1. Nasal Cavity:
* External Nares (Nostrils): Openings where air enters the respiratory system.
* Nasal Septum: Divides the nasal cavity into two chambers.
* Nasal Conchae: Curved bony structures that create turbulence in the air flow, helping to warm, moisten, and filter the air.
* Olfactory Epithelium: Contains sensory receptors for smell.
2. Pharynx:
* Oropharynx: The portion of the pharynx that connects to the mouth.
* Nasopharynx: The portion of the pharynx that connects to the nasal cavity.
* Laryngopharynx: The portion of the pharynx that connects to the larynx.
3. Larynx (Voice Box):
* Epiglottis: A flap of cartilage that covers the opening of the larynx during swallowing, preventing food from entering the trachea.
* Vocal Cords: Two folds of tissue that vibrate to produce sound.
4. Trachea (Windpipe):
* C-Shaped Cartilaginous Rings: Support the trachea and prevent it from collapsing.
* Mucus-Secreting Cells: Line the trachea and trap dust and other particles.
5. Bronchi:
* Main (Primary) Bronchi: Two branches of the trachea that lead to each lung.
* Lobar (Secondary) Bronchi: Branches of the main bronchi that lead to the lobes of the lungs.
* Segmental (Tertiary) Bronchi: Branches of the lobar bronchi that lead to the bronchopulmonary segments.
6. Bronchioles:
* Terminal Bronchioles: Smallest airways in the lungs.
* Respiratory Bronchioles: Transition zone where gas exchange begins.
7. Alveoli:
* Tiny air sacs: Where gas exchange occurs.
* Alveolar Ducts: Connect alveoli to respiratory bronchioles.
* Capillaries: Tiny blood vessels that surround alveoli, allowing for diffusion of oxygen into the blood and carbon dioxide out of the blood.
Overall Pathway of Air:
1. External Nares (Nostrils)
2. Nasal Cavity
3. Nasopharynx
4. Oropharynx
5. Laryngopharynx
6. Larynx
7. Trachea
8. Main Bronchi
9. Lobar Bronchi
10. Segmental Bronchi
11. Bronchioles
12. Terminal Bronchioles
13. Respiratory Bronchioles
14. Alveolar Ducts
15. Alveoli
This intricate network of airways ensures that air can be efficiently transported to the alveoli, where the crucial exchange of oxygen and carbon dioxide takes place.