Nokea
Which of the following is descriptive of prolactin?
- A. Secreted by the posterior pituitary gland.
- B. Also called lactogenic hormone.
- C. Causes the milk let-down reflex.
- D. Stimulates the neurohypophysis to synthesize oxytocin.
Correct Answer: B
Rationale: Step-by-step rationale:
1. Prolactin is also called lactogenic hormone, as it promotes milk production in the mammary glands.
2. Secreted by the anterior pituitary gland, not the posterior pituitary gland.
3. Milk let-down reflex is primarily controlled by oxytocin, not prolactin.
4. Prolactin does not stimulate the neurohypophysis (posterior pituitary) to synthesize oxytocin.
Summary:
Choice B is correct because it accurately describes the function of prolactin in promoting lactation. Choices A, C, and D are incorrect due to inaccuracies in the functions and secretion of prolactin.
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Hypothyroidism in adults due to an underactive thyroid is ____.
- A. Graves disease.
- B. diabetes insipidus.
- C. myxedema
- D. acromegaly.
Correct Answer: C
Rationale: The correct answer is C: myxedema. Hypothyroidism in adults is commonly caused by an underactive thyroid gland, leading to decreased production of thyroid hormones. Myxedema is the term used to describe severe hypothyroidism, characterized by symptoms such as fatigue, weight gain, cold intolerance, and swelling of the face and hands. Graves disease (choice A) is actually a cause of hyperthyroidism, not hypothyroidism. Diabetes insipidus (choice B) is a disorder related to the kidneys and has no direct connection to thyroid function. Acromegaly (choice D) is caused by excess growth hormone production, unrelated to thyroid function. Therefore, the correct choice is C as it accurately describes hypothyroidism in adults.
Which of the following drugs has muscarinic and nicotinic actions and is resistant to hydrolysis by both true and pseudo cholinesterase:
- A. Acetylcholine
- B. Carbachol
- C. Bethanechol
- D. Succinylcholine
Correct Answer: B
Rationale: Step-by-step rationale for why B (Carbachol) is the correct answer:
1. Carbachol is a cholinergic drug that acts on both muscarinic and nicotinic receptors.
2. It is resistant to hydrolysis by both true and pseudo cholinesterase enzymes.
3. Acetylcholine (A) is rapidly hydrolyzed by both cholinesterases.
4. Bethanechol (C) is a muscarinic agonist but not a nicotinic agonist.
5. Succinylcholine (D) is a depolarizing neuromuscular blocking agent, not a cholinergic agonist.
Summary:
Carbachol is the only drug among the choices that has both muscarinic and nicotinic actions and is resistant to hydrolysis by cholinesterases. Acetylcholine is rapidly hydrolyzed, Bethanechol does not have nicotinic actions, and Succinyl
If farmers exposed to 'insecticides' ('irreversible' cholinesterase inhibitors) are given medical kits that contain atropine. Which one of the following effects of the cholinesterase inhibitor will NOT be blocked by the atropine?
- A. Bronchoconstriction / bronchospasm
- B. Increased bladder/urinary tract activity
- C. Increased bowel motility (i.e., diarrhea)
- D. Skeletal muscle overstimulation, eventually leading to skeletal muscle paralysis
Correct Answer: D
Rationale: The correct answer is D. Atropine blocks the effects of cholinesterase inhibitors on muscarinic receptors but not on nicotinic receptors, which are responsible for skeletal muscle overstimulation. Atropine can block bronchoconstriction, increased bladder activity, and increased bowel motility as they are mediated by muscarinic receptors. Therefore, the effects on skeletal muscle overstimulation, leading to paralysis, will not be blocked by atropine.
Which is NOT a high energy compound?
- A. CoA
- B. GGP
- C. ITP
- D. creatine phosphate
Correct Answer: B
Rationale: Correct Answer: B (GGP)
Rationale:
1. CoA, ITP, and creatine phosphate are high-energy compounds involved in various metabolic processes.
2. GGP (guanosine-5'-triphosphate) is primarily a signaling molecule, not a high-energy compound.
3. CoA is involved in acetyl group transfer, ITP in energy transfer, and creatine phosphate in ATP regeneration.
4. GGP is a nucleotide involved in signaling pathways but does not directly participate in energy transfer reactions.
Summary:
- CoA, ITP, and creatine phosphate are high-energy compounds involved in energy transfer.
- GGP is a signaling molecule and not classified as a high-energy compound.
Which organ does not have hormone production?
- A. heart
- B. kidney
- C. liver
- D. skin
Correct Answer: C
Rationale: The correct answer is C: liver. The liver does not produce hormones. Hormones are primarily produced by endocrine glands such as the pituitary, thyroid, adrenal glands, etc. The liver's main functions are related to metabolism, detoxification, and storage, rather than hormone production. The heart (choice A) produces hormones like atrial natriuretic peptide. The kidney (choice B) produces hormones like erythropoietin and renin. The skin (choice D) produces hormones like vitamin D when exposed to sunlight. Therefore, the liver is the only organ in the list that does not have hormone production.