Lesson 2 THE RESPIRATORY SYSTEM
THE RESPIRATORY SYSTEM
The human respiratory system is a series of organs responsible for taking in oxygen and expelling carbon dioxide. The primary organs of the respiratory system are lungs, which carry out this exchange of gases as we breathe.
Red blood cells collect the oxygen from the lungs and carry it to the parts of the body where it is needed, according to the American Lung Association. During the process, the red blood cells collect the carbon dioxide and transport it back to the lungs, where it leaves the body when we exhale.
The human body needs oxygen to sustain itself. A decrease in oxygen is known as hypoxia and a complete lack of oxygen is known as anoxia, according to the National Institutes of Health. These conditions can be fatal; after about four minutes without oxygen, brain cells begin dying, according to NYU Langone Medical Center, which can lead to brain damage and ultimately death.
In humans, the average rate of breathing depends on age. A newborn's normal breathing rate is about 40 times each minute and may slow to 20 to 40 times per minute when the baby is sleeping, according to the Children's Hospital of Philadelphia.
For adults, the average resting respiratory rate for adults is 12 to 16 breaths per minute, according to Johns Hopkins Medicine. Physical exertion also has an effect on respiratory rate, and healthy adults can average 45 breaths per minute during strenuous exercise.
Parts of the respiratory system
As we breathe, oxygen enters the nose or mouth and passes the sinuses, which are hollow spaces in the skull. Sinuses help regulate the temperature and humidity of the air we breathe.
The trachea, also called the windpipe, filters the air that is inhaled, according to the American Lung Association. It branches into the bronchi, which are two tubes that carry air into each lung. (Each one is called a bronchus.) The bronchial tubes are lined with tiny hairs called cilia. Cilia move back and forth, carrying mucus up and out. Mucus, a sticky fluid, collects dust, germs and other matter that has invaded the lungs. We expel mucus when we sneeze, cough, spit or swallow.
The bronchial tubes lead to the lobes of the lungs. The right lung has three lobes; the left lung has two, according to the American Lung Association. The left lung is smaller to allow room for the heart, according to York University. Lobes are filled with small, spongy sacs called alveoli, and this is where the exchange of oxygen and carbon dioxide occurs.
The alveolar walls are extremely thin (about 0.2 micrometers). These walls are composed of a single layer of tissues called epithelial cells and tiny blood vessels called pulmonary capillaries.
Blood passes through the capillaries. The pulmonary artery carries blood containing carbon dioxide to the air sacs, where the gas moves from the blood to the air. Oxygenated blood goes to the heart through the pulmonary vein, and the heart pumps it throughout the body.
The diaphragm, a dome-shaped muscle at the bottom of the lungs, controls breathing and separates the chest cavity from the abdominal cavity, the American Lung Association noted. When a breath it taken, it flattens out and pulls forward, making more space for the lungs. During exhalation, the diaphragm expands and forces air out.
Diseases of the respiratory system
Diseases and conditions of the respiratory system fall into two categories: viruses, such as influenza, bacterial pneumonia, enterovirus respiratory virus; and chronic diseases, such as asthma and chronic obstructive pulmonary disease (COPD). According to Dr. Neal Chaisson, who practices pulmonary medicine at the Cleveland Clinic, there is not much that can be done for viral infections but to let them run their course. "Antibiotics are not effective in treating viruses and the best thing to do is just rest," he said.
COPD
COPD is the intersection of three related conditions — chronic bronchitis, chronic asthma and emphysema, Chaisson told Live Science. It is a progressive disease that makes it increasingly difficult for sufferers to breath.
Asthma
Asthma is a chronic inflammation of the lung airways that causes coughing, wheezing, chest tightness or shortness of breath, according to Tonya Winders, president of the Allergy & Asthma Network. These signs and symptoms may be worse when a person is exposed to their triggers, which can include air pollution, tobacco smoke, factory fumes, cleaning solvents, infections, pollens, foods, cold air, exercise, chemicals and medications.
Lung cancer
Lung cancer is often associated with smoking, but the disease can affect non-smokers as well. Every year, about 16,000 to 24,000 Americans die of lung cancer, even though they have never smoked. In 2018, the American Cancer Society estimates there will be about 234,030 new cases of lung cancer (121,680 in men and 112,350 in women) and around 154,050 deaths from lung cancer (83,550 in men and 70,500 in women).
Types of Lung & Respiratory
AllergiesAllergies are caused by hypersensitivity of our immune system. People with allergies are often sensitive to substances like pollen, dust mites, mold spores, pet dander, food, insect stings, medicines etc. Learn more about the various types of allergies, some common symptoms and various treatment options.
Aspiration PneumoniaAspiration pneumonia is a type of lung infection that occurs when you inhale food, stomach acid, or saliva into your lungs. Infection can be caused by a variety of bacteria. Symptoms of aspiration pneumonia may include fever, cough, and lung abscess. Antibiotics are the first choice to treat aspiration pneumonia.
AsthmaAsthma is a chronic inflammatory disease that inflames the airways of bronchi in the lungs. Asthma causes shortness of breath, coughing, chest tightness, and episodes of wheezing (whistle like sound while breathing). Read more to know about the causes, symptoms and what you can do for treating asthma.
Breathing DifficultyShortness of breath is the distressing sensation that breathing requires more effort than usual. People who experience shortness of breath — also known as dyspnea — describe the sensation as an intense tightening in the chest, so-called “air hunger,”
More in Breathing Difficulty
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