Select the response that most accurately describes the pathophysiology of multiple sclerosis.
Loss of myelin in the central nervous system leads to nerve damage
Decreased dopamine levels lead to improved neurologic functioning
Decreased acetylcholine causes destruction of dendrites
Increased levels of serotonin result in overgrowth of gray matter
The Correct Answer is A
A. Loss of myelin in the central nervous system leads to nerve damage. : This autoimmune disorder involves the T-cell mediated destruction of oligodendrocytes and the protective fatty sheath surrounding axons. Demyelination results in impaired saltatory conduction and eventual axonal degeneration. It creates sclerotic plaques within the white matter.
B. Decreased dopamine levels lead to improved neurologic functioning. : Lowered dopamine concentrations in the nigrostriatal pathway are the pathological basis for motor deficits in Parkinson's disease. This neurochemical depletion impairs rather than improves functional capacity. It is not the mechanism for multiple sclerosis.
C. Decreased acetylcholine causes destruction of dendrites. : Acetylcholine deficiency is primarily associated with the cognitive decline seen in Alzheimer's disease. While neurotransmitter imbalances occur in many conditions, they do not cause the primary inflammatory demyelination seen here. It is not a demyelinating process.
D. Increased levels of serotonin result in overgrowth of gray matter. : Serotonin is an indolamine primarily regulating mood, sleep, and appetite rather than structural gray matter volume. Multiple sclerosis is characterized by tissue atrophy and scarring rather than overgrowth. It affects white matter more than gray matter.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is C
Explanation
A. gastroesophageal reflux.: This typically presents as retrosternal burning or pyrosis that may worsen when lying supine. While high-fat meals can trigger it, the pain is usually midline and substernal. It does not typically localize to the right upper quadrant.
B. appendicitis.: This inflammatory process begins with periumbilical pain that subsequently migrates to the right lower quadrant at McBurney's point. It is not triggered by the ingestion of fatty foods or biliary stimulation. The anatomical location is inferior to the RUQ.
C. cholecystitis.: Ingestion of lipids triggers cholecystokinin release, causing gallbladder contraction against an obstructing stone. This results in visceral pain in the right upper quadrant that often radiates to the right scapula. Normal cardiac findings support a biliary etiology.
D. a myocardial infarction.: While inferior wall MI can present with epigastric pain, a normal electrocardiogram makes this diagnosis less likely in an acute setting. The specific trigger of high-fat meals and RUQ localization points toward a gallbladder pathology. It is a cardiac emergency.
Correct Answer is B
Explanation
A. Casual contact: This virus is not transmitted through hugging, kissing, or sharing utensils with an infected individual. It requires direct contact with specific bodily fluids to penetrate the host. Environmental stability does not facilitate transmission through social interaction.
B. Exposure to infected blood: This hepadnavirus is primarily transmitted through percutaneous or mucosal exposure to viremic blood or serum. It is common in intravenous drug use, needle-stick injuries, and blood transfusions. It remains a major occupational hazard for healthcare workers.
C. Respiratory droplets: This mode of transmission is characteristic of pulmonary pathogens like influenza or Mycobacterium tuberculosis. Hepatitis B does not replicate in the respiratory epithelium or aerosolize during coughing. It is not an airborne or droplet-borne infection.
D. Contaminated food or water: This describes the fecal-oral route of transmission typical of Hepatitis A and E viruses. Hepatitis B is not an enteric virus and is inactivated by the acidic environment of the stomach. It is not associated with sanitation.
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