Lung Anatomy, Function and Diseases

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The knowledge of human body is what differentiates Biomedical Engineering from other groups of Engineering, with that in mind we have started a new segment in Biomedical Views to discuss about Anatomy and physiology of various human organs.

From now viewers can expect mixed variety of topics in our blog like Medical devices, Anatomy and Physiology, Medical Device regulatory, Recent trends in Biomedical Engineering and Healthcare.

Today we are going to discuss about Lung Anatomy, Function and Diseases.

The lungs are one of the important organs in human body which facilitates the breathing process. Therefore it is important for every healthcare professional to know in detail about Lungs.

Let's get into the topic.

WHAT IS LUNG?

The lungs are the main organ of respiratory systems. The respiratory system is responsible for inhaling oxygen (inspiration) and exhaling carbon dioxide (expiration). As we breathe, air from the atmosphere enters lungs and lungs are responsible for transporting oxygenated air to the red blood cells. And the oxygen in the red cells are utilized by all the cells of our body. The lungs are also responsible for getting rid of carbon dioxide from deoxygenated blood as we breathe out.

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WHAT IS THE PATHWAY OF BREATHING?

When we breathe, air from the atmosphere enters into the mouth and nose. Then the air reaches the trachea through throat and larynx. Here the trachea divides into two hollow tubes called bronchus. The right bronchus connects to the right lung and left bronchus connects to the left lung. The bronchus are further divided into smaller air tubes called bronchioles. At the end of bronchioles, there is a small tiny air sac called as alveoli is present. The air travels in this structure and reaches the alveoli.

HOW GAS EXCHANGE TAKES PLACE?

The air entering the lungs reaches alveoli through bronchioles. The alveoli are tiny air sacs in the lung where the exchange of oxygen and carbon dioxide takes place. There are about 600 millions of alveoli in our human body.

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HOW IS THE ANATOMY OF LUNGS?

Lungs are a pair of spongy air filled organs located on either side of the chest wall ( thorax). Lungs are conical in shape with rounded point at their apex and flatter base where they meet the diaphragm. The right lung is shorter to accommodate the liver below. And left lung has an indentation bordering where the heart accommodates. It is called as cardiac notch. Left lung is smaller and lesser in capacity compared to right lung.

WHAT IS DIAPHRAGM?

Diaphragm is a dome shaped muscle sheet which separates chest from the abdomen. During inhalation diaphragm flattens and contracts which enlarges the chest cavity, and air enters into the lungs. During exhalation diaphragm relaxes and retains it's dome shape and air is forced out of lungs.

WHAT ARE THE LAYERS OF LUNGS?

Lungs are covered by two protective layers as following

Visceral Layer (Inner Layer) which covers the lung.

Parietal Layer( Outer Layer) which covers the chest cavity.

WHAT ARE THE PARTS OF LUNGS?

The lungs are divided into right lung and left lung. Each lung can be divided into following lobes.

The right lung can be divided into Upper Lobe, Middle Lobe, Lower lobe. The left lung is divided into Upper lobe, Lower lobe

WHAT ARE THE FUNCTIONS OF LUNGS?

One of the important function of lungs is that it is responsible for the change pH of blood in human body ( whether the blood is more acidic or more alkali). Lungs maintains the pH of blood by increasing or decreasing the amount of carbon dioxide in the body.

Lungs also plays an important role in conversion of Angiotensin 1 to Angiotensin 2. These chemicals are responsible for the maintenance of normal blood pressure in human body.

Lungs acts as a blood reservoir which is considered as a crucial function of lungs. The lungs contains about 500 to 1000 ml of blood which is useful during exercise. Lungs interact with heart and help them work more efficiently at the time of exercise.

The mucus that lines the respiratory passages traps dust particles and bacteria. Cilia (tiny hair like projections) , move the dust particles and bacteria towards upward position where they will be coughed out or swallowed and destroyed by digestive system.

Certain membranes of Lungs secretes Immunoglobulin -A which protects the lungs from some infections. Another important function of lungs is that in certain types of collision lungs acts as a shock absorber for the heart. Lungs filter small blood clots and remove small air bubbles ( known as embolism) ,if they occur.

RESPIRATORY SYSTEM DISEASES

Respiratory system diseases are categorized into two main categories, Infections and chronic diseases

Some of the common disease in lungs are:

ASTHMA

Asthma is a respiratory condition in which patients air is narrow ,inflamed, swell and produce extra mucus and makes it difficult to breathe.

BRONCHIECTASIS

Bronchiectasis is a condition where mucus collects in the lungs and there is a risk of infection. It results in irreversible dilation of bronchi.

PNEUMONIA

Pneumonia is a infection of lung in which air sacs are filled with pus or fluid and makes it difficult to breathe.

TUBERCULOSIS

Tuberculosis is a contagious infectious disease ,which spreads to other parts of the body.

CHRONIC OBSTRUCTIVE PULMONARY DISEASE

COPD is a group of lung diseases which leads to obstruction of air flow to the lungs which interferes the normal breathing.

LUNG CANCER

Is an uncontrolled growth of abnormal cells in the lung.

CYSTIC FIBROSIS

Cystic Fibrosis is a hereditary disorder which affects the cells that produce mucus, sweat and digestive juices. It leads to infection by causing sticky mucus to build up in the lungs and digestive system

PLEURAL EFFUSION

Also commonly referred as " water on the lungs". The Pleural Effusion is build up of excess of fluids between the layers of pleura outside the lungs.

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IDIOPATHIC PULMONARY FIBROSIS

Is a chronic progressive disease which results in the scarring (fibrosis) of lung tissues.

SARCOIDOSIS

Sarcoidosis is an inflammatory condition in any part of our body , which most commonly affects lungs and lymph nodes.

Now I hope you have acquired some knowledge about Lungs Anatomy, Function and Diseases. We will discuss in detail about a topic related to Biomedical Engineering in our future blogs.

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Content contributed by

Varshini, MBBS, Final Year

Let’s here from our Team mate,

Hello all !!!

I’m very happy and excited to be associated with Biomedical Views. Being a Medical student it’s always a dream to share my thoughts and knowledge to the healthcare professionals. Hope this journey helps others and myself to gain knowledge in the field of healthcare.

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