Respiratory System- Clin Phys 4 Quiz

Respiratory System Structures and Functions

• The larynx contains the vocal folds, essential for sound production.
• The alveoli are the main site of gas exchange in the respiratory system, facilitating oxygen and carbon dioxide exchange.
• The conducting zone of the respiratory system is driven by pressure gradients for gas movement, allowing air to flow into the lungs.
• The bronchioles lack cartilage and are surrounded by smooth muscle, enabling variable airflow through constriction and dilation.
• The alveolar sacs are closely associated with pulmonary microvasculature, enhancing gas exchange efficiency.

Breathing Mechanics

• Diaphragm and intercostal muscles are primarily responsible for changing the volume of the thoracic cavity during breathing.
• The volume of the conducting airways, from the nasopharynx to the terminal bronchiole, is approximately 150 mL.
• The respiratory zone is driven by concentration gradients for gas movement, allowing gas to diffuse in and out of blood.
• Lung volume after a quiet inspiration is about 500 mL, known as the tidal volume.

Lung Anatomy and Pathology

• Alveoli occupy the majority of lung volume, maximizing surface area for gas exchange.
• During inspiration, intrathoracic pressure decreases, allowing air to flow into the lungs.
• The lower lobe of the lung is located deep to the posterior thorax, crucial for lung function.
• Pleural effusion results in fluid accumulation in the pleural cavity, potentially affecting breathing efficiency.

Expiration and Pressure Changes

• Abdominal and intercostal muscles primarily relax during expiration, allowing passive airflow out of the lungs.
• Intrathoracic pressure increases during expiration, driving air out of the lungs.

Nasal Cavity Function

• The nasal cavity warms, humidifies, and filters inhaled air, playing a vital role in respiratory health.

Pulmonary Disease Consequences

• Pleural effusion makes it difficult to hear breath sounds and causes dullness to percussion.
• Consolidation from pneumonia transmits sound better than air in the airspaces, leading to enhanced vocal resonance.
• Coarse crackles and decreased breath sounds are typical in pulmonary diseases like pneumonia.
• Fine crackles are associated with pulmonary edema due to infection or congestive heart failure.
• Wheezing, a high-pitched musical sound during expiration, is common in obstructive diseases like asthma and COPD.
• Loud, harsh sounds on inspiration occur with upper airway obstruction due to pulmonary disease.
• Diminished airspace expansion can result from various respiratory conditions.

Other Notable Conditions and Associations

• Unilateral pleural effusion may be caused by conditions such as infections, malignancies, or trauma.
• COPD is commonly associated with chronic bronchitis and emphysema.
• Asthma is often triggered by allergens and exercise-induced bronchoconstriction.
• In cases of an upper airway obstruction, stridor is typically heard.
• Bronchophony is a sign indicating lung consolidation or fluid in the lungs, often associated with pneumonia or lung disease.