Respiratory System Overview

Respiratory System I & II

• Primary function: Supply the body with oxygen and remove carbon dioxide.

Respiratory Processes

• Pulmonary ventilation: Movement of air into and out of the lungs.
• External respiration: Gas exchange between alveoli and blood (oxygen enters blood, carbon dioxide leaves).
• Transport of gases: Oxygen and carbon dioxide transport in the blood between lungs and body tissues.
• Internal respiration: Gas exchange between blood in systemic capillaries and tissue cells (oxygen diffuses in, carbon dioxide diffuses out).

Cellular Respiration's Role

• Cells use oxygen to convert glucose to ATP (energy).
• Carbon dioxide is a byproduct, removed by the respiratory system.

Respiratory Zone vs. Conducting Zone

• Respiratory zone: Site of gas exchange (alveoli).
• Conducting zone: Pathway for air to reach respiratory zone (filters, warms, humidifies air).

Nose Functions

• Airway
• Filters and moistens air
• Warms air
• Resonating chamber for speech
• Houses olfactory receptors

Nasal Cavity Filtering

• Mucus lining traps particles.
• Ciliated cells move mucus to throat.
• Capillaries warm air.

Pharynx Regions

• Nasopharynx: Air passageway (closes during swallowing).
• Oropharynx: Food and air passageway (lined with protective epithelium).
• Laryngopharynx: Directs food and air to correct channels (continuous with esophagus).

Larynx Structure & Function

• Connects pharynx to trachea.
• Open airway.
• Food and air passageway.
• Houses vocal cords (speech).

Trachea & Bronchi Structure

• Hyaline cartilage rings in trachea prevent collapse.
• Bronchi branches have cartilage plates, decrease as airways narrow.

Alveolar Ventilation

• Amount of air entering alveoli per minute.
• Essential for adequate gas exchange, fresh oxygen delivery, and carbon dioxide removal.

Intrapulmonary Pressure vs. Atmospheric Pressure

• Inhalation: Intrapulmonary pressure drops below atmospheric pressure, drawing air into lungs.
• Exhalation: Intrapulmonary pressure rises above atmospheric pressure, pushing air out of lungs.

Intrapleural Pressure

• Always negative relative to intrapulmonary pressure.
• Maintains lung inflation by keeping lungs adhered to thoracic wall (expands and recoils with breathing).

Surfactant Function

• Produced by type II alveolar cells.
• Reduces surface tension in alveoli, preventing collapse during exhalation.

Lung Volumes

• Tidal volume: Air moved in/out with normal breath.
• Inspiratory reserve volume: Extra air inhaled beyond tidal volume.
• Expiratory reserve volume: Extra air exhaled beyond tidal volume.
• Residual volume: Air remaining in lungs after maximum exhalation.
• Vital capacity: Sum of tidal volume, inspiratory reserve volume, and expiratory reserve volume (maximum exhalation followed by maximum inhalation).

Hypoventilation & Hyperventilation

• Hypoventilation: Insufficient alveolar ventilation, low oxygen and high carbon dioxide, hypoxemia.
• Hyperventilation: Excessive alveolar ventilation, increased oxygen and reduced carbon dioxide, respiratory alkalosis.

Partial Pressure Gradients

• Oxygen and carbon dioxide move down their partial pressure gradients across respiratory membrane.

Hemoglobin Role in Oxygen Transport

• Hemoglobin carries most oxygen in blood.
• Affected by temperature and pH (lower pH and higher temperature reduces hemoglobin's affinity for oxygen, facilitating release to tissues—Bohr effect).

Medullary Respiratory Centre

• Regulates breathing rhythm.
• Controlled by levels of carbon dioxide, oxygen, pH, and peripheral and central chemoreceptors.

This quiz covers the essential functions and processes of the respiratory system, including pulmonary ventilation, external and internal respiration, and the differences between the respiratory and conducting zones. Understand how the body utilizes oxygen and removes carbon dioxide during cellular respiration.