Introduction to Lungs
Lungs are one of the most vital organs, not only in the human body but in every mammal. A crucial part of your Biology curriculum, read this article to learn about the important facts of lungs and related ailments.
Lungs are of central importance in the human respiratory system. It enables gaseous exchange between both inhaled and exhaled air with that of blood.
Respiratory system facts indicate that the system as a whole and the lungs in particular
help to allow the oxygen present in the air to be taken within the body. It also releases waste of carbon dioxide into the air.
Parts of Lungs
Let us take a look at the structure of this organ before we move on to know more about
lungs.
Lungs are a pair of air-filled spongy organs that are located on both sides of the chest. The windpipe or trachea passes inhaled oxygen to lungs through fine tubular branches which are called bronchi.
The bronchioles end in minuscule air sacs known as alveoli. Inhaled oxygen undergoes absorption into the blood within the alveoli.
Lungs are also covered by a fine layer of tissue called pleura. It primarily acts as a
lubricant for the extraction and contraction of lungs with every single breath.
Functions of Lungs
Apart from enabling breathing, lungs perform other functions such as -
1. Lungs engage in filtering small blood clots and air bubbles.
2. It can act as a shock absorber for a heart in instances of mild collision.
3. The mucus that covers respiratory passages helps in trapping bacteria and dust particles.
4. Lungs also act as blood reservoirs which may vary from 500 ml to 1000 ml.
5. Airflow through the lungs enables speech.
Diseases of Lungs
1. Chronic Obstructive Pulmonary Disease (COPD): A patient suffering from COPD experiences difficulty in exhaling, leading to shortness of
breath. The major cause of COPD has been found to be smoking.
2. Chronic Bronchitis: It involves frequent coughing with difficulty in breathing. Chronic Bronchitis is
a variant of COPD.
3. Asthma : Asthma may be triggered by air pollution, viral infections and allergies. It causes wheezing, shortness of breath, spasm and inflammation of the bronchi.
4. Pneumonia : Streptococcus pneumoniae bacteria cause infection in the lungs.
5. Pleurisy : Pleurisy causes inflammation of the pleura, causing difficulty in inhalation.
6. Tuberculosis : Mycobacterium tuberculosis causes pneumonia to progress. Symptoms of tuberculosis include weight loss, fever, cough and night sweats, among others.
Importance of Lungs
Lungs are an important organ in our bodies that help us breathe
The air that we breathe in contains oxygen and we need it to survive
Lungs help in filtering out carbon dioxide from the body
Lungs also filter small blood clots
They can act as a shock absorber for the heart when it comes to collisions
They help in clearing mucus
They help humans speak
How to Prepare Notes on Lungs in Biology?
Students of Biology can read and prepare for Biology from Vedantu’s online tutoring platform. They can scan this note and then write down all the concepts in a sequential manner. They can take brief notes of what’s on the page and then write them as per their own understanding of the topics.
They can use bullet points, illustrations and coloured pens to mark key portions as highlighting the important parts makes it easier to go through them at the time of revision. They can then compare whatever they have jotted with what’s actually on the page for an overall analysis.
Did You Know?
One of the amazing fact about the respiratory system is that human lungs are not of
the same size. The right lung is larger than their left lung as this latter has to accommodate the heart.
Test Your Knowledge
I. Gaseous exchange between blood and inhaled air is known as -
(a) Circulatory respiration
(b) Internal respiration
(c) External respiration
(d) Cellular respiration
ii. Which of the following relates to a maximum volume of air that may be inhaled into the lungs with full force intake?
(a) Inspiratory capacity
(b) Total lung capacity
(c) Tidal volume
(d) Vital capacity
Solutions: i. (c) External respiration, ii. (d) Vital capacity
Learn more about lungs and other related topics through our online classes. You can also download a free pdf solution that will enhance your knowledge. You can now even download our Vedantu app for easier access to these notes and online interactive sessions.
FAQs on Facts About Lungs
1. What is the primary function of the lungs in the human body?
The primary function of the lungs is gaseous exchange, a vital part of the respiratory process. They take in oxygen from the air we inhale and transfer it into the bloodstream. Simultaneously, they collect carbon dioxide, a waste product, from the blood and expel it from the body when we exhale.
2. What are the main parts of the human respiratory system that lead to the lungs?
Air travels through a specific pathway to reach the lungs for gas exchange. The main parts involved are:
- Trachea (Windpipe): The main tube that carries air from the throat towards the chest.
- Bronchi: The trachea divides into two main bronchi, one for each lung.
- Bronchioles: Inside the lungs, the bronchi branch into smaller and smaller tubes called bronchioles.
- Alveoli: The bronchioles end in tiny, clustered air sacs called alveoli, which is where the actual gas exchange with the blood occurs.
3. Why is the right lung typically larger and heavier than the left lung?
The size difference between the lungs is a fascinating example of anatomical design. The left lung is smaller because it needs to share space in the chest cavity with the heart, which is tilted towards the left. The indentation in the left lung to accommodate the heart is known as the cardiac notch. The right lung, having more space, is consequently larger and consists of three lobes, whereas the left lung has only two.
4. How does the process of gaseous exchange actually happen in the alveoli?
Gaseous exchange in the alveoli occurs through a process called diffusion. Each alveolus is wrapped in a dense network of tiny blood vessels called capillaries. The walls of both the alveoli and the capillaries are extremely thin (one cell thick). Because the inhaled air has a high concentration of oxygen and the blood has a high concentration of carbon dioxide, oxygen diffuses from the alveoli into the blood, while carbon dioxide diffuses from the blood into the alveoli to be exhaled.
5. Besides breathing, what are some other important functions of the lungs?
While respiration is their main role, lungs perform several other vital functions. Some important examples include:
- Filtering Blood: They can filter out small blood clots that may have formed in the veins.
- Protection: The lungs act as a soft cushion, providing some shock absorption for the heart during minor impacts.
- Immune Defence: The mucus lining the airways, known as the mucous escalator, traps dust, bacteria, and other particles, which are then removed to prevent infections.
- Speech: The flow of air from the lungs across the vocal cords is essential for producing sound and enabling speech.
6. What are some common diseases that affect the lungs?
Several diseases can impair lung function. Some of the most common ones explained in the NCERT syllabus are:
- Asthma: A chronic condition causing inflammation and narrowing of the airways, leading to wheezing and shortness of breath.
- Pneumonia: An infection that inflames the alveoli in one or both lungs, which may fill with fluid or pus.
- Chronic Bronchitis: Persistent inflammation of the bronchial tubes, which leads to a nagging cough and mucus production.
- Tuberculosis (TB): A serious infectious disease caused by bacteria that mainly attacks the lungs.
7. How does the structure of the alveoli make them perfectly suited for gas exchange?
The alveoli are masterpieces of biological engineering, and their structure is optimised for efficient gas exchange in several ways. Firstly, their vast surface area (about 70 square metres in an adult) allows a large amount of gas to be exchanged at once. Secondly, their walls are extremely thin, which shortens the diffusion distance for gases. Finally, they are covered in a dense network of capillaries, ensuring a rich blood supply is always close to the air, maintaining a steep concentration gradient for rapid diffusion.
8. Where are the lungs located in the body and how are they protected?
The lungs are located in the thoracic cavity (the chest), on either side of the heart. They are well-protected by the rib cage, which forms a bony shield against physical injury. Additionally, each lung is encased in a two-layered membrane called the pleura. The fluid between these layers acts as a lubricant, allowing the lungs to expand and contract smoothly during breathing.
9. How does smoking cause damage to the lungs?
Smoking severely damages the lungs in multiple ways. The tar in cigarette smoke coats the delicate alveoli, reducing the surface area available for gas exchange and making breathing less efficient. It also paralyses and destroys the cilia, the tiny hair-like structures that clear mucus and debris from the airways. This leads to mucus buildup (smoker's cough) and increases the risk of infections like bronchitis. Over time, it can lead to permanent damage and diseases like emphysema and lung cancer.
10. Can a person survive with only one lung, and how does the body adapt?
Yes, a person can live a relatively normal life with only one lung. When one lung is removed (a procedure called a pneumonectomy), the body adapts remarkably. The remaining lung, along with the diaphragm muscle on that side, gradually shifts and expands to occupy more space in the chest cavity. This process, known as compensatory hyperinflation, increases the volume and capacity of the single lung, allowing it to perform the work of two, although peak aerobic capacity might be reduced.
