A person breathes in and out about 24,000 times each day. Breathing is one of the most important functions of the human body. Without oxygen supply through the respiratory tract, a person dies after only a few minutes.
What are the respiratory tract?
Schematic diagram showing the anatomy of the respiratory tract in humans. Click to enlarge. The respiratory system has the task of supplying the body with vital oxygen and transporting the carbon dioxide produced to the outside. This happens completely without our intervention. The brain controls breathing automatically and ensures that breathing works even during sleep. The respiratory system is divided into two parts, internal and external respiration. The external respiration is the respiratory tract. This is the name given to those parts of the body through which air flows to the lungs and back again. They clean, humidify and warm the inhaled air. They transport the air to the lungs and the carbon dioxide produced there out of the body in the opposite way. Internal respiration begins in the lungs. From here, oxygen is distributed throughout the body by the blood.
Anatomy and structure
The nose, sinuses, mouth and pharynx form the upper respiratory tract, and the larynx, trachea, bronchi and alveoli form the lower respiratory tract. Inhaled air passes through the nose into the pharynx, the back of the oral cavity. The air and food passages meet in the pharynx. Only at its lower end, the larynx, do they separate into airways with larynx and trachea and the esophagus behind them. The larynx forms the transition from the upper to the lower respiratory tract. The trachea is a soft, expandable tube. The walls are reinforced by cartilaginous rods, which are internally covered with mucosa and cilia. It is about 10 to 12 cm long and merges at the lower end into the two main bronchi. These fork into smaller and smaller branches until they become bronchioles. Through these, the air finally reaches the alveoli, through whose walls the actual exchange of gases with the lungs takes place.
Function and tasks
Schematic diagram showing the anatomy and structure of the lungs and bronchi. Click to enlarge. The nose filters up to 12,000 liters of inhaled air daily. It is completely covered with mucous membrane on the inside. It humidifies the air and its blood vessels warm it. Fine cilia transport dirt particles, viruses and bacteria in the air we breathe back to the outside. Processed to fit the body, the air continues to flow through the pharynx to the larynx. The laryngeal cap acts as a pilot between the trachea and the esophagus. When swallowing, it closes, allowing food to drain into the esophagus. When breathing, it opens, and air flows through the larynx into the trachea. This carries the air from the throat down into the bronchi. Mucus and ciliated hairs on their inner wall bind ingested dust and foreign bodies and push them back to the throat. The bronchi distribute air evenly to the lobes of the lungs and pass it on to the alveoli. The bronchi are packed with mucus and ciliated hairs that bind residual particles from the air and carry them upward toward the throat by coughing them up. This prevents the alveoli from becoming clogged with invading pathogens and pollutants. The alveoli are responsible for the exchange of oxygen and carbon dioxide between the blood and the air we breathe. The two are separated by an extremely thin membrane, through which they pass unimpeded. The oxygen from the breathing air flows into the blood. At the same time, carbon dioxide from the blood flows into the alveoli.
Diseases and ailments
The human respiratory system is extremely sensitive and susceptible to various diseases that can affect it. Often it is viruses that cause a cold with typical symptoms such as cold, cough and sore throat. Not infrequently, bronchitis is added to the mix. It manifests itself with a violent cough, mucous sputum and a slight fever. Bronchitis usually subsides after a week. Bronchitis is considered chronic if the cough and sputum occur for at least three months each in two consecutive years. True flu (influenza) is a viral infection that usually occurs suddenly. It is accompanied by a high fever of up to 39/40° Celsius, severe headache and pain in the limbs, and a pronounced feeling of weakness. Influenza should always be treated by a doctor.Asthma is an inflammatory hypersensitivity reaction of the bronchi to certain substances such as dust, animal hair or cold air. Stress or excitement can also be the trigger. Frequent coughing fits, shortness of breath and whistling breathing noises are the result. Sometimes allergens affect the airways. The best known is hay fever, which is triggered by pollen. Every year in spring, sufferers are plagued by violent sneezing attacks, nasal congestion and runny nose. These are still the most harmless complaints. In some patients, shortness of breath and severe coughing attacks, even asthma, are added.
