Respiratory System Concepts

Alveolar Macrophages: Immune cells located in the alveoli that engulf and digest pathogens, debris, and dead cells, playing a crucial role in lung defense.

Anatomic Dead Space: Part of the respiratory system (trachea and bronchi) where gas exchange does not occur.

Atelectasis: Collapse or complete loss of part of a lung, leading to reduced gas exchange.

Bronchitis: Inflammation of the bronchial tubes, causing coughing, mucus production, and difficulty breathing.

Cartilage: A firm, flexible connective tissue found in the main, lobar, and segmental bronchi.

Chemoreceptors: Sensors that detect changes in chemical composition in the blood, influencing breathing rate.

Emphysema: A chronic lung disease characterized by the destruction of alveolar walls and loss of lung elasticity.

FEV1 (Forced Expiratory Volume in 1 second): Volume of air exhaled during the first second of a forced expiration.

FVC (Forced Vital Capacity): Total volume of air exhaled during a forced expiration.

Oxygen Reserve: Amount of oxygen bound to hemoglobin available for tissue use during increased demand.

Pneumothorax: Condition where air enters the pleural space, potentially causing lung collapse.

Surfactant: Substance secreted by Type 2 epithelial cells that reduces surface tension in the alveoli and prevents collapse.

Tidal Volume: Volume of air inhaled or exhaled during normal breathing, approximately 500 mL.

Vital Capacity (VC): Total volume of air that can be exhaled after a deep breath, typically about 4800 mL.

Main Bronchi: Two primary branches from the trachea (one for each lung).

Lobar Bronchi: Secondary branches serving each lung lobe; three in the right lung and two in the left.

Segmental Bronchi: Tertiary branches serving specific bronchopulmonary segments; ten in the right lung and eight in the left.

Subsegmental Bronchi: Smaller branches beyond the segmental bronchi.

Respiratory Zone: Region where gas exchange occurs, starting from the respiratory bronchioles.

Conduction Zone: Air passageways leading to the respiratory zone ending at the terminal bronchiole.

Alveolar Pores: Openings between alveoli that facilitate air movement and pressure equalization.

Intrapleural Pressure: Negative pressure in the pleural cavity essential for lung inflation.

Intrapulmonary Pressure: Pressure within the lung alveoli.

Pneumothorax and Atelectasis: Conditions resulting from disrupted pressures, leading to lung collapse.

Tidal Volume: Average air volume during normal breath.

Inspiratory Reserve Volume (IRV): Excess air inhaled beyond tidal volume.

Expiratory Reserve Volume (ERV): Excess air exhaled beyond tidal volume.

Total Lung Capacity (TLC): Maximum air volume the lungs can hold.

CO2 Transport: Occurs via three forms (dissolved, bound to hemoglobin, as bicarbonate ions).

O2 Movement and Hemoglobin Saturation: Influenced by partial pressure of O2, particularly at high elevations causing potential hypoxia.

Central Chemoreceptors: Located in the medulla, these regulate breathing based on blood CO2 and pH levels.

Bronchitis vs. Asthma: Bronchitis is caused by inflammation and infection; asthma is a chronic disorder triggered by allergens.

Emphysema: Results in loss of alveolar structure and difficulty in breathing.

Tidal Volume: Approximately 500 mL.

Inspiratory Reserve Volume (IRV): Approximately 3000 mL.

Expiratory Reserve Volume (ERV): Approximately 1200 mL.

Total Lung Capacity (TLC): Approximately 6000 mL.

Vital Capacity (VC): Approximately 4800 mL.

Partial Pressure Gas Movement: Gases move from higher to lower partial pressures, influencing O2 and CO2 exchange.

Alveolar Ventilation: Not an explicit formula provided, but typically measured as:

Gas Exchange Principle: Diffusion of gases occurs according to partial pressure gradients.

Assessment of Lung Function: Utilizes FEV1/FVC ratio to evaluate respiratory performance.