.lesson-duration-container {
background-color: #f0f4f8; /* Szarawe tło dopasowane do reszty strony */
padding: 8px 15px; /* Wewnętrzny odstęp */
border-radius: 8px; /* Zaokrąglone rogi */
font-family: ‘Roboto’, Arial, sans-serif; /* Czcionka Roboto, jeśli dostępna */
font-size: 16px; /* Rozmiar tekstu */
color: #6c757d; /* Ciemny szary kolor tekstu */
display: inline-block; /* Wyświetlanie jako element blokowy */
margin-bottom: 20px; /* Odstęp na dole */
border: none; /* Bez obramowania */
}
.lesson-duration-label {
font-weight: 700; /* Pogrubienie dla etykiety */
color: #6c757d; /* Ciemny szary kolor dla etykiety */
margin-right: 5px; /* Odstęp od wartości */
}
.lesson-duration-value {
color: #6c757d; /* Ciemny szary kolor dla wartości */
font-weight: 700; /* Pogrubienie dla wartości */
}
Did You Know?
Did you know that every day, you take about 20,000 breaths without even thinking about it? The respiratory system is a remarkable network of organs and tissues that enables this essential life function. But here’s the fascinating part – the surface area of your lungs, where oxygen and carbon dioxide exchange occurs, is roughly half the size of a tennis court!
Structure of the Respiratory System
The respiratory system is divided into two main sections that work together to ensure efficient airflow and gas exchange.
Upper respiratory tract: Includes the nasal cavity, pharynx, and larynx. These structures are primarily responsible for filtering, warming, and humidifying incoming air.
Lower respiratory tract: Comprises the trachea, bronchi, lungs, and diaphragm. This section facilitates the exchange of oxygen and carbon dioxide and supports breathing mechanics.
Upper Respiratory Tract
Nasal Cavity
The nasal cavity serves as the primary entryway for air into the respiratory system. It plays an essential role in filtering, warming, and humidifying the air before it progresses into the lower respiratory tract. The nasal cavity is split into two sections by the nasal septum, which is made of bone (mainly the vomer and the perpendicular plate of the ethmoid bone) and cartilage. This septum ensures even airflow between both nasal passages.
Conchae
Within the nasal cavity, there are three bony projections on each side, known as conchae – the superior, middle, and inferior conchae. These structures increase the surface area within the nasal cavity, ensuring more effective contact between the air and the mucosal surfaces.
Superior concha: Located near the olfactory region, contributing to the sense of smell.
Middle concha: Centrally positioned, it increases the mucosal surface to trap airborne particles.
Inferior concha: The largest, responsible for humidifying and filtering inhaled air.
Mucosal Lining
The nasal cavity is lined with pseudostratified ciliated columnar epithelium, containing goblet cells that produce mucus. This mucus traps dust, pathogens, and other particles, while the cilia move the mucus toward the pharynx, where it is expelled or swallowed. This process, known as mucociliary clearance, is a vital defense against inhaled pathogens.
Olfactory Epithelium
At the upper part of the nasal cavity, the olfactory epithelium is responsible for the sense of smell. Specialized receptors in this area detect odorant molecules and send signals to the brain. Additionally, this region initiates reflexes, such as sneezing, to expel irritants.
Pharynx
The pharynx, a muscular tube roughly 12 cm in length, serves as a shared passageway for air and food. It connects the nasal cavity and mouth to the larynx and esophagus. The pharynx is divided into three regions:
Nasopharynx: Situated behind the nasal cavity, it serves solely as an air passage. It is lined with pseudostratified ciliated epithelium and contains the pharyngeal tonsils (adenoids), which aid in trapping airborne pathogens. The nasopharynx also communicates with the middle ear via the Eustachian tubes, helping to equalize ear pressure.
Oropharynx: Located behind the oral cavity, this region allows for both air and food passage. Lined with stratified squamous epithelium to resist abrasion, it houses the palatine and lingual tonsils, contributing to immune defense.
Laryngopharynx: This most inferior part of the pharynx extends from the epiglottis to the esophagus. It directs air to the larynx and food to the esophagus. The epiglottis plays a crucial role in preventing food from entering the respiratory tract by covering the laryngeal inlet during swallowing.
Larynx
The larynx, located below the pharynx, serves as both a protective gateway to the lower respiratory tract and the organ of sound production. It is composed of several cartilaginous structures:
Thyroid Cartilage: The largest cartilage, commonly known as the Adam’s apple, forms the anterior wall of the larynx.
Cricoid Cartilage: Situated below the thyroid cartilage, it forms a complete ring around the airway, providing structural support.
Arytenoid Cartilages: These paired cartilages control the tension of the vocal cords, essential for voice production.
The vocal cords, housed in the larynx, consist of two mucosal folds that vibrate as air passes through them, generating sound. Adjustments in vocal cord tension and length, made by intrinsic laryngeal muscles, allow variations in pitch and volume.
The epiglottis ensures food and liquids are directed toward the esophagus by covering the glottis during swallowing, preventing aspiration into the airway.
Lower Respiratory Tract
Trachea
The trachea, commonly known as the windpipe, is a tubular structure extending from the larynx to the primary bronchi. Measuring approximately 10 to 12 cm in length, it is supported by C-shaped rings of hyaline cartilage, which prevent the airway from collapsing.
Carina
The carina, located at the bifurcation of the trachea into the right and left main bronchi, is an important anatomical landmark. It is highly sensitive to irritation and plays a role in the cough reflex.
Tracheal Epithelium
The inner surface of the trachea is lined with pseudostratified ciliated columnar epithelium and goblet cells. This combination produces mucus that traps inhaled particles, while the cilia move the mucus upward for expulsion, a process known as mucociliary clearance.
Bronchial Tree
The bronchial tree refers to the branching system of airways extending from the trachea into the lungs.
Primary Bronchi: The trachea splits into the right and left main bronchi. The right bronchus is wider, shorter, and more vertical, making it more likely for foreign objects to enter the right lung.
Lobar Bronchi: The primary bronchi divide into lobar bronchi—three in the right lung and two in the left lung, corresponding to the lung lobes.
Segmental Bronchi: Each lobar bronchus further divides into segmental bronchi, which supply specific bronchopulmonary segments. These segments can be surgically removed without affecting other lung areas.
Bronchioles: As the airways continue to branch, they become smaller, eventually forming bronchioles. Bronchioles lack cartilage but are surrounded by smooth muscle, allowing for regulation of airflow. The smallest bronchioles, called terminal bronchioles, lead to respiratory bronchioles involved in gas exchange.
Lungs
The lungs are a pair of spongy, air-filled organs located on either side of the thoracic cavity, protected by the rib cage. The primary function of the lungs is to facilitate gas exchange between the air and blood, ensuring that oxygen enters the bloodstream while carbon dioxide is expelled. Each lung is structurally divided into lobes, segments, and smaller units, enabling efficient respiratory function.
Right Lung
The right lung is larger and broader than the left lung due to the position of the heart, which displaces the left lung. The right lung is divided into three lobes:
Superior lobe
Middle lobe
Inferior lobe
Each lobe is separated by fissures: the horizontal fissure separates the superior and middle lobes, while the oblique fissure separates the middle and inferior lobes. The right lung is shorter than the left lung because of the liver, which sits just below it, pushing the diaphragm upward on the right side.
Left Lung
The left lung is slightly smaller and has only two lobes:
Superior lobe
Inferior lobe
The left lung is divided by a single oblique fissure. The smaller size of the left lung allows room for the heart, which is accommodated by a depression on the medial surface of the lung known as the cardiac notch. Despite its smaller size, the left lung is highly efficient an
Bronchopulmonary Segments
Each lobe of the lungs is further subdivided into bronchopulmonary segments, which are independent functional units of the lung tissue. These segments are each supplied by a segmental bronchus and their own blood vessels. There are 10 bronchopulmonary segments in the right lung and 8 to 10 in the left lung. The independent nature of these segments is clinically important because they can be surgically removed (in procedures like segmentectomy) without affecting the function of the rest of the lung.
Alveoli and Gas Exchange
At the microscopic level, the lungs contain millions of alveoli, the tiny air sacs where gas exchange occurs. The structure of the alveoli maximizes surface area and minimizes the distance between the air in the alveoli and the blood in the surrounding capillaries. Oxygen from the inhaled air diffuses across the alveolar walls into the blood, while carbon dioxide from the blood diffuses into the alveoli to be exhaled.
Blood Supply
The lungs receive blood from two sources:
Pulmonary circulation: The primary route for gas exchange, where deoxygenated blood from the right side of the heart is pumped to the lungs via the pulmonary arteries. After oxygenation in the alveoli, oxygen-rich blood is returned to the left side of the heart through the pulmonary veins for systemic circulation.
Bronchial circulation: A smaller part of the circulatory system that supplies oxygenated blood to the lung tissues themselves (except the alveoli). The bronchial arteries, which originate from the thoracic aorta, deliver this blood, and the bronchial veins drain it back into the systemic venous circulation.
Lymphatic System
The lungs are equipped with an extensive lymphatic system that plays a crucial role in immune defense and fluid regulation. Lymphatic vessels in the lungs help drain excess fluid and transport immune cells, preventing the accumulation of fluids (which could cause pulmonary edema) and helping to clear any infections. The lung’s lymph nodes, including the hilar and mediastinal nodes, filter lymphatic fluid and are often evaluated in cases of lung infections, cancer, or systemic diseases.
Pleura
The lungs are encased by a double-layered serous membrane called the pleura, which consists of two layers:
Visceral pleura: The inner layer that tightly adheres to the lung surface, following its contours, including the fissures between lobes.
Parietal pleura: The outer layer that lines the inner surface of the thoracic cavity, including the rib cage and diaphragm.
Between these two layers is the pleural cavity, a thin, fluid-filled space that reduces friction during breathing. The pleural fluid in this space acts as a lubricant, allowing the lungs to expand and contract smoothly against the thoracic wall with minimal friction. This fluid also helps maintain a negative pressure within the pleural cavity, which is essential for lung expansion during inhalation. Disruption of this negative pressure, as seen in conditions like pneumothorax (collapsed lung), can severely impair breathing.
Pulmonary Innervation
The lungs receive both sympathetic and parasympathetic innervation, which regulates their function:
Sympathetic innervation (from the thoracic sympathetic chain) dilates the airways, increasing airflow, particularly during situations of stress or exercise (fight-or-flight response).
Parasympathetic innervation (via the vagus nerve) causes bronchoconstriction, reducing airflow during rest or when protecting the lungs from irritants.
Nerve endings in the lungs also play a role in reflexes such as coughing and bronchodilation in response to irritants or foreign particles.
Diaphragm
The diaphragm is a dome-shaped muscle separating the thoracic and abdominal cavities. It plays a primary role in respiration.
Inhalation: Contraction of the diaphragm increases thoracic volume, decreasing pressure and drawing air into the lungs.
Exhalation: Relaxation of the diaphragm decreases thoracic volume, expelling air from the lungs.
Inhalation: Contraction of the diaphragm increases thoracic volume, decreasing pressure and drawing air into the lungs.
Exhalation: Relaxation of the diaphragm decreases thoracic volume, expelling air from the lungs.
The diaphragm is innervated by the phrenic nerve, originating from the cervical spine (C3-C5). Damage to this nerve can lead to respiratory difficulties or failure.
Common Congenital Anomalies
Congenital anomalies of the respiratory system involve structural abnormalities in the airways, lungs, or related structures that develop during fetal life. These conditions vary widely in severity, from asymptomatic to life-threatening, and may impact breathing, lung function, and overall respiratory health. Here are some of the most frequently encountered congenital respiratory anomalies:
Congenital Respiratory Anomaly
Description
Congenital Lobar Emphysema (CLE)
CLE is characterized by hyperinflation of one or more lobes of the lung, which can compress surrounding lung tissue. It often presents in infancy with symptoms like respiratory distress or wheezing. Mild cases may be monitored, while severe cases may require surgical removal of the affected lobe to improve lung function.
Tracheoesophageal Fistula (TEF) and Esophageal Atresia (EA)
TEF and EA often occur together, where an abnormal connection exists between the trachea and esophagus, and the esophagus may be underdeveloped. These conditions typically present shortly after birth with feeding difficulties and respiratory distress. Surgical repair is required to separate the trachea and esophagus and restore normal function.
Congenital Diaphragmatic Hernia (CDH)
CDH is a defect in the diaphragm, allowing abdominal organs to move into the chest cavity and restrict lung development. It often presents in the neonatal period with severe respiratory distress. Treatment involves surgical repair of the diaphragm and may require intensive respiratory support before and after surgery.
Pulmonary Sequestration
This rare anomaly involves a non-functioning mass of lung tissue that lacks a normal connection to the airway and receives blood supply from an abnormal artery. It can cause recurrent infections and may be asymptomatic or lead to breathing difficulties. Surgical removal is often recommended to prevent complications.
Bronchogenic Cyst
Bronchogenic cysts are fluid-filled cysts in the chest, usually located near the trachea or bronchi. They may remain asymptomatic or cause respiratory symptoms like cough, wheezing, or infection if they compress airways. Surgical removal may be recommended if symptomatic or if there is a risk of infection.
Laryngeal Cleft
A laryngeal cleft is an abnormal opening between the larynx and esophagus, allowing food or liquids to enter the airway. This condition can lead to aspiration, coughing, and respiratory infections. Treatment usually involves surgical repair to close the opening and prevent aspiration.
Congenital Pulmonary Airway Malformation (CPAM)
CPAM is a cystic lesion in the lung, consisting of abnormal lung tissue that does not function properly. It may be detected prenatally or present after birth with respiratory distress or recurrent infections. Management often includes surgical resection, especially if symptomatic.
Zaloguj się
To szkolenie wymaga wykupienia dostępu. Zaloguj się.