Respiratory Flashcards
Q1: List distinguishing histological differences between respiratory epithelium and olfactory epithelium
Both have pseudostratified columnar epithelium. Only olfactory tissue has Bowman’s glands. Only respiratory epithelium has goblet cells.
Q2: What is the significance of the different types of epithelium on the false and true vocal cords?
A common place for laryngeal cancer formation. Similarly to other places of epithelial transition, this area is also susceptible for cancer.
Q3: What is another name for this tissue (pseudostratified columnar epithelium with goblet cells)?
Respiratory epithelium
Q4: Where is the trachealis muscle located AND what is its function?
smooth or skeletal?
Trachealis muscle is an example of smooth muscle. It bridges the gap between free ends of C-shaped cartilages at the posterior border of the trachea, adjacent to the esophagus.
A primary function of the trachealis is to constrict the windpipe, allowing air to be expelled with more force e.g. during coughing.
Q5: What type of blood is carried by the large, thin-walled vs. smaller arteries?
De-oxygenated blood is carried by the thin walled pulmonary arteries, reflecting low blood pressure. Oxygenated blood is carried by the bronchial arteries that have regular wall thickness, similar to other arteries of the high-pressure system.
Q6: What could be the cause of the changes?
Inflammation and emphysema. Emphysema is a pathologic condition of the lung defined as abnormal “Emphysema airspaces”. FYI: It is characterized by permanent enlargement of air spaces distal to the terminal bronchioles due to destruction of alveolar walls, and is without fibrosis. The sample was likely taken from a smoker. This sample represents the beginning stage, a more advanced stage of emphysema is represented by EVMS slide 707.
Q7: What are the components of the blood-air barrier (image)?
Listed from the “blood side”: endothelium, basal lamina, epithelium
Q8: Where do you find elastic fibers and what are their functions?
Elastic fibers are found in the larger blood vessels and the parenchyma of the lung, including alveolar walls. The mechanical properties of the lung are largely determined by the connective tissue networks laid down during development. The macromolecules most important for lung mechanics and structural integrity are collagen, elastin, and proteoglycans. Members of the fibrillar collagen gene family provide the structural framework of the various lung compartments and elastic fibers provide elastic recoil. Elastin is also an important architectural component that influences lung development, predominantly during the alveolar stage. Elastin degradation is a key step in the pathogenesis of chronic obstructive pulmonary disease. Exacerbating the disease process is the inability of lung cells to repair damaged elastic fibers, which leads to permanently compromised lung function and ongoing degenerative disease.
Q9: How do you distinguish between a small bronchus and a bronchiole?
Small bronchi will still have some hyaline cartilage present, while bronchioles will not.
Q10: Where will Clara cells be found and what is their function?
Clara cells are dome-shaped cells with short microvilli found in the small airways, bronchioles of the lungs. Clara cells are found in the ciliated simple epithelium. These cells may secrete glycosaminoglycans to protect the bronchiole lining. Clara cells gradually increase in number as the number of goblet cells decrease.
One of the main functions of Clara cells is to protect the bronchiolar epithelium. They do this by secreting a small variety of products, including Clara cell secretory protein (CCSP) and a solution similar to the component of the lung surfactant. They are also responsible for detoxifying harmful substances inhaled into the lungs. Clara cells accomplish this with cytochrome P450 enzymes found in their smooth endoplasmic reticulum. Clara cells also act as a stem cell and multiply and differentiate into ciliated cells to regenerate the bronchiolar epithelium.
Q11: Which cells produce surfactant, & explain what it does.
Pulmonary surfactant is a surface-active lipoprotein complex (phospholipoprotein) formed by type II alveolar cells. The proteins and lipids that comprise the surfactant have both a hydrophilic region and a hydrophobic region. By adsorbing to the air-water interface of alveoli with the hydrophilic head groups in the water and the hydrophobic tails facing towards the air, the main lipid component of surfactant, dipalmitoylphosphatidylcholine, (DPPC), reduces surface tension, thereby increasing pulmonary compliance.
