Which produces the majority of salivary volume?
- A. lingual glands
- B. sublingual
- C. parotid
- D. submandibular
Correct Answer: D
Rationale: The correct answer is D, submandibular glands, as they produce the majority of salivary volume. These glands are the largest of the major salivary glands and secrete saliva rich in enzymes and mucin, contributing significantly to the total saliva volume. The lingual glands (A) are minor salivary glands located in the tongue and contribute a small portion of saliva. The sublingual glands (B) are also minor salivary glands located beneath the tongue, producing a smaller volume compared to the submandibular glands. The parotid glands (C) are another major salivary gland, but they produce a lesser volume of saliva compared to the submandibular glands.
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The cluster of cells in the pancreas that secrete hormones are:
- A. Nodules
- B. Islets of Langerhans
- C. Pancreatic medulla
- D. Pancreatic cortex
Correct Answer: B
Rationale: The correct answer is B: Islets of Langerhans. These clusters of cells in the pancreas are responsible for secreting hormones such as insulin and glucagon. Islets of Langerhans contain different types of cells that regulate blood sugar levels. Nodules (A), pancreatic medulla (C), and pancreatic cortex (D) are not associated with hormone secretion in the pancreas. Nodules are more general and not specific to the pancreas, while pancreatic medulla and cortex do not house the endocrine cells responsible for hormone secretion.
Peptide hormones _______________.
- A. are hydrophilic
- B. cannot enter the target cell
- C. bind to a receptor on the cell surface
- D. all of these
Correct Answer: D
Rationale: The correct answer is D because peptide hormones are hydrophilic molecules that cannot pass through the cell membrane, so they bind to receptors on the cell surface to initiate signaling pathways within the cell. Therefore, they are unable to enter the target cell like lipid-soluble hormones do. By binding to specific receptors on the cell surface, peptide hormones trigger a series of events that ultimately lead to a cellular response. Therefore, all of the given statements are true, making D the correct choice.
Which of the following drugs does not pass the blood-brain barrier:
- A. Ephedrine
- B. Propranolol
- C. Clonidine
- D. Guanethidine
Correct Answer: D
Rationale: The correct answer is D: Guanethidine. Guanethidine is a quaternary amine, which prevents it from passing the blood-brain barrier due to its charge. The blood-brain barrier is selective and only allows certain molecules to pass through. In contrast, choices A, B, and C (Ephedrine, Propranolol, Clonidine) are all capable of crossing the blood-brain barrier to some extent due to their chemical properties. Ephedrine is a weak base, Propranolol is lipophilic, and Clonidine is relatively small in size, allowing them to penetrate the blood-brain barrier.
Which of the following is associated with hyperthyroidism?
- A. Weight gain
- B. Dry skin
- C. Heat intolerance
- D. Bradycardia
Correct Answer: C
Rationale: Step-by-step rationale:
1. Hyperthyroidism is an overactive thyroid gland.
2. Heat intolerance is a common symptom due to increased metabolic rate.
3. Weight gain is associated with hypothyroidism, not hyperthyroidism.
4. Dry skin is more commonly seen in hypothyroidism.
5. Bradycardia (slow heart rate) is not typical in hyperthyroidism.
Summary:
Choice C, heat intolerance, is associated with hyperthyroidism due to increased metabolic activity. Choices A, B, and D are incorrect as they are more commonly associated with hypothyroidism or other conditions.
The only insulin that can be administered intravenously is
- A. Lente
- B. Semi-Lente
- C. regular
- D. NPH
Correct Answer: C
Rationale: Only regular insulin is approved for intravenous administration due to its rapid onset and shorter duration of action.