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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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.
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.
You are caring for a patient who is post-hypophysectomy for hyperpituitarism. Which post-operative finding requires immediate intervention?
- A. Presence of glucose in nasal drainage
- B. Nasal packing present in nares
- C. Urine output of 40-50 mL per hour
- D. Patient complaints of thirst
Correct Answer: A
Rationale: The presence of glucose in nasal drainage after hypophysectomy may indicate a cerebrospinal fluid leak, which requires immediate medical intervention.
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.
Antidiuretic hormone (ADH) and oxytocin:
- A. are secreted by the neurohypophysis.
- B. are mineralocorticoids.
- C. are secreted by the islets of Langerhans.
- D. stimulate the kidney to excrete Na+ and water.
Correct Answer: A
Rationale: Step-by-step rationale for choice A being correct:
1. ADH and oxytocin are peptide hormones.
2. They are synthesized in the hypothalamus.
3. They are transported and stored in the neurohypophysis.
4. Upon stimulation, they are released from the neurohypophysis.
5. Therefore, both ADH and oxytocin are indeed secreted by the neurohypophysis.
Summary of why other choices are incorrect:
B: ADH and oxytocin are not mineralocorticoids; they regulate water balance and uterine contractions, respectively.
C: Islets of Langerhans secrete insulin and glucagon, not ADH or oxytocin.
D: ADH promotes water reabsorption in the kidneys, opposite to excreting Na+ and water.