Nokea
α-1 adrenergic receptors are selectively blocked by:
- A. Phentolamine
- B. Prazosin
- C. Propranolol
- D. Ergotamine
Correct Answer: B
Rationale: The correct answer is B: Prazosin. α-1 adrenergic receptors are selectively blocked by prazosin. Prazosin is a selective α-1 adrenergic receptor antagonist, specifically targeting these receptors. It works by blocking the effects of norepinephrine, leading to vasodilation and reduced blood pressure.
A: Phentolamine is a non-selective α-adrenergic receptor antagonist, blocking both α-1 and α-2 receptors.
C: Propranolol is a non-selective β-adrenergic receptor antagonist, blocking β-1 and β-2 receptors.
D: Ergotamine is a medication used for the treatment of migraines and has vasoconstrictive properties but does not selectively block α-1 adrenergic receptors.
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Which of the following is NOT synthesized in the pituitary gland?
- A. LH
- B. FSH
- C. ADH
- D. TSH
Correct Answer: C
Rationale: The correct answer is C: ADH. The pituitary gland consists of two parts: the anterior and posterior pituitary. ADH, also known as vasopressin, is synthesized in the hypothalamus and stored in the posterior pituitary. Therefore, it is not synthesized in the pituitary gland itself. LH, FSH, and TSH are all hormones synthesized and released by the anterior pituitary gland.
What is the role of the adrenal gland during moments of danger?
- A. Secrete hormones that lower metabolism.
- B. Secrete hormones that speed up digestion.
- C. Secrete hormones that increase heart rate and blood pressure.
- D. Secrete hormones that decrease heart rate and blood pressure.
Correct Answer: C
Rationale: The correct answer is C because during moments of danger, the adrenal gland secretes hormones like adrenaline and cortisol to prepare the body for a "fight or flight" response. These hormones increase heart rate and blood pressure to supply more oxygen and nutrients to the muscles, enabling the body to react quickly to the danger. Choices A, B, and D are incorrect because lowering metabolism, speeding up digestion, and decreasing heart rate and blood pressure are not adaptive responses to danger.
Insulin:
- A. is secreted by the beta cells of the islets of Langerhans.
- B. is secreted by the liver.
- C. raises blood glucose levels.
- D. is released by the pancreas in response to low blood glucose levels.
Correct Answer: A
Rationale: Step-by-step rationale:
1. Insulin is a hormone that regulates blood glucose levels by promoting glucose uptake into cells.
2. Beta cells of the islets of Langerhans in the pancreas are responsible for secreting insulin.
3. Insulin lowers blood glucose levels by enhancing glucose uptake and storage.
4. Therefore, choice A is correct as it accurately identifies the source of insulin secretion.
Summary:
- Choice B is incorrect as the liver does not secrete insulin.
- Choice C is incorrect as insulin lowers blood glucose levels.
- Choice D is incorrect as insulin is released in response to high, not low, blood glucose levels.
The neurotransmitter released at the end of most sympathetic nerve fibers is:
- A. Epinephrine
- B. Noradrenaline
- C. Acetylcholine
- D. Acetylcholinesterase
Correct Answer: B
Rationale: The correct answer is B: Noradrenaline. Sympathetic nerve fibers release noradrenaline as the primary neurotransmitter to activate the fight-or-flight response. Noradrenaline acts on adrenergic receptors to increase heart rate, blood pressure, and blood flow to muscles. Epinephrine (choice A) is also released in the sympathetic nervous system but mainly by the adrenal glands. Acetylcholine (choice C) is the primary neurotransmitter in the parasympathetic nervous system. Acetylcholinesterase (choice D) is an enzyme that breaks down acetylcholine and is not a neurotransmitter.
Mr. B, diagnosed with hypothyroidism, is being discharged after starting thyroid hormone therapy. Which of the following would indicate that the treatment is effective?
- A. A decrease in weight
- B. Normal serum thyroid hormone levels
- C. Relief of fatigue
- D. Increased appetite
Correct Answer: B
Rationale: Effective treatment for hypothyroidism is indicated by normalization of thyroid hormone levels, which helps alleviate symptoms like fatigue and weight gain.