Nokea
Mineralcorticoids
- A. are produced in the adrenal cortex.
- B. are steroid hormones.
- C. help regulate the homeostasis of sodium and potassium.
- D. All of the above.
Correct Answer: D
Rationale: 1. Mineralocorticoids are hormones produced in the adrenal cortex (A).
2. They are steroid hormones (B) that specifically regulate sodium and potassium homeostasis (C).
3. Therefore, the correct answer is D, as mineralocorticoids encompass all these characteristics. Other choices are incorrect as they do not fully encompass the functions and characteristics of mineralocorticoids.
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Propranolol is useful in the treatment of all of the following conditions EXCEPT:
- A. Hypertension
- B. Anxiety
- C. Heart block
- D. Angina of effort
Correct Answer: C
Rationale: Propranolol is a non-selective beta-blocker that slows the heart rate and reduces blood pressure. Heart block refers to a condition where the electrical signals in the heart are delayed or blocked. Propranolol can worsen heart block by further slowing down the heart rate, making it inappropriate for this condition. Therefore, the correct answer is C.
A: Propranolol is used to treat hypertension by reducing blood pressure.
B: Propranolol is effective in managing anxiety symptoms by blocking the physical manifestations of anxiety, such as rapid heart rate.
D: Propranolol is beneficial in treating angina of effort by reducing the workload of the heart and improving blood flow to the heart muscle.
In summary, the other choices (A, B, D) are correct uses of propranolol, making C the exception due to its potential to worsen heart block.
Gastrin secretion is stimulated by all but:
- A. luminal peptides
- B. vagal discharge
- C. luminal acid
- D. phenylalanine
Correct Answer: C
Rationale: The correct answer is C: luminal acid. Gastrin secretion is primarily stimulated by the presence of luminal peptides and vagal discharge. Luminal acid inhibits gastrin secretion through negative feedback mechanisms. Phenylalanine does not directly stimulate gastrin secretion. In summary, luminal acid is the correct answer because it acts as an inhibitory factor for gastrin secretion, whereas the other choices are known stimulatory factors.
Hormones produced by the hypothalamus and secreted by the posterior pituitary include:
- A. ADH and aldosterone
- B. ADH and oxytocin
- C. oxytocin and prolactin
- D. cortisol and aldosterone
Correct Answer: B
Rationale: Step 1: The hormones produced by the hypothalamus and secreted by the posterior pituitary are ADH (vasopressin) and oxytocin.
Step 2: ADH regulates water balance by increasing water reabsorption in the kidneys.
Step 3: Oxytocin is involved in uterine contractions during childbirth and milk ejection during breastfeeding.
Step 4: Therefore, choice B (ADH and oxytocin) is correct.
Summary:
- Choice A (ADH and aldosterone) is incorrect because aldosterone is produced by the adrenal glands, not the posterior pituitary.
- Choice C (oxytocin and prolactin) is incorrect because prolactin is produced by the anterior pituitary.
- Choice D (cortisol and aldosterone) is incorrect because cortisol is produced by the adrenal glands, not the posterior pituitary.
Secretion of oxytocin is increased by
- A. milk ejection
- B. dilation of the cervix
- C. increased prolactin levels
- D. increased extracellular fluid (ECF) volume
Correct Answer: B
Rationale: Certainly! The secretion of oxytocin is increased by the dilation of the cervix. When the cervix dilates during childbirth, it triggers the release of oxytocin from the posterior pituitary gland. This hormone plays a crucial role in stimulating uterine contractions during labor and delivery. Milk ejection (choice A) is primarily regulated by oxytocin but does not directly increase its secretion. Increased prolactin levels (choice C) stimulate milk production, not oxytocin secretion. Increased extracellular fluid (ECF) volume (choice D) is not directly related to oxytocin secretion.
Which of the following is NOT a mechanism of hormone action?
- A. plasma membrane permeability changes
- B. cellular mutations occur
- C. enzymes are activated or inactivated
- D. mitosis is stimulated
Correct Answer: B
Rationale: The correct answer is B: cellular mutations occur. Hormones typically act through binding to specific receptors on target cells to initiate a signaling cascade. This process does not involve inducing mutations in the cell's DNA. Plasma membrane permeability changes, enzyme activation/inactivation, and stimulation of mitosis are all well-established mechanisms of hormone action. Therefore, B is the correct answer as it does not align with the usual mechanisms by which hormones exert their effects.