A 55-year-old male with a 30-year history of smoking is examined for respiratory disturbance. Examination of his airway (bronchial) reveals that stratified squamous epithelial cells have replaced the normal columnar ciliated cells. This type of cellular adaptation is called:
Hyperplasia
Dysplasia
Metaplasia
Hypertrophy
The Correct Answer is C
Choice A Reason:
Hyperplasia refers to an increase in the number of cells in an organ or tissue, usually resulting in an increase in the size of the organ or tissue. This process is often a response to a stimulus and can be physiological or pathological. However, hyperplasia does not involve the replacement of one cell type with another, as seen in this case.
Choice B Reason:
Dysplasia is characterized by abnormal growth and development of cells within tissues or organs. It often indicates a precancerous condition and involves changes in cell size, shape, and organization. While dysplasia can occur in the respiratory tract, it does not describe the replacement of one type of epithelial cell with another.
Choice C Reason:
This is the correct answer. Metaplasia is the process by which one type of adult cell is replaced by another type of adult cell that is not typical for that tissue. In this case, the normal columnar ciliated cells in the bronchial airway have been replaced by stratified squamous epithelial cells, a common adaptation in response to chronic irritation from smoking.
Choice D Reason:
Hypertrophy refers to an increase in the size of cells, leading to an increase in the size of the affected organ or tissue. This process does not involve a change in cell type, making it an incorrect choice for this scenario.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
Choice A Reason:
Norepinephrine is a key neurotransmitter released by the sympathetic nervous system during the “fight-or-flight” response. It plays a crucial role in preparing the body to respond to stress by increasing heart rate, blood pressure, and blood flow to muscles, as well as dilating the airways. These physiological changes are essential for coping with acute stress.
Choice B Reason:
Cortisol is a hormone released by the adrenal glands in response to stress, but it is primarily associated with the hypothalamic-pituitary-adrenal (HPA) axis rather than the sympathetic nervous system. While cortisol contributes to the body’s overall stress response by increasing blood sugar levels and suppressing the immune system, it is not the primary mediator of the acute “fight-or-flight” response.
Choice C Reason:
ACTH (adrenocorticotropic hormone) is a hormone produced by the pituitary gland that stimulates the adrenal glands to release cortisol. It is part of the HPA axis and plays a role in the body’s long-term stress response, but it is not directly involved in the immediate activation of the sympathetic nervous system.
Choice D Reason:
Glucagon is a hormone produced by the pancreas that raises blood glucose levels by promoting the breakdown of glycogen to glucose in the liver. While it can be involved in the body’s response to stress by ensuring an adequate supply of glucose, it is not a primary mediator of the acute stress response mediated by the sympathetic nervous system.
Correct Answer is B
Explanation
Choice A Reason:
Increased neuromuscular excitability is not typically associated with respiratory acidosis. Instead, respiratory acidosis can lead to symptoms such as confusion, fatigue, and shortness of breath due to the buildup of carbon dioxide in the blood. Neuromuscular excitability is more commonly associated with conditions like hypocalcemia.
Choice B Reason:
This is the correct answer. Respiratory acidosis occurs when the lungs cannot remove enough carbon dioxide (CO2) from the body, leading to an accumulation of CO2 in the blood. This increase in CO2 results in the formation of carbonic acid, which lowers the pH of the blood. The elevated levels of carbonic acid are a hallmark of respiratory acidosis.
Choice C Reason:
Increased pH is not associated with respiratory acidosis. In fact, respiratory acidosis is characterized by a decrease in blood pH due to the accumulation of carbon dioxide and the subsequent increase in carbonic acid. Therefore, this choice is incorrect.
Choice D Reason:
Hypokalemia, or low potassium levels, is not typically associated with respiratory acidosis. Instead, respiratory acidosis can sometimes lead to hyperkalemia (high potassium levels) due to the shift of potassium out of cells in response to the acidotic state. Therefore, this choice is incorrect.
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