Nokea
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.
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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.
Which of the following statements about the hormone glucagon is true?
- A. It is secreted by the beta cells in the islets of Langerhans
- B. It is secreted in response to a rise in blood glucose
- C. It promotes the breakdown of glycogen in the liver
- D. It promotes the synthesis of glycogen in the liver
Correct Answer: C
Rationale: The correct answer is C: Glucagon promotes the breakdown of glycogen in the liver. Glucagon is secreted by the alpha cells in the islets of Langerhans in response to low blood glucose levels. When released, glucagon stimulates the liver to break down glycogen into glucose through a process called glycogenolysis, thus increasing blood glucose levels. This helps maintain blood glucose homeostasis during fasting or low glucose conditions. Options A and B are incorrect because glucagon is secreted by alpha cells, not beta cells, and in response to low blood glucose, not high. Option D is incorrect as glucagon promotes glycogen breakdown, not synthesis.
The action of ganglion blockers on the following items is essentially similar to atropine EXCEPT on:
- A. Eye
- B. Gastrointestinal tract
- C. Urinary bladder
- D. Blood pressure
Correct Answer: D
Rationale: The correct answer is D: Blood pressure. Ganglion blockers, similar to atropine, block the transmission of nerve impulses at ganglia. Ganglion blockers affect the eye, gastrointestinal tract, and urinary bladder by inhibiting parasympathetic activity. However, ganglion blockers do not have a significant direct effect on blood pressure regulation. Blood pressure is primarily regulated by the autonomic nervous system through the actions of the sympathetic and parasympathetic systems, not solely at ganglia. Therefore, the correct answer is D because ganglion blockers do not directly influence blood pressure regulation.
Which of the following produced only by large amounts of glucocorticoids?
- A. Normal responsiveness of fat depots to norepinephrine
- B. Maintenance of normal vascular reactivity
- C. Increased excretion of a water load
- D. Inhibition of the inflammatory response
Correct Answer: D
Rationale: The correct answer is D because glucocorticoids inhibit the inflammatory response by suppressing the immune system. Glucocorticoids reduce inflammation by blocking the production of inflammatory substances like prostaglandins and cytokines. This effect is only observed in large amounts of glucocorticoids. Choices A, B, and C are not produced exclusively by large amounts of glucocorticoids. Normal responsiveness of fat depots to norepinephrine and maintenance of normal vascular reactivity are not directly related to glucocorticoids in large amounts. Increased excretion of a water load is more influenced by other factors such as hydration status and renal function.
Which of the following is true of both prolactin and oxytocin? Both
- A. are concerned with lactation.
- B. are secreted by the adenohypophysis.
- C. stimulate the mammary glands to make milk.
- D. are concerned only with lactation.
Correct Answer: A
Rationale: The correct answer is A: are concerned with lactation. Both prolactin and oxytocin are hormones involved in lactation. Prolactin promotes milk production in the mammary glands, while oxytocin stimulates the release of milk from the breasts during breastfeeding. Therefore, both hormones play crucial roles in the lactation process.
Choice B is incorrect because oxytocin is secreted by the posterior pituitary gland, not the adenohypophysis. Choice C is incorrect because oxytocin specifically stimulates the contraction of the muscles around the mammary glands to release milk, not the production of milk. Choice D is incorrect because oxytocin is also involved in milk ejection, not just lactation itself.