Respiration Systems and Breathing Patterns

Respiration

• The respiratory system has three primary functions: supplying oxygen (O₂), removing carbon dioxide (CO₂), and regulating blood acidity (pH).
• These functions work closely with the circulatory system.
• Respiration is a cyclical process of inhalation and exhalation (Fig 5.1).
• The upper respiratory system prepares the air (filtering, warming, increasing humidity).
• The lower respiratory system (trachea, bronchial tubes) is the pathway to the lungs (Fig 5.2).
• Inspiration occurs when external intercostal muscles and the diaphragm contract, increasing the thoracic cavity volume and lowering air pressure in the lungs (Fig 5.2, left).
• Expiration happens when these muscles relax, decreasing thoracic cavity volume and increasing air pressure, forcing air out of the lungs (Fig 5.2, right).

Breathing Patterns

• Normal breathing (Eupnea) is a regular pattern (Fig 5.1).
• Irregular breathing during speaking, (Fig 5.3) can occur.
• Hyperventilation (Fig 5.4) is increased breathing rate/depth, lowering blood CO₂ and raising pH (alkaline).
• Hypoventilation (Fig 5.5) is decreased breathing rate/depth, raising blood CO₂ and lowering pH (acidic).

Measuring Respiration

• Pneumograph transducers (strain gauges) measure chest expansion/contraction, determining respiratory rate (Fig 5.6).
• Spirometry and breath gas analysis measure inhaled/exhaled air volume and composition. (Fig 5.6).
• The Biopac system (Fig 5.6) can measure respiratory activity.
• Devices like the POWERbreathe 5 (Fig 5.7) measure respiratory resistance.

Factors Influencing Respiration

• Respiratory centers in the medulla and pons control breathing under normal conditions.
• Chemoreceptors (measuring CO₂ and H⁺ in blood), lung stretch receptors, and other sensory receptors provide input to these centers.
• Autonomic reflexes also influence respiration.
• Voluntary control over breathing is possible, impacting consciousness and other psychological states (such as meditation).
• Breathing patterns can change during speech, emotions, stress, and social interaction.