As Nostrils, Windpipe, and lungs are part of respiratory system. And Gullet And mouth are not the parts of the respiratory system

Parts of the Human Respiratory System

The human respiratory system is responsible for the exchange of oxygen and carbon dioxide in the body. It consists of several organs and structures that work together to facilitate the process of breathing. Let's examine each option to determine which ones are parts of the respiratory system.

(i) Mouth:
The mouth is not directly involved in the respiratory system. It is primarily involved in activities such as eating, drinking, and speaking. However, during breathing, the mouth can be used as an alternative pathway for air intake when the nostrils are blocked.

(ii) Nostrils:
The nostrils, also known as the nasal passages, play a crucial role in the respiratory system. They are the primary entry points for air into the respiratory system. The nostrils are lined with tiny hairs and mucus-producing cells that help filter and humidify the incoming air, protecting the respiratory system from harmful particles and pathogens.

(iii) Gullet:
The gullet, also known as the esophagus, is not part of the respiratory system. It is a muscular tube that connects the mouth to the stomach and is involved in the process of swallowing food.

(iv) Windpipe:
The windpipe, also known as the trachea, is a vital component of the respiratory system. It is a tube-like structure that connects the larynx (voice box) to the bronchi. The windpipe allows air to pass from the upper respiratory tract to the lower respiratory tract, where gas exchange occurs.

(v) Lungs:
The lungs are the main organs of the respiratory system. They are responsible for the exchange of oxygen and carbon dioxide. The lungs are located in the chest cavity and are protected by the ribcage. They consist of numerous small air sacs called alveoli, where the exchange of gases between the blood and the air takes place.

Conclusion:
Based on the above analysis, the correct answer is option (b) (i), (ii), (iv), and (v) only. The mouth is not directly involved in the respiratory system, and the gullet is part of the digestive system rather than the respiratory system. The nostrils, windpipe, and lungs are all essential components of the human respiratory system.