Which of the following is NOT related to adrenal medulla structure and function?
- A. Inner portion of adrenal gland.
- B. Controlled by the nervous system.
- C. Regulates levels of glucose and minerals in the blood.
- D. Produces epinephrine and norepinephrine.
Correct Answer: C
Rationale: The correct answer is C: Regulates levels of glucose and minerals in the blood. The adrenal medulla is responsible for producing epinephrine and norepinephrine, not regulating blood glucose and minerals. The inner portion of the adrenal gland refers to the adrenal medulla. It is controlled by the nervous system, specifically the sympathetic nervous system. Epinephrine and norepinephrine produced by the adrenal medulla are involved in the body's fight-or-flight response, not in regulating blood glucose and minerals. Therefore, choice C is the correct answer as it is not related to adrenal medulla structure and function.
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A common second messenger used in signaling pathways of water-soluble hormones is
- A. tRNA.
- B. ATP.
- C. cAMP.
- D. PTH.
Correct Answer: C
Rationale: The correct answer is C: cAMP. Water-soluble hormones, such as adrenaline or glucagon, bind to cell surface receptors and activate a signaling cascade that often involves cAMP as a second messenger. Upon hormone binding, the receptor activates adenylyl cyclase, which converts ATP to cAMP. cAMP then activates protein kinase A, leading to phosphorylation of target proteins, ultimately affecting cellular responses.
Explanation for incorrect choices:
A: tRNA is involved in protein synthesis, not in signaling pathways of water-soluble hormones.
B: ATP is used as an energy source in various cellular processes, but it is not a second messenger in hormone signaling pathways.
D: PTH (parathyroid hormone) is a hormone involved in calcium regulation and does not act through cAMP signaling in the same manner as water-soluble hormones.
Regarding starvation:
- A. glycogen provides enough fuel for 48 hours
- B. ketoacids derived from fats, are used by the brain and other tissues
- C. hypoglycaemia has a protein sparing effect
- D. average time until death is 40 days
Correct Answer: B
Rationale: Step-by-step rationale for the correct answer (B):
1. During starvation, the body shifts to using ketoacids derived from fats for fuel.
2. The brain and other tissues can utilize these ketoacids.
3. This process helps to spare protein and prevent muscle breakdown.
4. Therefore, choice B is correct as ketoacids play a crucial role in providing energy during starvation.
Summary of why other choices are incorrect:
A: Glycogen stores are depleted within 24 hours, not 48 hours.
C: Hypoglycemia during starvation does not have a protein sparing effect.
D: The average time until death from starvation is typically much shorter than 40 days.
Which of these is not an endocrine gland?
- A. Pancreas.
- B. Testes.
- C. Salivary gland.
- D. Parathyroid.
Correct Answer: C
Rationale: The correct answer is C, the salivary gland. The salivary gland is not an endocrine gland because it secretes saliva directly into the oral cavity, rather than into the bloodstream like endocrine glands. The pancreas (A) secretes hormones such as insulin and glucagon into the bloodstream. The testes (B) produce hormones like testosterone that are released into the bloodstream. The parathyroid (D) gland secretes parathyroid hormone directly into the bloodstream to regulate calcium levels. In summary, the salivary gland is not considered an endocrine gland because it does not secrete hormones directly into the bloodstream for systemic effects.
What is the stimulus for the release of insulin?
- A. Low plasma levels of calcium
- B. High plasma levels of potassium
- C. High plasma levels of glucose
- D. Low blood volume
Correct Answer: C
Rationale: The correct answer is C: High plasma levels of glucose. When blood glucose levels rise after a meal, pancreatic beta cells sense this increase and release insulin to facilitate glucose uptake into cells for energy production or storage. This is known as the glucose-stimulated insulin release mechanism. Low plasma levels of calcium (choice A), high plasma levels of potassium (choice B), and low blood volume (choice D) do not directly stimulate insulin release and are unrelated to the regulation of insulin secretion.
Common nonspecific manifestations that may alert the nurse to endocrine dysfunction include
- A. goiter and alopecia.
- B. exophthalmos and tremors.
- C. weight loss, fatigue, and depression.
- D. polyuria, polydipsia, and polyphagia.
Correct Answer: C
Rationale: Weight loss, fatigue, and depression are nonspecific symptoms that can point to various endocrine disorders, including thyroid and adrenal conditions.