Nokea
The release of cortisol is stimulated by
- A. aldosterone
- B. angiotensin
- C. antidiuretic hormone (ADH)
- D. adrenocorticotropic hormone (ACTH)
Correct Answer: D
Rationale: The correct answer is D: adrenocorticotropic hormone (ACTH). ACTH is released by the pituitary gland in response to stress or low cortisol levels, stimulating the adrenal glands to release cortisol. Aldosterone (A) regulates electrolyte balance, angiotensin (B) regulates blood pressure, and antidiuretic hormone (C) regulates water balance, but they do not directly stimulate cortisol release. So, ACTH is the correct choice for stimulating cortisol production.
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A short-acting cycloplegic and mydriatic drug is:
- A. Atropine
- B. Homatropine
- C. Hyoscine
- D. Tropicamide
Correct Answer: D
Rationale: The correct answer is D: Tropicamide. Tropicamide is a short-acting cycloplegic and mydriatic drug commonly used in ophthalmology. It acts quickly, providing temporary dilation of the pupil and relaxation of the ciliary muscle for refraction assessment. Atropine (A) is a long-acting cycloplegic, not short-acting. Homatropine (B) and Hyoscine (C) are also longer-acting drugs compared to Tropicamide. Therefore, D is the correct answer for its rapid onset and short duration of action in dilating the pupil and paralyzing accommodation.
Insulin:
- A. binds to GLUT 1-5 receptors in the peripheral tissues
- B. deficiency results in increased gluconeogenesis
- C. has a plasma half-life of 2-3 hours
- D. is secreted by the pancreatic A cells
Correct Answer: B
Rationale: The correct answer is B because insulin deficiency leads to increased gluconeogenesis due to the lack of inhibition on glucose production. Choice A is incorrect as insulin binds to GLUT 4 receptors, not GLUT 1-5. Choice C is wrong because insulin's half-life is only a few minutes. Choice D is also inaccurate as insulin is secreted by pancreatic beta cells, not A cells.
Regarding starvation:
- A. glycogen provides enough fuel for 48 hours
- B. ketoacids derived from fats, are used by the brain and other tissues
- C. hypoglycaemia has a protein sparing effect
- D. average time until death is 40 days
Correct Answer: B
Rationale: Step-by-step rationale for the correct answer (B):
1. During starvation, the body shifts to using ketoacids derived from fats for fuel.
2. The brain and other tissues can utilize these ketoacids.
3. This process helps to spare protein and prevent muscle breakdown.
4. Therefore, choice B is correct as ketoacids play a crucial role in providing energy during starvation.
Summary of why other choices are incorrect:
A: Glycogen stores are depleted within 24 hours, not 48 hours.
C: Hypoglycemia during starvation does not have a protein sparing effect.
D: The average time until death from starvation is typically much shorter than 40 days.
Which of the following is NOT true of glucagon?
- A. produced by the pancreas
- B. increases blood glucose levels
- C. promotes the use of fat and protein instead of glucose
- D. stimulates the liver to store glucose as glycogen
Correct Answer: D
Rationale: The correct answer is D because glucagon actually stimulates the liver to release glucose into the bloodstream, not store glucose as glycogen. Glucagon helps increase blood glucose levels by promoting the breakdown of glycogen into glucose, and it also promotes the use of fat and protein for energy when glucose levels are low. Choices A, B, and C are all true statements about glucagon, making them incorrect options in this context.
Which of the following agents might mask the hypoglycemic reaction in treated diabetic patients?
- A. Beta-adrenergic agonists
- B. Alpha-adrenergic antagonists
- C. Alpha-adrenergic agonists
- D. Beta-adrenergic antagonists
Correct Answer: D
Rationale: The correct answer is D: Beta-adrenergic antagonists. Beta-blockers can mask the typical signs and symptoms of hypoglycemia such as tremors, palpitations, and sweating by inhibiting the adrenergic response to low blood sugar levels. Other choices (A, B, C) are incorrect as they do not have the same mechanism of action in masking hypoglycemic reactions in diabetic patients.