Free online course Respiratory Physiology

About the free online course

Understanding how we breathe is essential for anyone studying health, medicine, sports science, or patient care. This free online course in respiratory physiology helps you build a clear, working model of the respiratory system, from airflow through the upper airways to oxygen delivery at the tissues. Instead of relying on memorization, you will connect structure to function and learn to predict what happens when normal physiology is altered by disease, exercise, or environmental stress.

You will explore the mechanics that move air in and out of the lungs, focusing on pressure changes, pleural fluid, and the muscle actions that expand the thoracic cavity. By linking airway anatomy to resistance and flow, you will see why small changes in airway radius can have outsized effects on ventilation. You will also examine surface tension in the alveoli and the crucial role of surfactant in keeping alveolar units open and efficient, then connect these ideas to lung compliance and the consequences of conditions that make the lungs stiffer.

The course also develops your ability to interpret foundational pulmonary measurements. You will make sense of lung volumes, tidal volume, and what spirometry reveals about ventilation patterns. From there, the focus expands to gas exchange: ventilation-perfusion coupling, diffusion across the respiratory membrane, and how thickness and partial pressure gradients shape oxygen and carbon dioxide transfer. You will understand why CO2 can equilibrate effectively despite different gradients and how internal respiration differs from external respiration.

To tie physiology to real-world situations, you will study types of hypoxia, the oxygen-hemoglobin dissociation curve, and what shifts in the curve indicate about temperature, pH, and metabolic demand. Finally, you will connect regulation of breathing to neural control, chemoreceptor responses to CO2, protective reflexes, and adaptations during exercise and at high altitude. With integrated practice questions throughout, you will reinforce concepts and gain confidence applying respiratory physiology to clinical and performance scenarios.