Which of the following are incorrectly paired?
- A. Gluconeogenesis : Cortisol
- B. Free fatty acid mobilization : Dehydroepiandrosterone
- C. Muscle glycogenolysis : Epinephrine
- D. Kaliuresis : Aldosterone
Correct Answer: B
Rationale: The correct answer is B because free fatty acid mobilization is primarily regulated by cortisol, not dehydroepiandrosterone. Cortisol promotes lipolysis and stimulates the release of free fatty acids from adipose tissue. Dehydroepiandrosterone is a precursor hormone mainly involved in sex hormone production and has minimal effects on free fatty acid mobilization. Choices A, C, and D are correctly paired as gluconeogenesis is stimulated by cortisol, muscle glycogenolysis is regulated by epinephrine, and kaliuresis is induced by aldosterone.
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Antidiuretic hormone _______________.
- A. controls metabolic rate
- B. controls the amount of urine one produces
- C. increases blood sugar
- D. controls reproduction
Correct Answer: B
Rationale: The correct answer is B: controls the amount of urine one produces. Antidiuretic hormone (ADH) acts on the kidneys to regulate water reabsorption, thereby controlling the amount of urine produced. It does not control metabolic rate (A), increase blood sugar (C), or control reproduction (D). ADH's main function is to maintain water balance in the body by reducing urine output.
ACTH, TSH, and gonadotropins are:
- A. hypothalamic-releasing hormones.
- B. secreted by the neurohypophysis.
- C. “aimed at†the adrenal cortex.
- D. tropic hormones.
Correct Answer: D
Rationale: Step 1: ACTH, TSH, and gonadotropins are hormones that stimulate the secretion of other hormones.
Step 2: These hormones target specific endocrine glands, such as the adrenal cortex.
Step 3: Since these hormones stimulate the secretion of other hormones and target specific glands, they are classified as tropic hormones.
Step 4: Thus, the correct answer is D: tropic hormones.
Summary: A is incorrect as they are not hypothalamic-releasing hormones. B is incorrect as they are not secreted by the neurohypophysis. C is incorrect as they are not specifically aimed at the adrenal cortex.
Which of the following is NOT a symptom of Addison’s disease?
- A. Salt craving
- B. Weight gain
- C. Hypoglycemia
- D. Hyperpigmentation
Correct Answer: B
Rationale: The correct answer is B: Weight gain. Addison's disease is characterized by adrenal insufficiency, leading to symptoms such as salt craving, hypoglycemia, and hyperpigmentation due to increased melanin production. Weight loss, not weight gain, is commonly associated with Addison's disease due to decreased cortisol levels. Salt craving is due to sodium loss, hypoglycemia results from insufficient cortisol levels, and hyperpigmentation is caused by elevated ACTH levels stimulating melanin production. Weight gain is not a typical symptom, making it the correct answer.
When an action potential reaches the axon terminal, what happens next?
- A. The muscle fiber contracts
- B. Acetylcholinesterase breaks down acetylcholine in the synaptic cleft
- C. Endosomes containing neurotransmitter fuse to cell membrane, and release neurotransmitter into the synaptic cleft
- D. Sodium channels open at the motor end plate, moving the cell membrane closer to threshold
Correct Answer: c
Rationale: The correct answer is C because when an action potential reaches the axon terminal, endosomes containing neurotransmitters fuse with the cell membrane and release neurotransmitter into the synaptic cleft. This process is known as exocytosis. This neurotransmitter then binds to receptors on the postsynaptic neuron, initiating a new action potential.
Choice A is incorrect because the muscle fiber contraction is initiated by the binding of the neurotransmitter to receptors on the muscle cell, not directly by the action potential reaching the axon terminal.
Choice B is incorrect because acetylcholinesterase breaks down acetylcholine in the synaptic cleft after it has already been released and has completed its role in transmitting the signal.
Choice D is incorrect because sodium channels opening at the motor end plate is part of the process of muscle cell depolarization and contraction, not directly related to the release of neurotransmitter at the axon terminal.
Which of the following statements about anticholinesterase drugs is WRONG:
- A. They can be divided into reversible and irreversible types
- B. They include neostigmine and physostigmine
- C. They can produce miosis and lacrimation
- D. They are useful bronchodilators
Correct Answer: D
Rationale: The correct answer is D because anticholinesterase drugs are not bronchodilators; they actually increase cholinergic activity by inhibiting the breakdown of acetylcholine. Reversible and irreversible types do exist (A), neostigmine and physostigmine are examples (B), and they can cause miosis and lacrimation due to increased cholinergic activity (C). Hence, D is the incorrect statement.