Human Organs-Lungs

So first of all let’s see lungs definition – Lungs are the central organ of the respiratory system. Every cell needs oxygen to be alive and healthy in the human body. It also needs carbon dioxide to be reduced. Therefore, lungs are designed to exchange harmful gases out of our body and suitable gases to enter the body. The lungs are the central part of the respiratory system, but the whole system is divided into two parts. The upper respiratory system starts from the nose, and the lower respiratory system starts from the lungs. 

Lungs definition and respiratory system 

Humans have pulmonary respiration. The respiratory system of humans includes a long respiratory tract, respiratory organs, and Lungs. The respiratory tract is a deeply placed passage into the Lungs that connect with the atmosphere. The fresh air from the atmosphere reaches into the Lungs and stands with CO2 coming out from the body. The respiratory tract includes a pair of nostrils, nasal cavity, internal nares, pharynx, larynx, trachea, and bronchioles. 

The Lungs are the principal organ of the respiratory system. It is located inside the thoracic cavity, which is a tight camber, bounded by the diaphragm on the lower side, ribs on the sites, and in front with sternum and thoracic vertebrae on the back. Lungs freely lie in the thoracic cavity. 

Lungs are enclosed in a pair of extremely thin double membrane sacs known as pleural sacs. The outer membrane of the pleural sac is known as the parietal pleura, and the inner membrane is known as the visceral pleura. The visceral pleura lies in contact with the Lungs. The pleural membrane is separated with a thin space called a pleural cavity. The cavity is filled with pleural fluid that provides frictionless movement to the Lungs. It also helps to avoid shocks and keep the Lungs moist. 

Structure and mechanism of Lungs

The Lungs had two layers, the internal layer and the external layer. The internal structure and outer structure of the Lungs have different functions and mechanisms. 

External structure

Lungs are soft, elastic, and spongy organs. From birth, the colour of the Lungs is pink, but eventually, it turns grey or darkened due to the deposition of pollutants. Each lung is subconical with a narrow apex, a broad concave semilunar base to accommodate the diaphragm next to ribs, and a concave median surface around the mediastinum.  

The primary bronchus and pulmonary blood vessels enter each lung through a slit on its medial surface known as the hilum. The lung located on the right is larger than the left lung and consists of three lobes, right upper, right middle , and right lower. The left lung has two lobes, left imperfect and left superior, desecrated by an oblique fissure. The lung situated on the left also has a cardiac notch that accommodates the heart. 

Internal structure 

Tertiary and secondary bronchioles: the bronchus on the right is divided into three secondary bronchi inside the right lung. The left bronchus divides into two secondary bronchi. Further, the secondary bronchi are divided into terminal bronchi. There are 10 types of tertiary bronchi in the right lung and 8 bronchi in the left lung. Cartilaginous rings also support the walls of these two bronchi. 

Bronchioles: each tertiary bronchus is divided into bronchioles. Each is 1 mm in diameter and divided into minute terminal bronchioles. This is further divided into respiratory bronchioles and terminal bronchioles. 

Atria, alveolar ducts, sacs, and alveoli: each respiratory bronchiole is divided into more delicate branches, which vary from 2 to 11 numbers. These alveolar ducts open into the alveolar sacs. Each sac is known as the atrium as well. It contains a passage in the centre with several small pouches, known as air sacs. These sacs are polyhedral in shape and are usually clustered together like a bunch of grapes. The air within the sacs can enter other sacs with tiny pores. The cluster of alveoli constitutes the functional units of the Lungs. There are over 300 hundred tiny alveoli in each human being. 

Respiratory membrane: the membranous wall of alveoli is called the respiratory membrane. On the outer surface of this wall, there is a dense network of blood capillaries. The blood in the veins is separated from the air in the alveoli only by two layers of cells, known as capillary endothelium and alveolar epithelium.

Different Lungs function in the human body. 

The lungs function in the human body to help us breathe. It brings oxygen into the human body and sends carbon dioxide out of the body. This process is known as inhalation and exhalation. The exchange of oxygen and carbon dioxide is known as respiration. 

Conclusion

The ling in the body helps us inhale oxygen and get rid of carbon dioxide and other bad air gases or air from our body. The lungs are an essential part of our body and the heart and brain. The nervous system also controls it. Sometimes lung function depends on our healthy lifestyle. For example, smoking causes issues in lungs and can block the cells and destroy their position.