Nokea
X is a drug that contains a mixture of amphetamines. It is used for managing Attention-Deficit/Hyperactivity disorder (ADHD). The drug causes autonomic effects that can be fatal if an overdose is taken. How does X work in the body?
- A. Blocks muscarinic receptors, causing what is basically 'atropine poisoning'
- B. Blocks β2 receptors on airway smooth muscle, causing bronchoconstriction
- C. Inhibits MAO, leading to a 'shut-down' of the sympathetic nervous system
- D. Releases neuronal noradrenaline, causing excessive sympathetic effects, e.g., severe rises of blood pressure
Correct Answer: D
Rationale: The correct answer is D because X, a mixture of amphetamines, works by releasing neuronal noradrenaline, causing excessive sympathetic effects like severe rises in blood pressure. This is how the drug helps manage ADHD symptoms. The other choices are incorrect because A (blocking muscarinic receptors) would not be related to the autonomic effects seen with X, B (blocking β2 receptors) would not explain the fatal autonomic effects, and C (inhibiting MAO) would not lead to the described autonomic effects. Therefore, D is the correct choice based on how X works in the body to produce its effects on the sympathetic nervous system.
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The secretion of cortisol by the adrenal gland suppresses further secretion of ACTH by the anterior pituitary gland. What is this interaction called?
- A. Cerebral lateralization
- B. Circadian rhythm
- C. Cellular differentiation
- D. Negative feedback control
Correct Answer: D
Rationale: The correct answer is D: Negative feedback control. This interaction is a classic example of negative feedback control in the endocrine system. Cortisol inhibits the release of ACTH, which in turn reduces the stimulation of cortisol production, creating a feedback loop to maintain hormonal balance. Choice A, cerebral lateralization, refers to the specialization of brain function. Choice B, circadian rhythm, pertains to the 24-hour biological cycle. Choice C, cellular differentiation, involves the process of cells becoming specialized for specific functions. Thus, the correct answer is D because it accurately describes the feedback mechanism at play in the cortisol-ACTH interaction.
The primary target of the releasing and inhibiting hormones of the hypothalamus is the:
- A. Liver and adipose tissue
- B. Gonads
- C. Anterior pituitary
- D. Bone marrow
Correct Answer: C
Rationale: The correct answer is C. The primary target of releasing and inhibiting hormones from the hypothalamus is the anterior pituitary. The hypothalamus secretes these hormones into the hypophyseal portal system, which directly connects to the anterior pituitary. This interaction controls the release of various hormones from the anterior pituitary, regulating functions such as growth, reproduction, and stress response. Choices A, B, and D are incorrect because releasing and inhibiting hormones from the hypothalamus do not primarily target the liver, adipose tissue, gonads, or bone marrow directly.
The following statements concerning prazosin and phentolamine are correct EXCEPT:
- A. Both antagonize alpha1-receptors
- B. Both cause the same degree of tachycardia
- C. Both decrease blood pressure
- D. Both are competitive antagonists
Correct Answer: B
Rationale: Correct Answer: B
Rationale:
1. Prazosin and phentolamine both antagonize alpha1-receptors, leading to vasodilation and decreased blood pressure.
2. Both drugs are competitive antagonists, competing with norepinephrine at alpha1-receptors.
3. However, phentolamine causes reflex tachycardia due to its non-selective alpha-adrenergic blockade, unlike prazosin.
4. Therefore, the statement that both cause the same degree of tachycardia is incorrect based on their pharmacological differences.
What manifestations of endocrine problems in the older adult are commonly attributed to the aging process?
- A. Tremors and paresthesias
- B. Fatigue and mental impairment
- C. Hyperpigmentation and oily skin
- D. Fluid retention and hypertension
Correct Answer: B
Rationale: Fatigue and mental impairment are often attributed to normal aging but may indicate an underlying endocrine disorder such as hypothyroidism or adrenal insufficiency.
Growth hormone:
- A. is secreted by the adenohypophysis.
- B. stimulates growth of the musculoskeletal system.
- C. is also called somatotropic hormone.
- D. all is applicable.
Correct Answer: D
Rationale: Certainly! The correct answer is D because growth hormone is indeed secreted by the adenohypophysis, it stimulates growth of the musculoskeletal system, and it is also known as somatotropic hormone. All the statements in choices A, B, and C are true regarding growth hormone, making option D the correct choice. The other choices are incorrect because they do not encompass all the functions and characteristics of growth hormone as described in the question.