Overview
This lecture introduces the structures of the human respiratory system, focusing on the upper respiratory tract and its functions in breathing and protection.
Respiratory System Structures
- The respiratory system includes the nostrils, nasal cavity, pharynx, larynx, trachea, bronchi, lungs, and diaphragm.
- Breathing happens unconsciously due to the coordinated function of these structures.
Upper Respiratory System
- The upper respiratory system consists of the nostrils, nasal cavity, pharynx, and larynx.
- Nostrils are the openings for air entry into the body.
- Air passes from the nostrils into the nasal cavity, which is directly behind the nostrils.
- Tiny hairs and mucus in the nostrils trap dust, microorganisms, and particles, preventing them from entering the body.
- The nasal cavity warms the air as it enters.
- From the nasal cavity, air passes into the pharynx (top part of the throat, behind the nasal cavity).
- The pharynx is a common passageway for both food and air.
Protective Mechanisms
- The epiglottis is a flap-like structure that closes the trachea during swallowing to prevent food from entering the airway.
- This prevents airway blockage and possible breathing problems.
Larynx (Voice Box)
- The larynx is located below the pharynx and is also called the voice box.
- It contains vocal cords that vibrate to produce sound when their muscles contract and relax.
- The larynx allows speaking, singing, and other vocal sounds.
Key Terms & Definitions
- Nostrils — Openings in the nose for air intake.
- Nasal Cavity — Passage behind the nostrils where air is warmed and filtered.
- Pharynx — Throat region serving as a passage for both air and food.
- Epiglottis — Flap that prevents food from entering the trachea during swallowing.
- Larynx (Voice Box) — Structure containing vocal cords, enabling sound production.
Action Items / Next Steps
- Review the functions and roles of each upper respiratory structure.
- Prepare for the next lecture on the lower respiratory system (trachea, bronchi, lungs, alveoli, diaphragm).