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Explore the processes, mechanisms, and disorders of respiration. Learn about ventilation, gas transport, respiratory volumes, lung capacities, and more. Understand the role of the respiratory system in maintaining acid-base balance.
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Exercise 40 Respiratory Physiology
Processes of respiration • Pulmonary ventilation • External respiration • Transport of respiratory gases • Internal respiration or cellular respiration
Mechanisms of respiration • Pulmonary ventilation • Inspiration • Expiration • Respiratory muscles • Diaphragm • External intercostal • Others
Mechanisms of respiration • Steps of ventilation • Contraction of diaphragm and external intercostal muscles • Increase of thoracic volume • Expansion of the pleural cavities and lungs • Decrease of lung pressure below atmospheric pressure
Mechanisms of respiration • Inspiration • Lung pressure becomes equal to atmospheric pressure • Air stops to flow inside • Relaxation of respiratory muscles • Recoiling of the lung tissue
Mechanisms of respiration • Decrease of intrathoracic and intrapulmonary volumes • Increase of pulmonary pressure • Expiration
Mechanisms of respiration • Pneumothorax it is the entry of air into the pleural cavity • It breaks the fluid bond between the visceral and parietal pleura • It will cause the lung to collapse – atelectasis
Respiratory volumes and capacities • Spirometry • Tidal volume (TV) • It is the amount of air inspired or expired with each breath under resting conditions • 500 ml
Respiratory volumes and capacities • Inspiratory reserve volume (IRV) • It is the amount of air that can be forcefully inspired after a normal tidal inspiration • 3100 ml
Respiratory volumes and capacities • Expiratory reserve volume (ERV) • It is the amount of air that can be forcefully expired after a normal tidal expiration • 1200 ml • It is reduced in conditions in which the elasticity of the lungs is decreased
Respiratory volumes and capacities • Vital capacity (VC) • It is the maximum amount of air that can be expired after a maximal inspiration • 4800 ml • VC = TV + IRV + ERV
Respiratory volumes and capacities • Residual volume (RV) • It is the amount of air that remains in the lung after a ERV • 1200 ml
Respiratory volumes and capacities • Functional residual capacity (FRC) • It is the amount of air that remains in the lung after a quiet respiratory cycle • 2400 ml • FRC = ERV+RV
Respiratory volumes and capacities • Total lung capacity (TLC) • It is the total volume of the lungs • 6000 ml • TLC = VC+RV
Respiratory volumes and capacities • Nonrecording spirometer • Handheld dry spirometer • Measures only expired air • Wet spirometer • Measures only expired air • Recording spirometer • Measures inspired and expired air
Pulmonary disorders • Obstructive • Bronchitis • Asthma • Restrictive • Tuberculosis • Poliomyelitis
Respiratory volumes and capacities • Forced vital capacity (FVC) • It is the amount of air expired after a deep inspiration and a forced and quick expiration • Reduced in restrictive pulmonary diseases
Respiratory volumes and capacities • Forced expiratory volume measurement (FEV1%) • It is the percentage of vital capacity that is exhaled during specific intervals of time • It is reduced in obstructive diseases
Respiratory rate and depth • Factors that changes the RR • Exercise • Coughing • Walking • Talking • Laughing, etc
Respiratory sounds • Bronchial sounds • Heard below the larynx • Vesicular sounds • Air filling the alveolar sacs • Heard over the chest • Crepitation (crackles) • Wheezing – a whistling sound
Role of respiratory system in acid-base balance of blood • Blood pH • 7.35-7.45 • Carbonic acid-bicarbonate buffer • The main body buffer
Acid-base imbalance • Alkalosis • Blood pH above 7.45 • Respiratory or metabolic • Acidosis • Blood pH bellow 7.35 • Respiratory or metabolic