Nokea
Factors that inhibit TSH release do not include ________.
- A. growth hormone-inhibiting hormone (GHIH)
- B. rising levels of glucocorticoids
- C. somatostatin
- D. excessively high blood iodine concentrations
Correct Answer: D
Rationale: The correct answer is D: excessively high blood iodine concentrations. High blood iodine levels do not inhibit TSH release; they actually stimulate it. Growth hormone-inhibiting hormone (GHIH), rising levels of glucocorticoids, and somatostatin are all factors that inhibit TSH release. GHIH inhibits TSH release by acting on the pituitary gland. Glucocorticoids have a negative feedback effect on the hypothalamus and pituitary gland, reducing TSH release. Somatostatin inhibits the release of various hormones, including TSH.
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The following statements concerning prazosin and phentolamine are correct EXCEPT:
- A. Both antagonize alpha1-receptors
- B. Both cause the same degree of tachycardia
- C. Both decrease blood pressure
- D. Both are competitive antagonists
Correct Answer: B
Rationale: Correct Answer: B
Rationale:
1. Prazosin and phentolamine both antagonize alpha1-receptors, leading to vasodilation and decreased blood pressure.
2. Both drugs are competitive antagonists, competing with norepinephrine at alpha1-receptors.
3. However, phentolamine causes reflex tachycardia due to its non-selective alpha-adrenergic blockade, unlike prazosin.
4. Therefore, the statement that both cause the same degree of tachycardia is incorrect based on their pharmacological differences.
Select the correct statement about the structure or function of chemical messengers.
- A. Prostaglandins are biologically active peptides.
- B. Modified cholesterol forms the main structural component of the peptone hormones.
- C. An amino acid derivative can be a hormone.
- D. An example of a paracrine is testosterone.
Correct Answer: C
Rationale: The correct answer is C: An amino acid derivative can be a hormone. This statement is correct because many hormones are derived from amino acids, such as thyroid hormones (derived from tyrosine) and epinephrine (derived from phenylalanine). Hormones can be derived from various sources, including amino acids, peptides, lipids, and even gases.
Explanation of other choices:
A: Prostaglandins are not biologically active peptides; they are lipid compounds derived from fatty acids.
B: Modified cholesterol does not form the main structural component of peptone hormones; peptides are the main structural components of peptide hormones.
D: Testosterone is a steroid hormone and not an example of a paracrine, which is a type of chemical messenger that acts on nearby cells.
Insulin:
- A. stimulates the formation of glycogen.
- B. increases the transport of glucose into a cell.
- C. stimulates the synthesis of proteins and fats.
- D. all is applicable.
Correct Answer: D
Rationale: Certainly! The correct answer is D because insulin plays a crucial role in various metabolic processes. Firstly, insulin stimulates the formation of glycogen by promoting the uptake of glucose into the liver and muscles for storage. Secondly, it increases the transport of glucose into cells, regulating blood sugar levels. Lastly, insulin also stimulates the synthesis of proteins and fats by promoting the uptake of amino acids and fatty acids into cells. Therefore, all the statements in option D are correct based on the functions of insulin.
Endocrine system consists of ductless glands which secrete:
- A. Enzymes
- B. Hormones
- C. Electrolytes
- D. Chemicals
Correct Answer: B
Rationale: The correct answer is B: Hormones. The endocrine system consists of ductless glands that secrete hormones directly into the bloodstream to regulate various bodily functions. Hormones are chemical messengers that help control metabolism, growth, development, mood, and other physiological processes. Enzymes (choice A) are not secreted by the endocrine system but by exocrine glands. Electrolytes (choice C) are ions essential for various bodily functions but are not directly secreted by glands of the endocrine system. Choice D, chemicals, is too broad and vague as all substances can be considered chemicals.
The left suprarenal vein drains into which of the following?
- A. Superior mesenteric vein
- B. Inferior hemiazygos
- C. Inferior vena cava
- D. Left renal vein
Correct Answer: D
Rationale: The correct answer is D: Left renal vein. The left suprarenal vein drains into the left renal vein because they are anatomically close and share a common blood supply. The left suprarenal vein carries blood from the left adrenal gland, while the left renal vein receives blood from the left kidney. This anatomical proximity allows for efficient drainage of blood from the adrenal gland into the renal vein for further circulation. Choices A, B, and C are incorrect because the left suprarenal vein does not typically drain into the superior mesenteric vein, inferior hemiazygos, or inferior vena cava.