Respiratory Gases and Control

Respiratory Gases and Control

• Hypercapnia is high carbon dioxide concentration in body fluids.
• Arterial blood oxygen partial pressure (PO2) is typically 100 mm Hg.
• Carbon dioxide partial pressure (PCO2) in peripheral tissues is around 45 mmHg.
• Concentration gradient is a crucial factor determining respiratory gas diffusion.
• Diffusion exchanges dissolved gases between blood and interstitial fluids.
• Pulmonary edema, a lung condition, can stem from certain heart diseases.
• Fluid buildup in alveoli, leading to hypoxia, can cause adult respiratory distress syndrome (ARDS), which isn't corrected by oxygen therapy.
• At a PO2 of 70 mm Hg, normal temperature, and pH, hemoglobin is over 90% saturated with oxygen.
• Factors that shift the oxygen-hemoglobin curve to the right include increased CO2, temperature, decreased pH, and increased H+ ion concentration.
• Chronic hypoxia elevates 2,3-DPG production in the blood, potentially arising from anemia.
• Most blood carbon dioxide is transported as bicarbonate ions.

Respiratory Control Centers and Mechanisms

• The nucleus tractus solitarius in the medulla oblongata houses the dorsal respiratory group of neurons.
• Carbon dioxide is the primary chemical regulator of respiration.
• Increased blood carbon dioxide levels lead to increased breathing rate.
• Expiratory neurons control abdominal and internal intercostal muscles, while inspiratory neurons control the diaphragm and external intercostal muscles.
• The Hering-Breuer reflex prevents lung overexpansion.
• Protective lung reflexes include coughing and bronchoconstriction.