Nokea
A patient with Alzheimer's disease is taking an acetylcholinesterase inhibitor specifically approved for that indication, primarily because it is quite lipophilic and so enters the CNS well. Which of the following drugs is the patient most likely receiving?
- A. Donepezil
- B. Edrophonium
- C. Neostigmine
- D. Pyridostigmine
Correct Answer: A
Rationale: The correct answer is A: Donepezil. Donepezil is a lipophilic acetylcholinesterase inhibitor approved for Alzheimer's disease due to its ability to enter the CNS effectively. It enhances cholinergic transmission by inhibiting the enzyme responsible for acetylcholine breakdown. Edrophonium is a short-acting acetylcholinesterase inhibitor used for diagnostic purposes, not for Alzheimer's treatment. Neostigmine and Pyridostigmine are not lipophilic and are primarily used for myasthenia gravis to enhance muscle strength, not for Alzheimer's disease.
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Which of the following hormones are responsible for the 'fight-or-flight' response?
- A. Epinephrine and norepinephrine.
- B. Insulin and glucagon.
- C. Esrtogen and progesterone.
- D. Thyroxin and melatonin.
Correct Answer: A
Rationale: The correct answer is A: Epinephrine and norepinephrine. These hormones are released by the adrenal glands during stressful situations to trigger the 'fight-or-flight' response. They increase heart rate, blood pressure, and energy production to prepare the body for action. Insulin and glucagon (B) regulate blood sugar levels. Estrogen and progesterone (C) are female sex hormones. Thyroxin and melatonin (D) are involved in metabolism and sleep regulation, respectively. Therefore, only A directly relates to the physiological response of 'fight-or-flight'.
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
Identify the growth factor that is released by cancer cells to create a capillary network that aids the cancer growth.
- A. macrophage colony-stimulating factor
- B. platelet derived growth factor
- C. tumor angiogenesis factor
- D. epidermal growth factor
Correct Answer: C
Rationale: The correct answer is C, tumor angiogenesis factor. Cancer cells release this growth factor to promote the formation of new blood vessels (angiogenesis) around the tumor, providing a supply of nutrients and oxygen to support their growth. This process is essential for cancer progression.
A: Macrophage colony-stimulating factor is involved in the production and differentiation of macrophages, not in angiogenesis.
B: Platelet-derived growth factor promotes cell growth and division, but it is not specifically responsible for angiogenesis in the context of cancer.
D: Epidermal growth factor is a signaling molecule that promotes cell proliferation and differentiation but is not the primary factor released by cancer cells to induce angiogenesis.
Which sentences are correct?
- A. 1 only
- B. 1 and 2 only
- C. 1, 2 and 3
- D. 2 and 3 only
Correct Answer: B
Rationale: The correct answer is B: 1 and 2 only. Sentence 1 and 2 are correct because they are grammatically accurate and logically coherent. Sentence 3 is incorrect as it contains a grammatical error. The key is to analyze each sentence independently to determine its correctness based on grammar, clarity, and logical consistency. In this case, only sentences 1 and 2 meet the criteria, making B the correct choice.
Hypersecretion of antidiuretic hormone (ADH) can occur in all of the following situations EXCEPT __________.
- A. damage to the pineal gland
- B. after neurosurgery
- C. after general anesthesia
- D. ectopic ADH secretion by pulmonary cancer
Correct Answer: A
Rationale: The correct answer is A: damage to the pineal gland. The pineal gland does not regulate ADH secretion; it primarily produces melatonin. Neurosurgery and general anesthesia may disrupt the feedback mechanisms controlling ADH release. Ectopic ADH secretion by pulmonary cancer can lead to excessive ADH production. The key is to identify a situation where ADH hypersecretion is less likely to occur due to the gland's function.