How Do Human Lungs Work? Exploring Functions and Vital Roles
Respiration is carried out by different muscular systems in different species. Mammals, reptiles, and birds use their muscles to support breathing. In humans, the main muscle of respiration that supports breathing is the diaphragm. The lungs provide airflow that makes the vocal sounds including human speech possible.
In the respiratory system of humans, the lungs are considered the primary organs. In mammals and most other vertebrates, the lungs are located near the backbone on either side of the heart. The function of the lungs in the respiratory system is to carry oxygen from the atmosphere to the blood vessels and to release the carbon dioxide from the blood vessels into the atmosphere, in a process of gas exchange.
Let us learn more about lungs, their features, anatomy, functions, and location. We will also discuss the disorders that can be caused.
Information about Lungs - Anatomy
The lungs meaning is as follows are located on either side of the heart in the rib cage. The lungs are conical in shape, where the top of the lungs consists of a narrow round apex, and the base is broad concave-shaped. This base is situated on the surface of the diaphragm which is found to be convex-shaped.
The lungs can stretch from the backbone in the rib cage to the front of the chest and downwards from the lower part of the trachea to the diaphragm.
Some of the space that is dedicated to the left lung is shared with the heart and has an indentation in its border that is called the cardiac notch of the left lung.
The lungs are surrounded by the pulmonary pleura. The pleurae are two serous membranes; the inner wall of the rib cage is lined by outer parietal pleura lines and the surface of the lungs is lined by inner visceral pleura. The pleural cavity is present in between the potential space that is found in the structure called pleurae. This pleural cavity contains a thin layer of lubricating fluid called pleural fluid.
Right Lung
The right lung has different lobes and segments. The lobes are divided into three parts, an upper, middle, and lower lobe by two fissures that are oblique and horizontal. The upper horizontal fissure separates the upper lobe from the middle lobe. The lower oblique fissure separates the lower lobe from the middle and upper lobes and is closely aligned with the oblique fissure in the left lung.
The cardiac impression is the impression where the heart sits. The weight of the right lung varies between individuals in men and women, in men it varies from 155–720 g, and in the case of women, the weight of the right lung is about 100–590 g.
Left Lung
The left lung is divided into two lobes by an oblique fissure; they are an upper and a lower lobe. The left lung does not contain a middle lobe. There is a projection of the upper lobe that is termed as lingula means the "little tongue", this projection is a homologous structure. The lingula on the left lung acts as the middle lobe, with both areas being predisposed to similar infections and anatomic complications. The lingula has two bronchopulmonary segments: superior and inferior.
The weight of the left lung in men is 110–675 g in women 105–515 g.
Features of Lungs
Lungs definition provides the major features of it, and the remaining ones are as follows:
Humans have two lungs; they are right lung, and left lung, which is situated within the thoracic cavity of the chest. As the left lung shares some space with the heart, the right lung is said to be bigger than the left lung.
The lungs together weigh approximately 1.3 kilograms. The lungs receive air breathed in via the conducting zone and are considered as the part of the lower respiratory tract that starts at the trachea and branches into the bronchi and bronchioles.
The conducting zone ends at the terminal bronchioles. These bronchioles divide into the respiratory bronchioles of the respiratory zone which divide into alveolar ducts that give rise to the alveolar sacs that include the alveoli that help in the exchange of gases.
Alveoli are present on the walls of the respiratory bronchioles and alveolar ducts. The lungs contain 300 to 500 million alveoli and approximately 2,400 kilometers of airways.
Lung lobes definition is as follows, lungs are enclosed within a pleural sac that contains pleural fluid, which allows the inner and outer walls to slide over each other while the process of breathing, without much friction. This pleural sac helps to divide each lung into several sections called lobes.
The lobes are further divided into pulmonary lobules and bronchopulmonary segments. The lungs have a unique blood supply; they receive deoxygenated blood from the heart and release the carbon dioxide in the pulmonary circulation, and supply of oxygenated blood to the tissues of the lungs, in the bronchial circulation.
Conclusion
According to lungs meaning, it is understood that lungs are the most important organs that are required to survive. As every cell that is present in the body requires oxygen, and to gather oxygen that is present in the atmosphere is done by a process called breathing. This process of breathing is possible only in the presence of lungs in the body.
FAQs on Human Lung: Structure, Functions, and Key Facts
1. What are the human lungs and where are they located in the body?
The human lungs are a pair of primary, spongy, air-filled organs responsible for respiration. They are located within the thoracic cavity (the chest), on either side of the heart. The entire structure is protected by the rib cage.
2. What is the main function of the human lungs?
The primary function of the lungs is gaseous exchange. This involves taking in oxygen from the atmosphere when we inhale and transferring it to the bloodstream. Simultaneously, they collect waste carbon dioxide from the blood and expel it from the body when we exhale. This process is essential for cellular respiration, which provides energy to the body's cells.
3. What is the difference in size and structure between the right and left lung?
The two lungs are not identical. The right lung is shorter and wider than the left and is divided into three sections, known as lobes. The left lung is narrower and longer, containing only two lobes. This anatomical difference exists to accommodate other organs; the right lung is shorter to make space for the liver situated below it, while the left lung has a depression called the cardiac notch to house the heart.
4. How does the unique structure of alveoli enable efficient gas exchange?
The alveoli are the functional units of the lungs where gas exchange occurs. Their structure is perfectly adapted for this role in several ways:
- Extremely Thin Walls: Each alveolus has a wall that is only one cell thick, which minimises the distance gases need to travel to enter or exit the bloodstream.
- Massive Surface Area: The millions of tiny alveoli in the lungs collectively create a vast surface area (roughly the size of a tennis court), maximising the space available for diffusion.
- Rich Capillary Network: They are enveloped by a dense web of blood capillaries, ensuring that a large volume of blood is always in close contact for rapid exchange of oxygen and carbon dioxide.
- Moist Lining: The inner surface is coated with a thin layer of fluid, which allows oxygen to dissolve before it passes through the membrane.
5. What is the purpose of the pleural membrane that surrounds the lungs?
The lungs are enclosed by a two-layered protective membrane called the pleura. The inner layer (visceral pleura) covers the lungs, and the outer layer (parietal pleura) lines the chest cavity. The space between these layers, the pleural cavity, contains a thin film of pleural fluid. This fluid serves two key purposes: it acts as a lubricant to allow the lungs to expand and contract smoothly without friction, and it creates surface tension that helps keep the lungs adhered to the chest wall, preventing them from collapsing.
6. Besides breathing, what are some other important functions of the lungs?
While gaseous exchange is their primary role, the lungs perform several other vital secondary functions:
- Blood pH Regulation: They help maintain a stable pH in the blood by controlling the level of carbon dioxide.
- Filtration: They can filter out small blood clots that may have formed in the veins.
- Vocalisation: The passage of air from the lungs across the vocal cords is necessary to produce sound for speech.
- Protection: They act as a soft cushion, providing some protection for the heart.
7. How do the lungs protect themselves from inhaled dust and germs?
The respiratory system has an effective, multi-layered defence system. The airways are lined with a sticky substance called mucus, which traps inhaled particles like dust, pollen, and bacteria. This mucus is constantly moved upwards by tiny, hair-like structures called cilia, in a mechanism known as the mucociliary escalator. This allows the trapped particles to be coughed out or swallowed. For any particles that manage to reach the deep lung tissue, specialised immune cells called alveolar macrophages are present to engulf and destroy them.
8. Why are human lungs unable to breathe in water?
Human lungs are specifically adapted to extract oxygen from the air, a gas mixture containing approximately 21% oxygen. In contrast, fish gills are designed to extract the much lower concentration of dissolved oxygen from water. Lungs lack the specialised structure of gills (like filaments and lamellae) required for this process. If a human were to inhale water, the lungs would fill with fluid, making it impossible for the alveoli to perform gas exchange, leading to a fatal lack of oxygen, a condition known as drowning.
