Nokea
Virtually all of the protein or amino acid-based hormones exert their effects through intracellular ________.
- A. ions
- B. deactivators
- C. nucleotides
- D. second messengers
Correct Answer: D
Rationale: The correct answer is D: second messengers. Protein or amino acid-based hormones are unable to pass through the cell membrane due to their large size and hydrophilic nature. Therefore, they bind to specific receptors on the cell surface, triggering a series of events that lead to the production of second messengers inside the cell. These second messengers, such as cyclic AMP or calcium ions, then transmit the hormonal signal to the target cell's interior to initiate a physiological response. Choices A, B, and C are incorrect because protein or amino acid-based hormones do not directly exert their effects through ions, deactivators, or nucleotides intracellularly.
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Ketoacidosis is most related to:
- A. adrenocortical insufficiency.
- B. Cushing syndrome.
- C. excess fatty acid catabolism.
- D. hyperglycemia.
Correct Answer: C
Rationale: Ketoacidosis is most related to excess fatty acid catabolism. During this process, the body breaks down fatty acids into ketones, leading to an accumulation of ketones in the blood and causing metabolic acidosis. Adrenocortical insufficiency (A) is related to cortisol deficiency, not ketoacidosis. Cushing syndrome (B) is associated with excess cortisol production, not ketoacidosis. Hyperglycemia (D) is high blood sugar levels and is not directly related to the mechanism of ketoacidosis.
Which is NOT produced by the citric acid cycle?
- A. NAD+
- B. CO2
- C. GTP
- D. FADH2
Correct Answer: A
Rationale: Step 1: NAD+ is a reactant in the citric acid cycle, not a product.
Step 2: NAD+ is reduced to NADH during the cycle.
Step 3: NAD+ is not directly produced as a final product in the cycle.
Step 4: Therefore, A: NAD+ is NOT produced by the citric acid cycle.
Summary: B: CO2 and D: FADH2 are produced in the cycle, while C: GTP is generated through substrate-level phosphorylation.
Which of the following is NOT true of Cushing syndrome?
- A. trunk (torso) becomes obese
- B. basic blood pH
- C. moon-shaped face
- D. hyposecretion of adrenal cortex hormones.
Correct Answer: D
Rationale: Step-by-step rationale:
1. Cushing syndrome is characterized by hypersecretion of adrenal cortex hormones, not hyposecretion.
2. Option D states hyposecretion, which is incorrect for Cushing syndrome.
3. Trunk obesity, moon-shaped face, and alkalosis (basic blood pH) are characteristic features of Cushing syndrome.
4. Thus, option D is the correct answer because it is not a true characteristic of Cushing syndrome.
Summary:
Option D is incorrect because Cushing syndrome is associated with hypersecretion of adrenal cortex hormones, not hyposecretion. Options A, B, and C are true characteristics of Cushing syndrome, making them incorrect choices.
Each of the following parasympathomimetic drugs is correctly matched with an appropriate pharmacological action EXCEPT:
- A. Methacholine - vasodilation of peripheral blood vessels
- B. Neostigmine - stimulation of skeletal muscles
- C. Pilocarpine - increased sweat secretion
- D. Bethanechol - increased intraocular pressure
Correct Answer: D
Rationale: The correct answer is D. Bethanechol is a parasympathomimetic drug that primarily acts on muscarinic receptors in the bladder and gastrointestinal tract, causing increased smooth muscle contraction and promoting urination and improved GI motility. It does not affect intraocular pressure.
A, B, and C are incorrect:
A: Methacholine - acts as a muscarinic agonist causing bronchoconstriction, not vasodilation.
B: Neostigmine - inhibits acetylcholinesterase leading to increased acetylcholine levels, enhancing neuromuscular transmission, not directly stimulating skeletal muscles.
C: Pilocarpine - acts on muscarinic receptors in the eye, causing miosis and increased aqueous humor outflow, not increased sweat secretion.
The neurohypophysis or posterior lobe of the pituitary gland is not a true endocrine gland because ________.
- A. it is strictly a part of the neural system and has little or nothing to do with hormonal release
- B. embryonically it was an endocrine tissue, but in the adult human it is no longer functional
- C. it is unable to function as an endocrine tissue because it is actually part of the neural system due to its location
- D. it is only a hormone storage area that receives hormones from the hypothalamus for release
Correct Answer: D
Rationale: The correct answer is D because the neurohypophysis stores hormones produced by the hypothalamus for release into the bloodstream. The neurohypophysis does not produce its own hormones but acts as a storage and release site.
A is incorrect as the neurohypophysis does play a role in hormonal release through the release of hormones produced by the hypothalamus. B is incorrect as the neurohypophysis remains functional in adults. C is incorrect as the neurohypophysis does function as an endocrine tissue by releasing hormones into the bloodstream.