MCAT Basics (from MedSchoolCoach) The Respiratory System
Jul 1, 2025
Dive into the intricacies of the respiratory system, exploring its anatomy and key functions like gas exchange and thermoregulation. Learn how air travels through the trachea to the alveoli and discover the role of pulmonary surfactant in preventing alveolar collapse. The dynamics of breathing are explained through Boyle's law, while the importance of pH control showcases the respiratory system's impact on blood. Also, hear about the neural controls that regulate our breathing patterns. An enlightening look at how we breathe!
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Upper vs Lower Respiratory Anatomy
- The respiratory tract splits into upper (nose, sinuses, larynx, trachea) and lower (bronchi, bronchioles, alveoli) regions important for function.
- Alveoli are tiny, thin-walled clusters where gas exchange occurs across capillaries.
Breathing Driven By Pressure Changes
- Diaphragm contraction increases chest volume, lowering intrapulmonary pressure to draw air in by Boyle's law.
- Exhalation reverses this as volume decreases and pressure rises, forcing air out toward lower atmospheric pressure.
Surfactant Prevents Alveolar Collapse
- Alveolar surface tension from water risks collapse, particularly in small alveoli per Laplace's law.
- Pulmonary surfactant (mostly phospholipids) reduces surface tension to prevent alveolar collapse.