A 58-year-old patient with a long history of cigarette smoking presents with a chronic productive cough and recurrent lower respiratory tract infections. Bronchial biopsy shows impaired clearance of mucus and trapped particulate matter along the airway epithelium. Damage to which cellular structure most directly explains this finding?
Microvilli
Flagella
Cilia
Desmosomes
Tight junctions
The Correct Answer is C
A. Microvilli: Microvilli are small, finger-like projections on the apical surface of epithelial cells that increase surface area for absorption and secretion. They are abundant in the intestines and kidney tubules but do not play a primary role in clearing mucus or trapped particles from the respiratory tract.
B. Flagella: Flagella are long, whip-like structures used for motility in certain single-celled organisms, such as sperm cells or bacteria. Human respiratory epithelial cells do not possess flagella, so they are not involved in airway mucus clearance.
C. Cilia: Cilia are hair-like projections on the apical surface of respiratory epithelial cells that beat in a coordinated manner to move mucus, trapped dust, and pathogens toward the pharynx for clearance. Chronic cigarette smoking damages ciliary structure and function, impairing mucociliary clearance and leading to mucus accumulation, chronic productive cough, and recurrent infections.
D. Desmosomes: Desmosomes are intercellular junctions that provide mechanical adhesion between epithelial cells. While important for tissue integrity, they do not facilitate movement of mucus or debris along the airway epithelium.
E. Tight junctions: Tight junctions are specialized connections between epithelial cells that prevent paracellular leakage of fluids and solutes. They maintain barrier function but are not involved in the active transport of mucus or particulate matter along the respiratory tract.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
The COVID-19 virus, scientifically known as SARS-CoV-2, is an RNA virus, not a DNA virus. Its genetic material consists of single-stranded positive-sense RNA, which serves as a template for viral replication and protein synthesis inside host cells. RNA viruses generally have higher mutation rates than DNA viruses due to the lack of proofreading mechanisms during replication. Understanding the RNA-based genome of SARS-CoV-2 is crucial for developing diagnostic tests, vaccines, and antiviral therapies. Classifying it correctly as an RNA virus also distinguishes it from DNA viruses, which replicate using DNA as their genetic material and follow different replication strategies.
Correct Answer is B
Explanation
A. Flagella: Flagella are whip-like appendages that provide motility to bacteria, allowing them to move toward nutrients or away from harmful environments. While motility can contribute to colonization, flagella do not provide a protective barrier against phagocytosis or immune system attack.
B. Capsule: The capsule is an external polysaccharide or protein layer that surrounds the bacterial cell wall. It prevents recognition and ingestion by phagocytes, inhibits complement activation, and contributes to increased virulence. Encapsulated bacteria, such as Streptococcus pneumoniae, are particularly problematic in patients with weakened immune systems, like those with chronic alcoholism, because the capsule impedes effective immune clearance.
C. Fimbriae: Fimbriae are short, hair-like projections on the bacterial surface that facilitate attachment to host cells and surfaces. They play a role in colonization and biofilm formation but do not directly prevent phagocytosis or enhance survival against immune defenses.
D. Lipopolysaccharide: Lipopolysaccharide (LPS) is a component of the outer membrane of Gram-negative bacteria that contributes to endotoxin activity, triggering inflammation and septic shock. While LPS can affect host immune responses, it does not provide a direct physical barrier to phagocytosis.
E. Peptidoglycan: Peptidoglycan forms the rigid structural layer of the bacterial cell wall, providing shape and protection against osmotic pressure. Although essential for bacterial integrity, peptidoglycan does not prevent immune recognition or phagocytosis in the way that a capsule does.
Whether you are a student looking to ace your exams or a practicing nurse seeking to enhance your expertise , our nursing education contents will empower you with the confidence and competence to make a difference in the lives of patients and become a respected leader in the healthcare field.
Visit Naxlex, invest in your future and unlock endless possibilities with our unparalleled nursing education contents today
Report Wrong Answer on the Current Question
Do you disagree with the answer? If yes, what is your expected answer? Explain.
Kindly be descriptive with the issue you are facing.