Sickle cell anemia is caused by an inherited recessive gene found more commonly in those of _______ descent.
Western European
Native American
African
Asian
The Correct Answer is C
A. Western European is incorrect because sickle cell anemia is rare among individuals of Western European descent. While carriers exist, the prevalence is much lower than in populations of African ancestry.
B. Native American is incorrect because sickle cell anemia is uncommon in Native American populations. Other hemoglobinopathies, like thalassemia, may be more prevalent in specific indigenous groups.
C. African is correct because sickle cell anemia is caused by a recessive mutation in the HBB gene, which affects the beta chain of hemoglobin. This mutation leads to the production of abnormal hemoglobin S, causing red blood cells to adopt a sickle shape under low oxygen conditions. Sickle-shaped cells are rigid, sticky, and prone to hemolysis, leading to anemia, vaso-occlusive crises, and organ damage. The gene is more commonly found in individuals of African descent, as heterozygosity (carriers) provides some protection against malaria, which historically explains the high prevalence in Africa.
D. Asian is incorrect because sickle cell anemia is relatively rare in Asian populations. Other hemoglobin disorders, such as thalassemia, are more common in Southeast Asian and Mediterranean populations.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
A. Bacterial overgrowth of highly contagious S. aureus with development of vesicles and pruritus is incorrect because this description applies to impetigo, which is a superficial bacterial skin infection. Psoriasis is an autoimmune condition and is not contagious, so bacteria are not the primary cause.
B. Abnormal T-cell activation leading to excessive growth of keratinocytes and rapid epidermal shedding is correct because psoriasis is driven by dysregulation of the immune system. In this condition, T-cells become overactive and release cytokines that stimulate keratinocyte proliferation at an accelerated rate. Normally, keratinocytes take about 28–30 days to mature and shed, but in psoriasis, this process can occur in 3–5 days. The rapid turnover results in thickened, scaly plaques, redness, and inflammation. Chronic inflammation also contributes to the pruritus, discomfort, and erythema seen in affected areas. Triggers such as stress, infections, or certain medications may exacerbate the condition but do not cause it directly.
C. Sensitization on first exposure to an allergen with rash development on subsequent exposure is incorrect because this describes allergic contact dermatitis, where the immune system reacts to a previously encountered allergen. Psoriasis, in contrast, is autoimmune and does not require prior allergen exposure. The lesions are caused by internal immune dysregulation, not external sensitization.
D. Latent virus becomes reactivated by infection or stress, leading to development of skin lesions is incorrect because this mechanism describes viral conditions such as shingles (herpes zoster). Psoriasis is not caused by a virus, and the plaques and scales result from keratinocyte hyperproliferation due to immune dysregulation rather than viral reactivation.
Correct Answer is ["A","B","C","E"]
Explanation
A. Pallor is correct because anemia results in reduced red blood cell count or hemoglobin levels, which decreases the blood’s oxygen-carrying capacity. Pallor is most noticeable in areas where the skin is thin or highly vascularized, such as the face, conjunctiva, lips, nail beds, and mucous membranes. This is a classic and often early sign of anemia.
B. Fatigue is correct because tissues and organs receive less oxygen, which is necessary for cellular metabolism and energy production. The reduced oxygen delivery leads to muscle weakness, low endurance, and a persistent feeling of tiredness, even after rest. Fatigue is one of the most common and debilitating symptoms of anemia.
C. Dyspnea is correct because the body tries to compensate for the reduced oxygen-carrying capacity of the blood by increasing respiratory rate and depth. This can cause shortness of breath, especially during exertion or activity, as the lungs attempt to supply more oxygen to the tissues. Chronic anemia can also lead to exertional dyspnea at relatively low levels of activity.
D. Bradycardia is incorrect because anemia typically causes tachycardia, not bradycardia. The heart beats faster to maintain adequate oxygen delivery to vital organs when hemoglobin levels are low. Bradycardia would not be a compensatory response to anemia and may indicate a separate cardiac issue.
E. Dizziness is correct because the brain may receive insufficient oxygen, especially during sudden position changes or physical activity, leading to lightheadedness, vertigo, or fainting (syncope). Dizziness is a reflection of the central nervous system’s sensitivity to hypoxia caused by anemia.
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