Anatomy of the Lungs

The lungs are two spongy, air-filled organs that are positioned on each side of your chest (thorax) and the function of the lungs is very important. Your trachea (windpipe) transports breathed air to your lungs via tubular branches known as bronchi. The bronchi split further into increasingly smaller branches or bronchioles, eventually becoming tiny.

Bronchioles finally terminate in clusters of small air sacs known as alveoli. The oxygenated blood is taken into the blood by the alveoli. Carbon dioxide, a metabolic waste product, flows from the blood to the alveoli, where it is released. The interstitium is a delicate layer of cells that exists between the alveoli and comprises blood veins and cells that assist in sustaining the alveoli.

The lung is one of the two main units of respiration found inside the chest cavity and is essential for supplying oxygen to and eliminating carbon dioxide from the blood in air-breathing animals. Every lung in humans is covered in a thin membrane sac known as the pleura, and each is linked to the trachea (windpipe) via its primary bronchus (large air route) and the heart by the pulmonary arteries. The lungs are fragile, light, porous, flexible structures that always hold some air after conception. They will absorb moisture and clatter when squished if they are fit and active; infected lungs will plunge.

The hilum, located about two-thirds of the way from the base to the apex of each lung, is the place at which the bronchi, pulmonary arteries and veins, lymphatic vessels, and nerves join the lung. After reaching your lung, the primary bronchus splits several times, culminating in an overturned tree-like structure of tubules to maintain the function of the lungs. 

The sizes of the bronchi gradually decrease to less than 1 mm (0.04 inch). Bronchial tubes are branches 3 mm or less in diameter that connect to minute air sacs called alveoli wherein the real gas molecules of oxygen and carbon dioxide are transferred between your respiratory spaces and the blood capillaries.

Each lung is split into lobes that are separated by a tissue fissure. The right lung contains three primary lobes, whereas the left lung comprises two lobes due to the uneven positioning of your heart. Each lobe is further subdivided internally into hundreds of lobules. Each lobule has a bronchiole and connected branches, a shallow wall, and alveolar clusters.

The oropharynx, nose, larynx, bronchi, trachea, bronchioles, and lungs make up the majority of your respiratory system to maintain the function of the lungs. The lungs are further subdivided into separate lobes, which are further subdivided into more than 300 million alveoli. The principal site of the exchange of gases in the alveoli. The diaphragm is the major respiratory muscle and is innervated by the C3, C4, and C5 nerve roots via the phrenic nerve. External intercostals are inspiratory muscles that are most active during exercise and a respiratory crisis.

Structure of the Lungs

The lungs are located behind your rib cage on each side of your heart in your chest. They are generally conical in form, with a curved apex and a flattened foundation wherein they join the diaphragm. Your lungs, although being a pair, aren’t the same size or form. Whereas your left lung seems to have a depression designated for the cardiac notch that borders wherever the heart is located, the right lung is narrower to lend credence to the liver underneath. 

Generally, the left lung is somewhat lighter and has a lesser volume than the right. The lungs are surrounded by two membranes called pulmonary pleura. The lungs are surrounded by two membranes called pulmonary pleura. The inner layer is directly attached to the outer surface of the lungs, whereas the outer layer is attached to the inner wall of your rib cage. Pleural fluid is present in the gap between the two membranes, which keeps the pleura wet and decreases resistance between your membranes during breathing.

Alveoli

The alveoli are the final stop on the trip of oxygen from the external atmosphere to the recesses of the lungs. Alveoli are tiny sacs that are surrounded by a thin network of capillaries. The outer layer area of the membrane provided by the alveoli is around 70 metres or nearly half the length of a courtyard. Following the lungs, the body transports oxygen from the circulation to its various tissues as it circulates through the circulatory system. The blood that has exchanged oxygen for carbon dioxide from the tissues next goes via the heart and into the lungs to join the capillaries covering the alveoli.

The alveoli now hold a fresh supply of oxygen from the person’s inhalation. This oxygen enters the circulation via a membrane known as the alveolar-capillary membrane. Simultaneously, carbon dioxide that has accumulated in the circulation throughout its journey across the body reaches the alveoli. During expulsion, a person’s body breathes it directly out into the environment. Simply said, when oxygen enters, carbon dioxide exits – an instance of a gasification process.

The surfactant of the Lungs

A substance called pulmonary surfactant is produced by unique cells in your alveoli. It is made up of lipids, proteins, and carbs. Water attracts hydrophilic areas but repels hydrophobic regions in surfactants. Pulmonary surfactant serves various important tasks, including improving breathing effectiveness and keeping alveoli from crushing on themselves. 

Each alveolus resembles a damp plastic bag on the inside of the structure of the lungs. The bag would crumple in on itself in case there was no surfactant, and the inside sides would stay together. Surfactant protects the alveoli from being damaged in this way. The pulmonary surfactant performs its function by lowering surface tension. This minimises the amount of work required to expand the alveoli.

The function of the Lungs

The lungs conduct additional biological functions in addition to respiratory duties. Water, liquor, and pharmaceutical substances can be ingested and expelled through these. Just over a quart of freshwater is exhaled every day, and anaesthetic gases like ether and nitrous oxide can be ingested and eliminated by the lungs. 

The lung happens to be a real metabolic organ as well. It participates in the creation, storage, conversion, and destruction of a wide range of chemicals, including pulmonary surfactant, fibrin, and other physiologically varied compounds (i.e., histamine, prostaglandins, and angiotensin).

A person who does not participate in strenuous physical exercise and doesn’t know the structure of the lungs uses just approximately one-twentieth of the lung’s total potential gaseous-exchange surface. The pressure inside the lungs is the same as the pressure outside. Due to a partial vacuum between the membrane enclosing the lung and the membrane lining the chest, the lungs are always slightly inflated. 

Whenever the diaphragm (the muscular section between the belly and the chest) and the intercostal muscles flex, the chest cavity expands, and the pressure between your lungs and your chest wall including within the lungs decreases. This decrease in pressure within the lungs absorbs air from the surrounding environment.

Clinical Disorders

Lung disease is defined as any condition in the structure of the lungs that stops the lungs from functioning normally. Lung disease is classified into two types:

• Airway Disorders

These disorders have an impact on the tubes (airways) that transport oxygen and other gases into and out of the lungs. They often induce constriction or obstruction of the airways. Asthma, chronic obstructive pulmonary disease (COPD), and bronchiectasis are examples of airway illnesses. People with airway problems frequently describe their sensation as “trying to breathe out through a straw.”

• Lung Tissue Disorders

These disorders have an impact on the structure of lung tissue. Scarring or inflammation of the tissue prevents the lungs from properly expanding (restrictive lung disease). This makes it difficult for the lungs to absorb oxygen and expel carbon dioxide. People with this form of lung illness frequently describe themselves as “wearing a too-tight sweater or vest.” As a result, they are unable to breathe deeply. Lung tissue disease includes pulmonary fibrosis and sarcoidosis.

Conclusion

You might not even emphasise the implications of respiratory health unless you have difficulty breathing. By eliminating carbon dioxide from the body, your lungs produce oxygen and maintain every other organ in working order. Genetics, illness, as well as the surroundings, may all have an impact on the lungs’ functioning and create respiratory difficulties. Whenever your lung function is compromised, it affects your standard of living and therefore can prematurely reduce your lifetime. As a result, understanding the anatomy and structure of the lungs is critical.