Problem 162 - Objective Biology for NEET

Question

Assertion: Pharynx serves as common passage for air and food Reason: Trachea and oesophagus open into pharynx

Step-by-Step Solution

Answer

Yes, the assertion and the reason are correct. The Pharynx does serve as a common passage for air and food, and this is because both the Trachea and the Oesophagus open into it.

Step 1 Understanding the Anatomy

Begin by understanding the interconnected structure of the Pharynx, Trachea, and Oesophagus. The Pharynx is part of the digestive and respiratory systems; it's a funnel-shaped tube that connects the nasal and oral cavities to the Esophagus and Trachea respectively, hence serving as a common passage for both air and food.

Step 2 Analyzing the Function of Trachea and Oesophagus

Next, understand the role of each part. The Trachea, or windpipe, is the tube through which air is transported to and from the lungs. The Oesophagus, on the other hand, is the tube that connects the Pharynx to the stomach, through which food and liquid are transported.

Step 3 Connecting the Anatomy and Functions

Now that the functions of the Pharynx, Trachea, and Oesophagus are understood, it can be concluded that the Trachea and Oesophagus do open into the Pharynx. In other words, inhaled air and ingested foods or liquids pass through the Pharynx before reaching their respective channels, the Trachea or the Oesophagus.

Key Concepts

Trachea

The trachea, commonly known as the windpipe, plays a crucial role in the respiratory system. It acts as the main passageway for air to travel from the pharynx and larynx down into the lungs. This tube is about 10 to 12 centimeters long and is located just below the larynx, running down the midline of the neck.
The trachea is constructed of cartilage rings connected by muscle and connective tissue. These rings help maintain the trachea’s structure and prevent it from collapsing, even when there's less air pressure inside it.

• The trachea is lined with cilia and mucus that trap and expel foreign particles and pathogens.
• It divides into two bronchi which lead to each lung, facilitating efficient air delivery.

The efficient functioning of the trachea ensures that air reaches the lungs clean and moist, essential for healthy respiratory functioning.

Oesophagus

The oesophagus serves as a critical component of the digestive system. It is a muscular tube that conveys food and liquids from the pharynx to the stomach. Unlike the trachea, the oesophagus lacks the rigid cartilage rings, giving it a more flexible, muscular structure.
The oesophagus measures about 25 centimeters in length and is composed of several layers, including a tough outer layer and a muscular middle layer that helps propel food downward through peristaltic movements.

• Peristalsis involves coordinated muscle contractions that push food toward the stomach.
• A sphincter at the end prevents backflow of stomach contents.

This muscular coordination allows smooth transport of ingested materials, preventing choking and ensuring digestion continues efficiently.

Digestive and Respiratory Systems

Both the digestive and respiratory systems are vital for the body, and the pharynx serves as a common link between them. While the digestive system's primary purpose is to break down food to extract nutrients, the respiratory system focuses on exchanging oxygen and carbon dioxide.
The pharynx acts as a gateway where both systems converge. During swallowing, the epiglottis—a small flap of cartilage—closes over the trachea, preventing food from entering the respiratory pathways.

• The digestive system includes organs like the stomach, intestines, and liver, while the respiratory system encompasses the trachea, bronchi, and lungs.
• These systems collaborate to maintain body energy and facilitate cellular respiration.

By working together, these systems ensure food is efficiently digested and the body is adequately oxygenated.