The lungs are located in the chest and are part of the respiratory system. Their most important task is to carry oxygen from the air to the blood and to remove carbon dioxide from the blood to the outside. The lungs also play a different role - they defend the body against harmful substances in the air, such as pollution, tobacco smoke, bacteria and viruses. Find out how the lungs are built, what their work is and what diseases this organ is related to.
Contents:
- Lung structure
- Lung functions
- Lung capacity
- Lung diseases
The lungsis the main part of the respiratory system. They are shaped like cones with a vesicular (spongy) structure and occupy most of the chest.
They are surrounded by ribs and intercostal muscles and are limited from below by the diaphragm. The two lungs are separated from each other by the mediastinum, in which lies, among others, heart.
This paired organ plays an important role in the body. It is thanks to the lungs that we breathe, but not only.
The lungs are a kind of filter that prevents any impurities and other undesirable substances from entering our body.
Lung structure
The two lungs are slightly different from each other.
The right lungconsists of three lobes: upper, middle and lower, separated by horizontal and oblique slits.
Left lung- from two lobes: upper and lower, separated by an oblique fissure - and it is smaller than the right one. It even has a special heart recess (cardiac notch, cardiac impression) surrounded by a pericardium.
The outer wall of the lungs is called the pleura. It is made of connective tissue and not only covers the lungs, but also lines the inside of the chest. It produces a special fluid that allows the lungs to move freely during the breathing movements in the chest.
- parietal pleura- outer pleura covering the chest walls
- pulmonary pleura- inner pleural layer covering the lung
The space between them is the pleural cavity. The lungs are reached by the trachea, i.e. the respiratory tract that runs through the neck. Between the lungs, it splits into two parts, i.e. the main bronchus.
Like the trachea, the main bronchi are surrounded by a layer of smooth muscles,Reisessen's membrane (under the influence of certain factors, e.g. irritants, these muscles may contract, which is one of the factors leading to bronchial asthma).
Each bronchus extends to one lung, along with the pulmonary artery and pulmonary vein in a place called the cavity.
In the lungs, the main bronchi branch into the lobar bronchi.
Right main bronchusis divided into three lobe bronchi entering the right lung, andleft main bronchusinto two lobe bronchi entering the right lung to the left lung.
Each lobe bronchus is then divided intosegmental bronchus(containing small glands and cartilage in the wall), and these are further divided into even smaller onesinterlobular bronchifollowed bybronchioles(which no longer contain cartilage or glands). These are narrow tubes, approx. 1 mm in diameter.
At the end of each bronchiolus ispulmonary cluster , which is about 300 million tiny alveoli (the diameter of the alveolar is 150-250 µm) surrounded by tiny capillaries ( capillaries).
Alveoliare lined with epithelial cells (type I, II, and III pneumocytes) that have thin projections called cilia. Thanks to the alveoli, the area of the lungs is approx. 90-100 m22 .
The lungs make a substance composed of fats and proteins called a surfactant. It is a surface agent that reduces the tension in the alveoli.
Covers their surface, making it easier for them to fill and deflate with each breath. It consists of lipoprotein molecules secreted by pneumocytes.
Surfactantprevents bubbles from stretching too much when inhaling, and their walls do not stick together when exhaling.
Surfactant deficiency is the cause of, among others, neonatal respiratory distress syndrome. It is associated with lung immaturity and is common in premature babies.
Lack of this fluid causes easy collapse of alveoli and the formation of atelectasis. Therefore, the gas exchange is hindered and hypoxia occurs.
Lung functions
- Breathing- The primary function of the lungs is breathing. The gas exchange process is based on the fact that the air that we breathe in with the help of suction and pressure movements of the chest through the nose or mouth passes successively through the trachea, bronchi and bronchioles to the alveoli. It is there that the absorption of oxygen that enters the blood and is distributed with hemoglobin to all cells of the body. WhereasAs you exhale, carbon dioxide is removed through the alveoli.
- Filtering- along with the air, various undesirable substances such as viruses, bacteria, pollutants (e.g. exhaust fumes), tobacco smoke, allergens also get into the lungs. However, the lungs produce a thick mucus that can completely or partially trap the cilia of the bronchioles and render these substances harmless. We get rid of most of them by grunting and swallowing or coughing.
Lung capacity
During a test called spirometry, you can test your lung capacity (TLC - total lungs capacity). The device for this is the spirometer and the spirometry record is the spirogram.
The spirometer is equipped with a gas analyzer, filled with a 10% helium mixture. Human (adult) TLC is approximately 5 liters of air. During one minute, an adult makes from 16 to 20 inhalations and exhalations, and e.g. a newborn around 40.
Even with the deepest exhalation, about 1.2 liters of air remain in the lungs. Otherwise, the lungs would collapse. This is called residual volume of the lungs.
During an average inhalation, about 500 ml of air reach the lungs, which is called the tidal volume. However, if we take a maximum, deep breath, even about 4 liters of air (the so-called vital capacity) can reach them.
Lung diseases
The following symptoms may be evidence of a lung disease:
- shortness of breath
- cough
- wheezing
- shortness of breath
- rapid breathing (gasp)
- accelerated heartbeat
- chest pain
- pulling in intercostal space
- increased body temperature
The lungs suffer from viral, bacterial or fungal infections, but also due to genetic conditions - e.g. cystic fibrosis - or cancer. The most common diseases are inflammations of various etiologies, i.e. pneumonia.
We distinguish, among others :
- environmentally acquired pneumonia (caused e.g. by pneumococci or H.Influenzae )
- environmentally acquired atypical pneumonia (caused by mycoplasmas, chlamydia, viruses)
- nosocomial pneumonia
- aspiration pneumonia (as a result of swallowing disorders, vomiting or esophagus pathology)
- chronic pneumonia
- pneumonia in immunocompromised people (e.g. in the course of AIDS or advanced cancer)
Other lung diseases include :
- chronic obstructive pulmonary disease (COPD)
- pneumoconiosis
- lung cancer
- emphysema
- asthma
- tuberculosis
- Newborn Respiratory Disorder Syndrome
Marta Uler A journalist specializing in he alth, beauty and psychology. She is also a diet therapist by education. Her interests are medicine, herbal medicine, yoga, vegetarian cuisine and cats. I am a mother of two boys - a 10-year-old and a 6-month-old.
Read more articles by this author