Nokea
Eicosanoids are not true hormones because they __________.
- A. they act locally, not on distal organs as do true hormones
- B. don't have target organs
- C. mediate inflammatory reactions
- D. are lipid in nature
Correct Answer: A
Rationale: The correct answer is A. Eicosanoids are not true hormones because they act locally, not on distal organs like true hormones. Eicosanoids are produced and released in response to specific stimuli at the site of action, affecting nearby cells. This local action distinguishes them from true hormones, which are produced in one part of the body and travel through the bloodstream to distant target organs to elicit a response. Choices B, C, and D are incorrect because eicosanoids do have target organs (B), mediate inflammatory reactions (C), and are lipid in nature (D), but these characteristics do not define them as hormones.
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Which mechanism is primarily responsible for maintaining hormone levels within a narrow range?
- A. negative feedback mechanisms
- B. positive feedback mechanisms
- C. hormone-receptor complexes
- D. hormone-gene complexes
Correct Answer: A
Rationale: The correct answer is A: negative feedback mechanisms. Negative feedback mechanisms help maintain hormone levels within a narrow range by inhibiting further hormone production once a certain level is reached. When hormone levels rise, negative feedback signals the body to decrease hormone production, preventing excessive levels. Positive feedback mechanisms, on the other hand, amplify hormone production. Hormone-receptor complexes and hormone-gene complexes are not directly responsible for maintaining hormone levels within a narrow range but rather play roles in hormone signaling and gene expression, respectively.
Which statements about air pollutants are correct?
- A. 1 and 2
- B. 1 and 3
- C. 2 and 4
- D. 3 and 4
Correct Answer: D
Rationale: Certainly! The correct answer is D because it includes statements 3 and 4, which are both true. Statement 3 is correct, as air pollutants can lead to various health issues. Statement 4 is also accurate, as air pollutants can contribute to environmental degradation. Statements 1 and 2 are incorrect as they are not included in the correct answer. Statement 1 may not be universally applicable, and statement 2 does not cover the broad impact of air pollutants on both health and the environment as indicated in statements 3 and 4. Therefore, choice D is the most accurate based on the information provided.
Nervousness, increased body temperature, and increased blood-pressure are indications of _______.
- A. diabetes mellitus
- B. hypoglycemia
- C. hypothyroidism
- D. hyperthyroidism
Correct Answer: D
Rationale: The correct answer is D: hyperthyroidism. Nervousness, increased body temperature, and increased blood pressure are classic symptoms of hyperthyroidism. This condition is characterized by an overactive thyroid gland, leading to an excess production of thyroid hormones. These hormones can cause an increase in metabolism, leading to symptoms such as nervousness, heat intolerance, and elevated heart rate. Diabetes mellitus (A) is not associated with increased body temperature or blood pressure. Hypoglycemia (B) is characterized by low blood sugar levels, leading to symptoms such as dizziness and confusion, not increased body temperature. Hypothyroidism (C) is characterized by an underactive thyroid gland, leading to symptoms such as fatigue, weight gain, and cold intolerance, not increased body temperature or blood pressure.
Which of the following hormones does the skin produce?
- A. erythropoietin
- B. melatonin
- C. renin
- D. cholecalciferol
Correct Answer: D
Rationale: The correct answer is D: cholecalciferol. The skin produces cholecalciferol, also known as vitamin D, in response to sunlight exposure. This hormone plays a crucial role in calcium absorption and bone health. Erythropoietin (A) is produced by the kidneys to stimulate red blood cell production. Melatonin (B) is produced by the pineal gland to regulate sleep-wake cycles. Renin (C) is produced by the kidneys to regulate blood pressure. Therefore, the skin does not produce erythropoietin, melatonin, or renin, making them incorrect choices.
With regard to carbohydrate digestion:
- A. salivary amylase works best at alkaline pH
- B. approximately 40% of adult Europeans are lactose intolerant
- C. oligosaccharidase deficiency results in osmotic diarrhoea
- D. salivary amylase continues to digest carbohydrates in the stomach
Correct Answer: C
Rationale: Step-by-step rationale for choice C being correct:
1. Oligosaccharidase deficiency impairs breakdown of oligosaccharides in the small intestine.
2. Undigested oligosaccharides draw water into the intestines, causing osmotic diarrhea.
3. This leads to increased fluid content in the stool, resulting in osmotic diarrhea.
4. This process does not involve salivary amylase or lactose intolerance.