Nokea
Which of the following is not controlled by a hypothalamic-releasing hormone?
- A. ACTH
- B. ADH
- C. Growth hormone
- D. Prolactin
Correct Answer: B
Rationale: The correct answer is B: ADH. Hypothalamic-releasing hormones regulate anterior pituitary hormones. ADH is produced in the hypothalamus but stored and released by the posterior pituitary, not controlled by a hypothalamic-releasing hormone. ACTH, growth hormone, and prolactin are all controlled by hypothalamic-releasing hormones such as CRH, GHRH, and PRH, respectively.
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Which of the following systems work closely with the endocrine system to coordinate the body's functions?
- A. Cardiovascular system
- B. Respiratory system
- C. Reproductive system
- D. Nervous system
Correct Answer: D
Rationale: The correct answer is D: Nervous system. The nervous system works closely with the endocrine system to regulate and coordinate the body's functions through the release of neurotransmitters and hormones. The nervous system controls rapid responses, while the endocrine system controls slower, long-term processes. The cardiovascular system (A) primarily transports blood and nutrients, the respiratory system (B) is involved in gas exchange, and the reproductive system (C) is responsible for reproduction, none of which directly coordinate with the endocrine system.
Most of the endocrine system is regulated by:
- 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 are essential in regulating hormone levels within a narrow range to maintain homeostasis. When hormone levels rise, negative feedback mechanisms signal the body to decrease production, and vice versa. Positive feedback mechanisms amplify hormone production, not regulate it. Hormone-receptor complexes and hormone-gene complexes are important for hormone actions but do not regulate the overall endocrine system.
Most endocrine secretions are controlled by _____.
- A. positive feedback.
- B. negative feedback.
- C. neural feedback.
Correct Answer: B
Rationale: Step 1: Negative feedback is the primary mechanism in endocrine system regulation to maintain homeostasis.
Step 2: When hormone levels reach a certain set point, negative feedback signals the gland to stop producing that hormone.
Step 3: This ensures that hormone levels remain within a specific range.
Step 4: Positive feedback would lead to further hormone secretion, disrupting homeostasis.
Step 5: Neural feedback is not a common mechanism for regulating endocrine secretions.
Which is NOT an action of CCK?
- A. gallbladder contraction
- B. increased gastric motility and emptying
- C. glucagon secretion
- D. secretion of pancreatic juice
Correct Answer: B
Rationale: The correct answer is B: increased gastric motility and emptying. CCK, or cholecystokinin, is a hormone released by the small intestine in response to the presence of fats. Its main actions include stimulating gallbladder contraction (A) to release bile for fat digestion, triggering the secretion of pancreatic juice (D) containing digestive enzymes, and inhibiting gastric motility and emptying. Therefore, increased gastric motility and emptying (choice B) is NOT an action of CCK. This is because CCK acts to slow down gastric emptying to allow for effective digestion of fats in the small intestine. Choices A, C, and D are all correct actions of CCK based on its role in the digestive process.
Adrenaline can be used in the following EXCEPT:
- A. Allergic reactions
- B. Acute bronchial asthma
- C. Complete heart block
- D. Angina pectoris
Correct Answer: D
Rationale: Adrenaline is a sympathomimetic drug that acts on adrenergic receptors. In acute situations like allergic reactions, bronchial asthma, and heart block, adrenaline can be beneficial due to its bronchodilator and vasoconstrictor effects. However, in angina pectoris, which is caused by reduced blood flow to the heart muscle, the vasoconstrictor effect of adrenaline can worsen the condition by increasing the workload of the heart. Therefore, adrenaline should not be used in angina pectoris.