Overview
This lecture introduces the structure and main functions of the respiratory system, focusing on the anatomy of the upper and lower respiratory tracts, and the mechanics of breathing.
Respiratory System Overview
- The respiratory system is responsible for gas exchange—bringing in oxygen and removing carbon dioxide.
- It consists of two main parts: the upper and lower respiratory tracts.
Anatomy of the Upper Respiratory Tract
- The upper respiratory tract includes the nose, nasal cavity, pharynx (throat), and associated structures.
- The nose filters, warms, and moistens incoming air.
- The pharynx serves as a passageway for both air and food.
Anatomy of the Lower Respiratory Tract
- The lower respiratory tract includes the larynx (voice box), trachea (windpipe), bronchi, bronchioles, and lungs.
- The larynx routes air and contains the vocal cords for sound production.
- The trachea divides into right and left primary bronchi, leading to each lung.
- Bronchi branch into smaller bronchioles, ending in alveoli where gas exchange occurs.
Mechanics of Breathing
- Breathing involves two phases: inspiration (inhaling) and expiration (exhaling).
- Diaphragm contraction increases thoracic cavity volume, causing air to flow into the lungs.
- Relaxation of the diaphragm and intercostal muscles reduces thoracic volume and forces air out.
Key Terms & Definitions
- Pharynx — muscular tube that transports air and food; part of the upper respiratory tract.
- Larynx — organ containing vocal cords; routes air into the trachea.
- Trachea — windpipe; main airway leading from larynx to bronchi.
- Bronchi — two primary airways branching from trachea into lungs.
- Bronchioles — smaller airways branching from bronchi, ending at alveoli.
- Alveoli — tiny air sacs in lungs where gas exchange occurs.
- Diaphragm — dome-shaped muscle that assists in breathing by changing thoracic cavity volume.
Action Items / Next Steps
- Review diagrams of upper and lower respiratory tract anatomy.
- Read textbook sections on respiratory physiology for deeper understanding.