Why does erythema (redness) occur when a person experiences a bone fracture?
The lymphatic system absorbs an increased amount of fluid.
Increased vasodilation brings more blood to the injury site.
The inflammatory process increases capillary permeability.
The immune system blocks lymphatic drainage in the body.
The Correct Answer is B
Choice A rationale
While the lymphatic system is involved in managing interstitial fluid, erythema is specifically a vascular phenomenon. The lymphatic system's primary role after an injury is to drain the excess fluid and debris that accumulate in the tissues, which helps reduce edema (swelling) rather than causing the red color. Erythema is caused by an increase in the volume of oxygenated blood in the superficial dermis, which is not a function of the lymphatic vessels.
Choice B rationale
Following a bone fracture, the body initiates an acute inflammatory response. Damaged mast cells and platelets release chemical mediators like histamine and bradykinin. These substances cause local vasodilation, which is the widening of the blood vessels at the injury site. This increased blood flow, known as hyperemia, brings essential white blood cells and nutrients to the area to begin the repair process. The surge of red, oxygenated blood near the skin surface produces erythema.
Choice C rationale
Increased capillary permeability is indeed a part of the inflammatory process, but it is primarily responsible for the development of edema, not erythema. When capillaries become "leaky," protein-rich fluid escapes into the interstitial space, causing tissue swelling. Erythema is specifically defined by the redness of the skin, which is the direct result of vasodilation and increased blood flow to the area, whereas permeability changes focus on the movement of fluid out of the vessels.
Choice D rationale
The immune system does not typically block lymphatic drainage as a standard response to a fracture. In fact, an efficient lymphatic system is necessary to clear the inflammatory exudate. If the lymphatic system were blocked, it would lead to severe, localized lymphedema, but it would not be the primary cause of the redness seen immediately after an injury. Erythema is an active process of bringing blood to the site, not a passive result of blocked drainage.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is C
Explanation
Choice A rationale
Circulation refers to the movement of blood through the heart and blood vessels to deliver nutrients and oxygen to tissues while removing waste products. While circulation is necessary to transport gases throughout the body, it is the systemic movement of fluid rather than the specific process of gas crossing membranes. Circulation relies on the pumping action of the heart to move the oxygenated blood that was created during gas exchange.
Choice B rationale
Ventilation is the mechanical process of moving air into and out of the lungs. It involves the physical acts of inhalation and exhalation, driven by the diaphragm and intercostal muscles. Ventilation ensures that oxygen is brought into the alveoli and carbon dioxide is removed from them, but it does not describe the movement of these gases across the respiratory membrane into the blood or cells themselves.
Choice C rationale
Gas exchange is the biological process where oxygen molecules move from the air in the alveoli into the blood, and carbon dioxide moves from the blood into the alveoli. This occurs via passive diffusion across the alveolar-capillary membrane. Additionally, internal gas exchange occurs at the cellular level, where oxygen moves into cells for metabolism and carbon dioxide enters the blood to be transported back to the lungs for elimination.
Choice D rationale
Bronchodilation is the expansion of the bronchial air passages, usually caused by the relaxation of the smooth muscles in the airway walls. This process decreases airway resistance and increases the volume of air that can reach the alveoli during ventilation. While it facilitates better airflow, it is a structural change in the airways rather than the actual transport of oxygen and carbon dioxide across the blood and cellular barriers.
Correct Answer is C
Explanation
Choice A rationale
Tetany is a condition characterized by involuntary muscle contractions and is caused by hypocalcemia, or low serum calcium levels below 8.5 mg/dL. Hyperparathyroidism involves the overproduction of parathyroid hormone, which increases bone resorption and renal calcium reabsorption, leading to hypercalcemia. Therefore, tetany would not occur in hyperparathyroidism; instead, it is a hallmark sign of hypoparathyroidism where calcium levels are insufficient to maintain normal neuromuscular stability and resting potentials.
Choice B rationale
Tingling in the fingers, or paresthesia, is another classic symptom of hypocalcemia. Since hyperparathyroidism causes the serum calcium to rise above the normal range of 8.5 to 10.5 mg/dL, the nerves become less excitable, not more. Tingling and numbness are signs of increased neuromuscular irritability associated with low calcium. In hyperparathyroidism, the patient is more likely to experience muscle weakness, lethargy, and diminished deep tendon reflexes due to the high calcium levels.
Choice C rationale
Hyperparathyroidism leads to excessive secretion of parathyroid hormone, which pulls calcium out of the bones and into the blood. This results in hypercalcemia, with serum levels often exceeding 10.5 mg/dL. As the kidneys attempt to filter this excess calcium, the concentration of calcium in the urine increases, known as hypercalciuria. This high urinary calcium concentration significantly increases the risk of forming calcium-based renal calculi, or kidney stones, within the urinary tract.
Choice D rationale
Diarrhea is not a typical complication of hyperparathyroidism. In fact, hypercalcemia caused by high parathyroid hormone levels usually leads to decreased gastrointestinal motility. This occurs because high calcium levels interfere with the smooth muscle contractions of the digestive tract. Consequently, patients with hyperparathyroidism are much more likely to suffer from constipation rather than diarrhea. Diarrhea is usually related to other metabolic or infectious processes unrelated to parathyroid overactivity.
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