Nokea
The most important regulator of electrolyte concentrations in extracellular fluids is ________.
- A. insulin
- B. aldosterone
- C. glucagon
- D. cortisol
Correct Answer: B
Rationale: The correct answer is B: aldosterone. Aldosterone is a hormone produced by the adrenal glands that plays a key role in regulating electrolyte concentrations in extracellular fluids. It specifically acts on the kidneys to increase the reabsorption of sodium and water while promoting the excretion of potassium. This helps to maintain the balance of electrolytes in the body. Insulin, glucagon, and cortisol do not directly regulate electrolyte concentrations in extracellular fluids. Insulin regulates blood sugar levels, glucagon regulates glucose release from the liver, and cortisol is involved in stress response and metabolism. Therefore, aldosterone is the most important regulator of electrolyte concentrations in extracellular fluids.
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Which of the following stimulates the release of parathyroid hormone?
- A. TSH from the posterior pituitary gland
- B. high levels of calcium in the blood
- C. calcitonin from the anterior pituitary gland
- D. low levels of calcium in the blood
Correct Answer: D
Rationale: The correct answer is D: low levels of calcium in the blood. Parathyroid hormone is released in response to low blood calcium levels to help increase calcium levels by promoting its release from bones and enhancing its absorption in the intestines. This response helps maintain calcium homeostasis. TSH from the posterior pituitary gland (choice A) is not related to parathyroid hormone release. High levels of calcium in the blood (choice B) would not stimulate parathyroid hormone release as it is released in response to low calcium levels. Calcitonin from the anterior pituitary gland (choice C) actually works in opposition to parathyroid hormone by promoting calcium deposition in bones and decreasing blood calcium levels.
The production and release of hormones caused by a chemical such as calcium is a _____ mechanism.
- A. humoral
- B. neural
- C. sensory
- D. hormonal
Correct Answer: A
Rationale: The correct answer is A: humoral. Humoral regulation refers to the control of physiological processes by substances in the blood, such as hormones. In this case, the production and release of hormones in response to a chemical like calcium is an example of humoral mechanism. This choice is correct because it specifically involves the blood-borne substances affecting hormone production.
Choices B, C, and D are incorrect because neural regulation (B) involves the nervous system controlling physiological processes, sensory regulation (C) refers to sensory input influencing responses, and hormonal regulation (D) involves feedback loops within the endocrine system, not directly related to blood-borne substances like calcium.
The anterior pituitary gland:
- A. is called the neurohypophysis.
- B. releases ADH and oxytocin.
- C. secretes releasing hormones.
- D. is connected to the hypothalamus by the portal capillaries.
Correct Answer: D
Rationale: Step-by-step rationale:
1. The anterior pituitary gland is connected to the hypothalamus by the portal capillaries.
2. This connection allows for the transport of releasing hormones from the hypothalamus to the anterior pituitary.
3. Releasing hormones stimulate the anterior pituitary to release specific hormones.
4. This communication pathway is essential for regulating hormone production and maintaining homeostasis.
Summary of other choices:
A: Incorrect. The neurohypophysis refers to the posterior pituitary, not the anterior pituitary.
B: Incorrect. ADH and oxytocin are released from the posterior pituitary, not the anterior pituitary.
C: Incorrect. Releasing hormones are produced by the hypothalamus, not the anterior pituitary.
The clusters of cells in the pancreas that produce hormones are the:
- 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 are clusters of cells in the pancreas responsible for producing hormones like insulin and glucagon. The islets regulate blood sugar levels. Nodules (A) are not specific to the pancreas. Pancreatic medulla (C) and pancreatic cortex (D) do not refer to the specific clusters of cells in the pancreas that produce hormones.
The following plant alkaloids give derivatives which are used to treat migraine:
- A. Vinca alkaloids
- B. Digitalis glycosides
- C. Stramonium alkaloids
- D. Ergot alkaloids
Correct Answer: D
Rationale: The correct answer is D: Ergot alkaloids. Ergot alkaloids, such as ergotamine and dihydroergotamine, are known to be effective in treating migraines by constricting blood vessels in the brain. This helps to reduce the intensity of migraine headaches. Vinca alkaloids (A) are used in cancer treatment, digitalis glycosides (B) in heart conditions, and stramonium alkaloids (C) in asthma and spasms, but they are not commonly associated with migraine treatment.