Chapter 10. Lung and Respiratory Tract. Flashcards
Acute respiratory distress syndrome (ARDS)
A disorder in which damage to alveoli throughout the lungs causes edema and leads to respiratory failure. Referred to clinically as “acute lung injury.”
Affects approximately 190,000 patients per year in the United States.
Characterized by rapid onset of life-threatening respiratory insufficiency, cyanosis. and severe arterial hypoxemia.
It may occur in association with primary pulmonary diseases or systemic inflammatory disorders.
The histologic manifestation is diffuse alveolar damage.
Alveolus (pl., alveoli)
Any of the many tiny air sacs of the lungs which allow for rapid gaseous exchange.
Edema
An abnormal excess accumulation of serous fluid in connective tissue or in a serous cavity. Also called “dropsy.”
Cyanosis
A bluish discoloration of the skin resulting from poor circulation or inadequate oxygenation of the blood.
Hypoxemia
An abnormally low concentration of oxygen in the blood.
Serous fluid (i.e., from the serum)
Of, resembling, or producing serum. A clear to pale yellow watery fluid that is found in the body especially in the spaces between organs and the membranes which line or enclose them (such as the heart and pericardium or abdomen and peritoneum) and that when occurring in large quantities is indicative of a pathological condition (such as cirrhosis or heart failure) or surgical complication.
Aspiration
A condition in which food, liquids, saliva, or vomit is breathed into the airways.
Hemorrhage
The release of blood from a broken blood vessel, either inside or outside the body.
Hyaline membranes
Consist of fibrin-rich edema fluid mixed with debris from necrotic epithelial cells.
Obstructive (airway) disease
A chronic disease that decreases pulmonary gas exchange and that is characterized by an increase in resistance to air flow caused by partial or complete airway obstruction at any level.
In obstructive diseases, the forced vital capacity (FVC) is normal or slightly decreased, whereas the expiratory flow rate, usually measured as the forced expiratory volume at 1 second (FEV1), is significantly decreased. Thus, the ratio of FEV to FVC is decreased.
Restrictive disease
A chronic disease that decreases pulmonary gas exchange and that is characterized by reduced expansion of the lung parenchyma and decreased total lung capacity.
The forced vital capacity (FVC) is reduced and the expiratory flow rate is normal or reduced proportionately. Hence, the ratio of FEV to FVC is near normal.
Forced vital capacity (FVC)
The total volume of air that can be forcibly expired after a maximal inspiration.
Forced expiratory volume at 1 second (FEV1)
The volume of air that can be forcibly expired in the first second.
Expiratory flow rate
Usually measured as the forced expiratory volume at 1 second (FEV1).
What are the three major obstructive lung disorders?
Emphysema, chronic bronchitis, and asthma.
Chronic obstructive pulmonary disease (COPD)
Characterized by obstructive airway and alveolar abnormalities caused by inhalation of noxious particles or gases, most often due to smoking tobacco.
Affects more than 5% of the adults in the United States, where it is the third leading cause of death, exceeded only by cardiovascular disease and cancer.
Chronic bronchitis
A chronic obstructive pulmonary disease (COPD) that is a mechanical obstruction of the airways by mucus secretions and fibrosis.
Defined by the presence of a persistent productive cough for at least three consecutive months in at least two consecutive years.
Emphysema
A chronic obstructive pulmonary disease (COPD) that is a function obstruction of the airways due to parenchymal destruction.
Defined by the presence of enlarged air spaces distal to the terminal bronchioles and the destruction of alveolar walls.
Fibrosis
Fibrosis, also known as fibrotic scarring, is a pathological wound healing in which connective tissue replaces normal parenchymal tissue to the extent that it goes unchecked, leading to considerable tissue remodeling and the formation of permanent scar tissue.
Repeated injuries, chronic inflammation and repair are susceptible to fibrosis where an accidental excessive accumulation of extracellular matrix components, such as the collagen is produced by fibroblasts, leading to the formation of a permanent fibrotic scar.
Distal
Situated away from the center of the body or from the point of attachment.
What are the factors that influence the development and severity of bronchitis and emphysema?
- Inhalation of noxious particles, such as toxins and carcinogens, and damage cells directly and induce deleterious reactive changes (e.g., hypertrophy of mucous glands and proliferation of goblet cells).
- Inflammation resulting from cell injury caused by toxic effects of inhaled agents.
- Proteases released from neutrophils are thought to have a central role in the emphysematous changes that accompany COPD.
- Microbial infection is often present but has a secondary role, chiefly by maintaining inflammation and exacerbating symptoms.
Radial traction
The connective tissue that surrounds the airways of the lungs are called the parenchyma. This forms a sort of scaffold around the airways, keeping them open with a force known as “radial traction”. As inspiration takes place, the traction increases as the fibers that make the parenchyma are stretched.
Centriacinar (centrilobular) emphysema
The term centrilobular means that the disease occurs in the center of the functional units of the lungs, called the secondary pulmonary lobules.
Occurs with loss of the respiratory bronchioles in the proximal portion of the acinus, with sparing of distal alveoli. This pattern is most typical for smokers.
Panacinar (panlobular) emphysema
Involves all lung fields, particularly the bases. Occurs with loss of all portions of the acinus from the respiratory bronchiole to the alveoli. This pattern is typical for alpha-1-antitrypsin deficiency.
