Endocrine System Exam Questions Answers

Endocrine System Exam Questions Answers Related

Review Endocrine System Exam Questions Answers related questions and content

When blood Calcium level is elevated, the body is in a state of hypercalcemia. Which gland is responsible for secreting a hormone to return Ca2+ level to normal and therefore maintain homeostasis?

  • A. Hypothalamus
  • B. Pituitary
  • C. Thyroid
  • D. Parathyroid
Correct Answer: c

Rationale: The correct answer is D: Parathyroid. The parathyroid gland secretes parathyroid hormone (PTH) when blood calcium levels are elevated. PTH acts to increase calcium reabsorption in the kidneys, release calcium from bones, and enhance calcium absorption in the intestines, ultimately lowering blood calcium levels back to normal.

A: The hypothalamus plays a role in regulating body temperature, thirst, hunger, and circadian rhythms, but not in calcium homeostasis.
B: The pituitary gland secretes various hormones, but none specifically involved in regulating blood calcium levels.
C: The thyroid gland secretes thyroid hormones that regulate metabolism and growth, not calcium levels.

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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.

Pilocarpine is used in the treatment of:

  • A. Heart failure
  • B. Bronchial asthma
  • C. Urinary obstruction
  • D. Glaucoma
Correct Answer: D

Rationale: Pilocarpine is a parasympathomimetic agent that stimulates the muscarinic receptors in the eye, causing pupillary constriction and reducing intraocular pressure. This mechanism of action makes it effective in treating glaucoma. Heart failure (A), bronchial asthma (B), and urinary obstruction (C) are not indications for pilocarpine use based on its pharmacological properties and effects.

Which statement about the reaction is correct?

  • A. It is endothermic and thermal energy is absorbed from the surroundings.
  • B. It is endothermic and thermal energy is transferred to the surroundings.
  • C. It is exothermic and thermal energy is absorbed from the surroundings.
  • D. It is exothermic and thermal energy is transferred to the surroundings.
Correct Answer: A

Rationale: The correct answer is A because an endothermic reaction absorbs thermal energy from the surroundings to proceed. In an endothermic reaction, the products have higher potential energy than the reactants, requiring energy input. Choice B is incorrect as endothermic reactions do not transfer thermal energy to the surroundings. Choices C and D are incorrect as they describe exothermic reactions, where thermal energy is released to the surroundings.

If farmers exposed to 'insecticides' ('irreversible' cholinesterase inhibitors) are given medical kits that contain atropine. Which one of the following effects of the cholinesterase inhibitor will NOT be blocked by the atropine?

  • A. Bronchoconstriction / bronchospasm
  • B. Increased bladder/urinary tract activity
  • C. Increased bowel motility (i.e., diarrhea)
  • D. Skeletal muscle overstimulation, eventually leading to skeletal muscle paralysis
Correct Answer: D

Rationale: The correct answer is D. Atropine blocks the effects of cholinesterase inhibitors on muscarinic receptors but not on nicotinic receptors, which are responsible for skeletal muscle overstimulation. Atropine can block bronchoconstriction, increased bladder activity, and increased bowel motility as they are mediated by muscarinic receptors. Therefore, the effects on skeletal muscle overstimulation, leading to paralysis, will not be blocked by atropine.

Which of the following elements is required for the synthesis of thyroid hormone?

  • A. copper
  • B. iodine
  • C. sulfur
  • D. zinc
Correct Answer: B

Rationale: The correct answer is B: iodine. Iodine is an essential element required for the synthesis of thyroid hormone. Thyroid hormones such as thyroxine (T4) and triiodothyronine (T3) contain iodine atoms. Without sufficient iodine, the thyroid gland cannot produce these hormones, leading to thyroid disorders like hypothyroidism or goiter. Copper (A), sulfur (C), and zinc (D) are not directly involved in the synthesis of thyroid hormone. Copper is important for enzyme function, sulfur is present in amino acids, and zinc is involved in various cellular processes but not specifically in thyroid hormone synthesis.

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