Review Guide Respiratory System
- Respiratory System Diseases
- Review Guide Respiratory System Biology Corner Answer Key
- Review Guide Respiratory System
Nose The respiratory system of humans begins with the nose, where air is conditioned by warming and moistening. Bone partitions separate the nasal cavity into chambers, where air swirls about in currents. Hairs and hairlike cilia trap dust particles and purify the air. Pharynx The nasal chambers open into a cavity at the rear of the mouth called the pharynx (throat). From the pharynx, two tubes called Eustachian tubes open to the middle ear to equalize air pressure there. The pharynx also contains tonsils and adenoids, which are pockets of lymphatic tissue used to trap and filter microorganisms. Trachea After passing through the pharynx, air passes into the windpipe, or trachea.
The trachea has a framework of smooth muscle with about 16 to 20 open rings of cartilage shaped like a C. These rings give rigidity to the trachea and ensure that it remains open. The opening to the trachea is a slitlike structure called the glottis. A thin flap of tissue called the epiglottis folds over the opening during swallowing and prevents food from entering the trachea.
At the upper end of the trachea, several folds of cartilage form the larynx, or voice box. In the larynx, flaplike pairs of tissues called vocal cords vibrate when a person exhales and produce sounds. At its lower end, the trachea branches into two large bronchi (singular, bronchus). These tubes also have smooth muscle and cartilage rings.
The bronchi branch into smaller bronchioles, forming a bronchial “tree.” The bronchioles terminate in the alveoli. Lungs Human lungs are composed of approximately 300 million alveoli. Red blood cells pass through the capillaries in single file, and oxygen from each alveolus enters the red blood cells and binds to the hemoglobin. In addition, carbon dioxide contained in the plasma and red blood cells leaves the capillaries and enters the alveoli when a breath is taken.
Most carbon dioxide reaches the alveoli as bicarbonate ions, and about 25 percent of it is bound loosely to hemoglobin. When a person inhales, the rib muscles and diaphragm contract, thereby increasing the volume of the chest cavity. This increase leads to reduced air pressure in the chest cavity, and air rushes into the alveoli, forcing them to expand and fill. The lungs passively obtain air from the environment by this process.
During exhalation, the rib muscles and diaphragm relax, the chest cavity volume diminishes, and the internal air pressure increases. The compressed air forces the alveoli to close, and air flows out. The nerve activity that controls breathing arises from impulses transported by nerve fibers passing into the chest cavity and terminating at the rib muscles and diaphragm. These impulses are regulated by the amount of carbon dioxide in the blood: A high carbon dioxide concentration leads to an increased number of nerve impulses and a more rapid breathing rate.
Respiratory Emergencies Emergencies may require you to assess and treat patients with malfunction of, or damage to, the respiratory system. Respiratory system conditions can also affect your treatment plan during other types of emergencies. Common Emergencies and Conditions Here is a brief description of the most common respiratory emergencies and conditions you may encounter. Make sure you know how to identify and treat all of them. Refer to other sources, such as your textbook, for complete information. Carbon Dioxide Retention and Hypoxic Drive Carbon dioxide retention can occur due to various types of lung diseases, most commonly COPD. COPD can alter the patient’s drive to breathe.
Normally when carbon dioxide levels increase, it triggers a person to breathe deeper and faster. In people who have chronically high levels of carbon dioxide, the body gets used to the high levels and instead begins to base the drive to breathe on low oxygen levels. This is referred to as hypoxic drive. Dyspnea Dyspnea is shortness of breath that can occur for a variety of reasons.
Respiratory illnesses, such as asthma and COPD, can lead to dyspnea. Additional causes of dyspnea include pulmonary edema, airway obstruction, and anxiety.
Symptoms include shallow, rapid breathing and anxiety. Treatment is often aimed at the underlying cause. Airway Infection (Upper and Lower) Airway infections can occur due to a variety of conditions such as croup, Respiratory Syncytial Virus (RSV), and pneumonia. An infection can affect the lower or upper airways. Symptoms may include wheezing, shortness of breath, and cough. Treatment will depend on the cause, but may include bronchodilators, steroids, and oxygen.
Respiratory System Diseases
Acute Pulmonary Edema Pulmonary edema is excess fluid on the lungs. It can occur suddenly due to congestive heart failure. Symptoms include shortness of breath, pink, frothy sputum, and a cough. The patient may also have crackles. Oxygen and the medication Lasix (furosemide) are typical treatments. COPD COPD, or chronic obstructive pulmonary disease, is caused by damage to the alveoli and is often due to smoking.
Symptoms may include wheezing, shortness of breath, and coughing. Treatment can include bronchodilators, steroids, and oxygen. Asthma and Hay Fever Asthma is a chronic condition that can cause increased mucus production, inflammation of the airways, and airway constriction. Symptoms may include wheezing, cough, and dyspnea. Hay fever is an allergic reaction to an allergen. Symptoms may include sneezing, cough, and runny nose. Asthma may be treated with bronchodilators and steroids.
Hay fever may be treated with antihistamines and decongestants. Anaphylaxis Anaphylaxis is a severe allergic reaction to an allergen.
The condition can be life-threatening, since it can lead to airway swelling and a drop in blood pressure. Symptoms can include trouble breathing, stridor, and hives. Treatment includes epinephrine and airway management.
Spontaneous Pneumothorax A pneumothorax involves air in the pleural space. It can occur spontaneously due to a lung infection or for unknown reasons.
Review Guide Respiratory System Biology Corner Answer Key
Symptoms include chest pain, dyspnea, and decreased breath sounds over the affected area. Treatment includes inserting a chest tube to remove the air. Pleural Effusion A pleural effusion involves an accumulation of fluid outside the lungs in the pleural space. It can occur due to an infection, congestive heart failure, and cancer. Symptoms include shortness of breath and decreased breath sounds over the affected area.
Review Guide Respiratory System
Treatment involves removal of the fluid in a procedure that must be performed at the hospital. Prehospital management involves keeping the patient comfortable and administering supplemental oxygen, if the patient is hypoxic. Pulmonary Embolism A pulmonary embolism is a blood clot in the lung. The clot usually travels from another part of the body, such as the legs. It can restrict blood flow to the lungs, decrease oxygen levels in the body, and be life-threatening. Symptoms can include dyspnea, tachycardia, and hypoxia. Administration of blood thinners at the hospital is the usual treatment.
Hyperventilation Hyperventilation is an abnormally high respiratory rate. Causes may include pain, anxiety, and fever. Treatment involves addressing the underlying cause. Environmental/Industrial Contaminants Environmental and industrial contaminants can involve the inhalation of various chemicals, substances, and gases that irritate the airway, such as carbon monoxide. Symptoms can include coughing, dyspnea, and an altered level of consciousness. Treatment includes administration of supplemental oxygen and airway management.
Foreign Body Aspiration Foreign body aspiration is the inhalation of something, such as food or an object. Symptoms include shortness of breath and stridor. Treatment may involve removing the foreign body at the hospital. Prehospital treatment includes airway management and supportive care. Tracheostomy Dysfunction Patients who have a tracheostomy tube can experience various complications, such as mucus plugs blocking the airway, bleeding, and dislodgment of the tube. Symptoms can include a blocked airway, cyanosis, and hypoxia.
Treatment depends on the complication. For example, an airway obstruction due to a mucus plug can be treated by suctioning the tube and changing the inner cannula of the trach.
Cystic Fibrosis Cystic fibrosis is a chronic disease that is inherited. It affects the digestive system and the lungs. Symptoms include excessive mucus production, wheezing, and dyspnea. Treatment by the prehospital provider includes medication to loosen mucus, suctioning, and oxygen. Terms/Concepts to Know: chronic obstructive pulmonary disease, status asthmaticus, bronchodilators, croup, epiglottitis, emphysema, allergen, RSV, bronchiolitis Other Emergency Respiratory Care Respiratory emergencies may require other types of treatment. Be sure you thoroughly understand the procedures and indications for use of these types of respiratory emergency equipment.
Metered-Dose Inhaler Metered-dose inhalers are small spray canisters, which can be used to deliver respiratory medications to the lungs. Bronchodilators, which open the airways, as well as steroids that decrease inflammation, can be administered via a metered-dose inhaler. Small-Volume Nebulizer A small volume nebulizer can also be used to deliver respiratory medication through a fine mist that the patient inhales. The most common medication delivered in a small volume nebulizer is Albuterol, which is a bronchodilator used to treat conditions such as asthma and COPD.