Nokea
The endocrine gland(s) referred to as the 'master gland' is the:
- A. pancreas
- B. adrenal glands
- C. thyroid gland
- D. pituitary gland
Correct Answer: D
Rationale: The correct answer is D: pituitary gland. The pituitary gland is often referred to as the 'master gland' because it controls the functions of other endocrine glands in the body. It secretes hormones that regulate various bodily functions such as growth, metabolism, and reproduction. It is located at the base of the brain and is divided into two parts: anterior and posterior. The anterior pituitary gland produces and releases several important hormones that influence other endocrine glands. The other choices (A: pancreas, B: adrenal glands, C: thyroid gland) do not have the same broad regulatory control over the endocrine system as the pituitary gland.
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The major targets of growth hormone are ________.
- A. the blood vessels
- B. the adrenal glands
- C. the liver
- D. bones and skeletal muscles
Correct Answer: D
Rationale: The correct answer is D: bones and skeletal muscles. Growth hormone primarily targets these tissues to promote growth and development. Growth hormone stimulates bone growth by acting on bone cells and increasing protein synthesis in skeletal muscles, leading to muscle growth. The other choices are incorrect because growth hormone does not directly target blood vessels, adrenal glands, or the liver for growth-promoting effects. Growth hormone primarily affects bone and muscle tissues for growth and repair.
A patient presents with a tumor of the adrenal gland. It is determined that the levels of renin-angiotensin is low. Which of the following would lead to increased renin-angiotensin levels?
- A. Cushing's syndrome
- B. Secondary hyperaldosteronism
- C. Primary hyperaldosteronism, Conn's syndrome
- D. A and B
Correct Answer: B
Rationale: The correct answer is B: Secondary hyperaldosteronism. In this scenario, the low renin-angiotensin levels indicate a feedback mechanism where the body is trying to compensate for high aldosterone levels. Secondary hyperaldosteronism, which can be caused by conditions like renal artery stenosis or heart failure, leads to increased aldosterone secretion independent of renin levels, resulting in low renin-angiotensin levels.
A: Cushing's syndrome is associated with excess cortisol production, but it does not directly influence renin-angiotensin levels.
C: Primary hyperaldosteronism (Conn's syndrome) is characterized by high aldosterone levels, not low renin-angiotensin levels.
D: Both Cushing's syndrome and secondary hyperaldosteronism do not necessarily occur together, making this option incorrect.
What is the most likely effect of a deficiency of aldosterone?
- A. High blood pressure
- B. Low level of potassium in the blood
- C. Low blood volume and hypotension
- D. Goiter formation
Correct Answer: C
Rationale: Rationale:
1. Aldosterone regulates sodium and water balance in the body.
2. Deficiency leads to decreased sodium reabsorption, causing low blood volume.
3. Low blood volume results in hypotension due to reduced blood flow to tissues.
4. Choices A and B are incorrect as aldosterone deficiency does not cause high blood pressure or low potassium levels.
5. Choice D is incorrect as goiter formation is mainly related to thyroid hormone imbalance, not aldosterone deficiency.
Melatonin from the pineal gland regulates ____.
- A. sleep-wake cycles.
- B. water balance.
- C. sexual development.
- D. Both A and C
Correct Answer: D
Rationale: The correct answer is D, Both A and C. Melatonin from the pineal gland regulates sleep-wake cycles (A) by influencing the body's internal clock. It also plays a role in sexual development (C) by influencing the release of reproductive hormones. Other choices, B (water balance), are regulated by hormones like ADH and aldosterone, not melatonin. The correct answer encompasses the functions of melatonin in both sleep regulation and sexual development.
Organophosphate insecticides and nerve gases exert their lethal effects by:
- A. Blocking alpha and β-adrenergic receptors
- B. Blocking all muscarinic receptors on target cells
- C. Blocking nicotinic receptors in the brain
- D. Inhibiting acetylcholine metabolism
Correct Answer: D
Rationale: The correct answer is D because organophosphate insecticides and nerve gases inhibit acetylcholine metabolism by irreversibly binding to acetylcholinesterase enzyme, leading to accumulation of acetylcholine at synapses. This results in overstimulation of cholinergic receptors, causing symptoms of cholinergic toxicity.
Choice A is incorrect because alpha and beta-adrenergic receptors are not the targets of organophosphates. Choice B is incorrect because organophosphates do not block all muscarinic receptors. Choice C is incorrect because organophosphates do not specifically target nicotinic receptors in the brain.