What is the primary role of the sinoatrial (SA) node in the heart?

A. Pacemaker of the heart

B. Blood pressure regulation

C. Electrical conduction delay

D. Stimulating muscle contraction

Correct Answer: A
Rationale: The correct answer is A: Pacemaker of the heart. The SA node, known as the natural pacemaker, initiates the electrical impulses that set the rhythm for the heartbeat. It is responsible for coordinating the heart's contractions by generating electrical signals at regular intervals. Choice B is incorrect as the SA node's primary function is not related to blood pressure regulation. Choice C is incorrect as the SA node does not cause electrical conduction delay but rather initiates and conducts the electrical impulses. Choice D is incorrect as the SA node does not directly stimulate muscle contraction but rather initiates the electrical events that lead to muscle contraction.

After administering pantoprazole to a client with gastroesophageal reflux disease (GERD), which statement by the client indicates to the nurse that the medication is producing the desired effect?

• A. After eating my meal, I did not experience any heartburn
• B. I have a great appetite and am feeling really hungry
• C. I should increase the amount of vitamin C in my diet
• D. While eating, I had no difficulty swallowing any of the foods

Correct Answer: A
Rationale: The correct answer is A. Pantoprazole reduces stomach acid production, thus preventing the occurrence of heartburn after meals, which is a common symptom of GERD. Choice B is incorrect because an increased appetite and hunger are not indicators of the desired effect of pantoprazole. Choice C is unrelated to the medication's effect on GERD symptoms. Choice D is also incorrect because the absence of difficulty swallowing is not a specific indicator of pantoprazole's effectiveness in treating GERD.

Which disorder is characterized by demyelination of neurons in the central nervous system?

• A. Multiple sclerosis
• B. Parkinson's disease
• C. Alzheimer's disease
• D. Huntington's disease

Correct Answer: A
Rationale: Multiple sclerosis is the correct answer. It is an autoimmune disease that specifically targets and damages the myelin sheath surrounding neurons in the central nervous system. This demyelination disrupts the transmission of nerve signals and leads to a variety of neurological symptoms. Parkinson's disease (Choice B), Alzheimer's disease (Choice C), and Huntington's disease (Choice D) are neurodegenerative disorders that do not primarily involve demyelination of neurons in the CNS. Parkinson's disease is characterized by the loss of dopamine-producing neurons, Alzheimer's disease by the formation of plaques and tangles in the brain, and Huntington's disease by a genetic mutation affecting nerve cells.

What is the primary cause of diabetic ketoacidosis (DKA)?

• A. Insulin deficiency
• B. Overhydration
• C. Excess carbohydrate intake
• D. Excess insulin

Correct Answer: A
Rationale: The correct answer is A: Insulin deficiency. Diabetic ketoacidosis occurs due to a severe lack of insulin, causing the body to break down fat for energy, leading to the production of ketones and acidification of the blood. Option B, Overhydration, is incorrect as DKA is characterized by dehydration rather than overhydration. Option C, Excess carbohydrate intake, is incorrect because while high blood sugar levels can contribute to DKA, the primary cause is insulin deficiency. Option D, Excess insulin, is also incorrect as DKA is not caused by an excess of insulin but rather by a lack of it.

What is the priority intervention for a patient experiencing an acute asthma attack?

• A. Administering a bronchodilator
• B. Encouraging the patient to drink fluids
• C. Applying a high-flow oxygen mask
• D. Performing chest physiotherapy

Correct Answer: A
Rationale: Administering a bronchodilator is the priority intervention in an acute asthma attack. Bronchodilators help to quickly open the airways, relieve bronchospasm, and improve breathing. Encouraging the patient to drink fluids may be beneficial for other conditions but is not the priority in an acute asthma attack. Applying a high-flow oxygen mask may be necessary in severe cases of respiratory distress but is not the initial priority when managing an acute asthma attack. Performing chest physiotherapy is not indicated as the primary intervention for an acute asthma attack and may not address the immediate need to open the airways and improve breathing.