The respiratory system is the vital system of the human body to remain alive. On this page, you will come to know how the respiratory system works.

The human body contains 100 trillion cells or units of life. Each living cell is a mass of protoplasm with a nucleus and it needs oxygen for its metabolic activities and to rid itself of carbon dioxide, by the process called respiration.

The human being is an air-breathing creature and takes oxygen from the atmosphere and exchanges it for carbon dioxide in the blood through the organization of the respiratory system.

The function of the distribution of food and oxygen is carried out by the cardiovascular system. Thus the respiratory system and circulatory system have closely integrated activities.

The blood receives food oxygen from the gastrointestinal and respiratory systems respectively and thus enriched it is circulated throughout the body by the cardio-vascular system ensuring adequate supply to all the body cells. 

The respiratory system is divided for descriptive purposes into the upper and lower respiratory tracts, the dividing line being the lower border of the Adam’s apple in the neck.

The upper respiratory system

The pyramid-shaped nose extends beyond into the nasal cavity and nasopharynx.

The mucus membrane is lined by ciliated epithelium and has a rich vascular supply. The inspired air is warmed by vascularity. Further, Cilia, aided by sticky mucus, trap foreign particles and propel them towards the pharynx. Cilia trap and remove particles and bacteria, moving them to the pharynx. Thus Cilia in the respiratory epithelium prevent infections. Every 20 minutes the nose produces a clean new mucus blanket.

The narrow openings that communicate the nasal sinuses with the nasal cavities are frequently involved in nasal and nasopharyngeal infections. Thus inflamed sinus openings hinder drainage, resulting in slow and incomplete infection resolution. 

The larynx produces voice and blocks large particles from entering the lower respiratory tract.

The larynx does it using the cough reflex. Cough can be a voluntary or reflexive response to irritation, mediated by the medulla. Further forceful exhalation with closed glottis followed by explosive air release along with sputum or irritating matter.

The lower respiratory tract

The trachea runs from the larynx to the lungs’ main lobes, where it branches into three lobes on the right and two on the left. Further, the bronchial tree divides into smaller and smaller tubes, ending in the terminal bronchioles. Each respiratory bronchiole communicates with a cluster of alveoli.

Alveoli are small sacs that are in direct contact with lung capillaries. Respiratory gases exchange between alveolar air and pulmonary capillary blood. Finally, blood carries oxygen and nutrients throughout the body via the cardiovascular system.

Summary

Oxygen is the need of body cells life. The respiratory system from the nose to the alveolus is the body’s window for oxygen. Microorganisms in the atmosphere can enter the body through the respiratory system. Hence, wear a nose and mouth mask to protect from exposure during the pandemic.

Although the cilia, mucus and our immune system trap these and protect the body against some of the infections.