Nokea
In the process of renal autoregulation,
- A. the loop of Henle reabsorbs more sodium and chloride ions
- B. the collecting tubule reabsorbs less water
- C. the afferent arterioles dilate, increasing glomerular filtration rate
- D. the efferent arterioles dilate, allowing blood to flow through the kidney faster
Correct Answer: B
Rationale: Step-by-step rationale for choice B being correct:
1. Renal autoregulation maintains a constant glomerular filtration rate (GFR).
2. If the collecting tubule reabsorbs less water, it helps regulate the body's fluid balance.
3. Reabsorbing less water in the collecting tubule helps prevent excessive fluid loss or retention.
4. This process ensures that the body maintains appropriate blood volume and blood pressure.
Summary of why other choices are incorrect:
A: Loop of Henle reabsorbs ions, not more sodium and chloride ions.
C: Afferent arterioles constrict to decrease GFR, not dilate to increase it.
D: Efferent arterioles constrict to maintain GFR, not dilate to allow faster blood flow.
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________ is not normally found in urine, and its presence may indicate a problem with the kidneys.
- A. Albumin
- B. Bilirubin
- C. Ammonium
- D. Urea
Correct Answer: A
Rationale: The correct answer is A: Albumin. Albumin is a protein normally found in blood but not in urine. Its presence in urine, known as proteinuria, may indicate a problem with the kidneys such as kidney damage or dysfunction in filtering blood. Bilirubin (B) is a product of red blood cell breakdown and its presence in urine indicates liver or bile duct issues. Ammonium (C) is a normal byproduct of protein metabolism and is excreted in urine. Urea (D) is a waste product of protein metabolism and is normally found in urine.
The main reason for the use of combination therapy in the drug treatment of Tuberculosis is:
- A. Reduce the incidence of side effects
- B. Delay or prevent the emergence of resistance
- C. Synergistically increase antimycobacterial activity
- D. Provide prophylaxis against other bacterial infections
Correct Answer: B
Rationale: The main reason for using combination therapy in TB treatment is to delay or prevent the emergence of resistance. Step 1: TB is caused by Mycobacterium tuberculosis, which has a high mutation rate leading to drug resistance. Step 2: With combination therapy, multiple drugs target different aspects of the bacteria's lifecycle, making it harder for resistance to develop. Step 3: This approach ensures that if one drug becomes ineffective due to resistance, others can still be effective. Summary: Choice B is correct as it directly addresses the issue of resistance, which is a critical concern in TB treatment. Choices A, C, and D are incorrect because reducing side effects, increasing antimycobacterial activity, and providing prophylaxis against other bacterial infections are not the primary reasons for using combination therapy in TB.
Which of the following drug that acts by inhibiting HIV protease enzyme?
- A. Lamivudine
- B. Efavirenz
- C. Stavudine
- D. Ritonavir
Correct Answer: D
Rationale: Rationale:
1. Ritonavir is a protease inhibitor used in HIV treatment.
2. It works by inhibiting the HIV protease enzyme, preventing viral replication.
3. Lamivudine, Efavirenz, and Stavudine are not protease inhibitors but work through different mechanisms.
4. Lamivudine is a nucleoside reverse transcriptase inhibitor, Efavirenz is a non-nucleoside reverse transcriptase inhibitor, and Stavudine is another nucleoside reverse transcriptase inhibitor.
Summary:
Ritonavir is the correct answer as it directly targets the HIV protease enzyme, unlike the other options which act on reverse transcriptase enzymes.
An adhesion of the prepuce to the head of the penis, making it impossible to retract, is:
- A. Paraphimosis
- B. Phimosis
- C. Smegma
- D. Dyschezia
Correct Answer: B
Rationale: The correct answer is B: Phimosis. Phimosis is the adhesion of the prepuce to the head of the penis, leading to the inability to retract the foreskin. This condition can cause pain, difficulty urinating, and increased risk of infections. Paraphimosis (choice A) is the painful retraction of a foreskin that is stuck behind the glans. Smegma (choice C) is a buildup of dead skin cells and oils under the foreskin. Dyschezia (choice D) is difficulty in passing stools. In this case, phimosis best describes the situation of adhesion preventing foreskin retraction.
Regarding renal colic secondary to calculi:
- A. Females are more commonly affected than males
- B. 50% of calculi are radio-opaque
- C. It may present without haematuria
- D. There is a 20% chance of recurrence by 5 years
Correct Answer: C
Rationale: The correct answer is C because renal colic can present without hematuria. Renal colic is typically associated with severe flank pain caused by ureteral stones. Hematuria is a common symptom but not always present. This is due to the stone's location and size affecting the degree of irritation and damage to the urinary tract. Therefore, the absence of hematuria does not exclude the possibility of renal colic. Choices A, B, and D are incorrect. Females are not more commonly affected than males, calculi can be either radio-opaque or radio-lucent, and the recurrence rate by 5 years is closer to 50% rather than 20%.