Problem 25 - Objective Biology for NEET

Question

Which of the following acts as a common passage for food and air? (a) Larynx (b) Pharynx (c) Oesophagus (d) Glottis

Step-by-Step Solution

Answer

The Pharynx (b) acts as a common passage for both food and air.

Step 1: Analyzing the options

Start by assessing the functions of each of the options; Larynx, which is responsible for breathing, sound production and food aspiration prevention. Pharynx is behind the mouth and nasal cavity and common to both the respiratory and digestive system. On the other hand, the oesophagus strictly carries food from pharynx to the stomach, and glottis is part of the larynx responsible for voice modulation.

Step 2: Picking the common passage for food and air

Among the options, the one that acts as a common passage for both food and air is the Pharynx. This is because it is shared by both the digestive and respiratory system.

Key Concepts

Digestive System

The digestive system is a complex and essential part of the human body that is responsible for breaking down the food we eat into nutrients, which the body uses for energy, growth, and cell repair. It starts at the mouth, where food is ingested, and includes a series of organs connected in a long, twisting tube from the mouth to the anus: the pharynx, esophagus, stomach, intestines, and more.
The primary function is to convert food into small, absorbable molecules that can enter the bloodstream. Enzymes play a crucial role in this process, catalyzing the breakdown of different food components. In the context of the pharynx, this part of the system is an initial passage where both food and air pass before branching into separate pathways for digestion and respiration.

• The mouth starts the digestion with chewing and saliva secretion.
• Food then moves to the pharynx, a cooperative area with the respiratory system.
• From the pharynx, food enters the esophagus and progresses towards the stomach.

Respiratory System

The respiratory system is crucial for breathing and consists of organs responsible for taking in oxygen and expelling carbon dioxide. It includes the nose, nasal cavity, pharynx, larynx, trachea, bronchi, and lungs. The process starts when you inhale air through your nose or mouth, which then travels through the pharynx before proceeding to the lower respiratory tract.
In the pharynx, air finds its path separate from food by moving into the larynx and down the trachea towards the lungs. The respiratory system functions efficiently to ensure that oxygen reaches every part of the body, while carbon dioxide is expelled as a waste product.

• The nose and nasal cavity filter, warm, and moisturize the air.
• Air then passes through the pharynx, which acts as a junction with the digestive system.
• Finally, air travels through the larynx and into the lungs.

Common Passage for Food and Air

The pharynx serves as a vital anatomical intersection between the digestive and respiratory systems, acting as a common passage for both food and air. This shared pathway includes regions that handle distinct tasks before directing substances into the appropriate routes.
In this shared passageway, food must be kept out of the airway to prevent choking or aspiration. The body manages this through a flap known as the epiglottis, which closes off the trachea during swallowing so that food safely proceeds down the esophagus.

• Pharynx connects to the nasal cavity and mouth, sharing functions related to breathing and digestion.
• It has specialized regions – the nasopharynx for air, and the oropharynx and laryngopharynx for both air and food.
• Correct functioning of the pharynx and epiglottis prevents food from entering the airway during swallowing.