyperventilation on alveolar CO₂?
- Hypoventilation: Decreases alveolar ventilation, increases PACO₂.
- Hyperventilation: Increases alveolar ventilation, decreases PACO₂.
What are the key spirometry findings in obstructive and restrictive lung diseases?
- Obstructive:
- ↓ FEV1/FVC ratio.
- Air trapping → ↑ RV, FRC, TLC.
- Restrictive:
- Normal or ↑ FEV1/FVC ratio.
- ↓ TLC, FVC, FEV1.
What is timed vital capacity, and why is it important?
- Definition: Volume of air forcibly exhaled after maximal inspiration as fast and hard as possible.
- Importance:
- FEV1: Volume exhaled in the first second.
- FVC: Total volume exhaled.
- FEV1/FVC ratio: Helps distinguish obstructive from restrictive lung diseases.
What is residual volume, and why is it significant?
- Definition: Volume of air remaining in the lungs after maximal expiration.
