Air enters through the external nostrils (above the upper lips), passes into the nasal chamber, then the pharynx (a common passage for food and air), and then the larynx (the "sound box") before reaching the trachea. Memory hook: "Nose to Chamber to Throat to Box" = Nostrils, Nasal chamber, Pharynx, Larynx, in that exact order. For NEET, remember these parts belong to the conducting part, so they warm, moisten and clean the air but do NOT exchange gases.
The correct NEET sequence of the upper conducting airway: external nostrils to nasal chamber to pharynx (common passage for food and air) to larynx (sound box) to trachea. These parts warm, moisten and clean air but do not exchange gases.
Your doubts, answered
What is the correct order of parts from the nostrils to the trachea?
External nostrils to nasal chamber to pharynx to larynx to trachea. NCERT states it clearly: the external nostrils lead to a nasal chamber through the nasal passage, the nasal chamber opens into the pharynx, and the pharynx opens through the larynx region into the trachea. Learn this exact sequence because NEET often asks you to arrange these parts in order.
Is the pharynx part of the respiratory system or the digestive system?
Both. The pharynx is a common passage for food and air. NCERT says 'a portion of which is the common passage for food and air.' So air from the nasal chamber and food from the mouth both pass through the pharynx. This is why swallowing and breathing are carefully coordinated, so food goes to the food pipe and air goes to the larynx.
Why is the larynx called the sound box?
The larynx is a cartilaginous box that helps in sound production, so NCERT calls it the sound box. When air passes through it, the larynx can produce sound (voice). It is the last part before the trachea. Note: the detailed role of the epiglottis in swallowing is covered on the next concept page.
Does the nasal chamber take part in gas exchange?
No. The nasal chamber, pharynx and larynx are all part of the conducting part of the respiratory system. The conducting part only transports air to the alveoli, cleans it of foreign particles, humidifies (moistens) it, and brings it to body temperature. Actual exchange of O2 and CO2 happens only in the alveoli (the exchange or respiratory part), not here.
Where exactly do the external nostrils open?
NCERT states we have a pair of external nostrils opening out above the upper lips. From there air moves through the nasal passage into the nasal chamber. A common NEET trap is the word 'pair' (two nostrils) and the location 'above the upper lips' - remember both facts.
⚠️ The NEET trap ✗ Air goes nostrils to larynx to pharynx to trachea (larynx before pharynx). ✓ Air goes nostrils to nasal chamber to pharynx to larynx to trachea. The pharynx comes BEFORE the larynx; the pharynx opens through the larynx region into the trachea. 🧠 Read the pathway word-for-word from NCERT, do not add extra parts.
Real NEET questions
2022
Which of the following is not the function of the conducting part of the respiratory system?
A · It clears inhaled air from foreign particles
B · Inhaled air is humidified
C · Temperature of inhaled air is brought to body temperature
D · Provides surface for diffusion of O2 and CO2 ✓
Solution: The conducting part (external nostrils up to the terminal bronchioles, including nasal chamber, pharynx and larynx) transports air to the alveoli, clears it of foreign particles, humidifies it and brings it to body temperature. Actual diffusion of O2 and CO2 happens only in the exchange part (alveoli), not the conducting part. So option (D) is NOT a function of the conducting part. NCERT Ch 14, p.185.
Solved Breathing and Exchange of Gases NEET PYQs
Try the real previous-year questions from this chapter — each with the answer and a full solution.
