What gland requires iodine in order to produce its hormones?
- A. Adrenal cortex
- B. Pancreas
- C. Parathyroid glands
- D. Thyroid gland
Correct Answer: D
Rationale: The correct answer is D: Thyroid gland. The thyroid gland requires iodine to produce its hormones, such as thyroxine and triiodothyronine, which are essential for regulating metabolism, growth, and development. Iodine is a crucial component of these thyroid hormones. The other choices (A: Adrenal cortex, B: Pancreas, C: Parathyroid glands) do not require iodine for hormone production and are not involved in the synthesis of thyroid hormones. Therefore, the correct answer is the thyroid gland because it specifically relies on iodine for hormone synthesis, making it the only gland in the list that fits this criteria.
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Which of the following statements regarding pituitary hormones is FALSE?
- A. Hyposecretion of follicle-stimulating hormone (FSH) or luteinizing hormone (LH) leads to sterility in both males and females.
- B. Antidiuretic hormone (ADH), released by the posterior pituitary, causes urine volume to increase as blood volume decreases.
- C. Oxytocin is released in significant amounts ONLY during childbirth and nursing in woman.
- D. Luteinizing hormone, an anterior pituitary hormone, triggers ovulation of an egg from the ovary and causes the ruptured follicle to produce progesterone and some estrogens.
Correct Answer: B
Rationale: The correct answer is B because antidiuretic hormone (ADH) actually causes urine volume to decrease as blood volume decreases, not increase. ADH acts on the kidneys to reabsorb water, leading to concentrated urine and conservation of body fluids.
Rationale summary:
A: True, hyposecretion of FSH or LH can lead to sterility in both males and females.
C: False, oxytocin is also released during sexual activity, breastfeeding, social bonding, and stress responses, not just during childbirth and nursing.
D: True, luteinizing hormone triggers ovulation and stimulates the production of progesterone and some estrogens.
Muscarinic receptors can be stimulated by the following drugs EXCEPT:
- A. Pilocarpine
- B. Hyoscine
- C. Acetylcholine
- D. Neostigmine
Correct Answer: B
Rationale: The correct answer is B: Hyoscine. Muscarinic receptors can be stimulated by Pilocarpine, Acetylcholine, and Neostigmine, as they are known agonists of muscarinic receptors. Hyoscine, also known as scopolamine, is an antagonist of muscarinic receptors, blocking their stimulation. This makes it the exception among the listed drugs.
All the following adverse effects can be produced by beta-blockers EXCEPT:
- A. Hypotension
- B. Heart failure
- C. Bronchodilation
- D. Heart block
Correct Answer: C
Rationale: The correct answer is C: Bronchodilation. Beta-blockers primarily work by blocking the beta-adrenergic receptors, leading to a decrease in heart rate and contractility. This can result in adverse effects such as hypotension, heart failure, and heart block due to the reduced cardiac output. However, bronchodilation is not a typical adverse effect of beta-blockers. In fact, beta-blockers can cause bronchoconstriction in patients with underlying respiratory conditions like asthma, making choice C the correct answer. Choices A, B, and D are incorrect because hypotension, heart failure, and heart block are known adverse effects associated with beta-blockers due to their mechanism of action on the cardiovascular system.
The relatively constant internal environment of the body is maintained by _______.
- A. negative feedback.
- B. positive feedback.
- C. homeostasis.
- D. metabolism.
Correct Answer: C
Rationale: The correct answer is C: homeostasis. Homeostasis refers to the body's ability to maintain a stable internal environment despite external changes. It involves various physiological mechanisms to regulate temperature, pH, blood sugar levels, and more. Negative feedback (choice A) is a key component of homeostasis, where the body reverses a deviation from the set point to restore balance. Positive feedback (choice B) amplifies a response and does not contribute to maintaining stability. Metabolism (choice D) is the sum of all chemical processes in the body and is necessary for homeostasis but does not directly regulate the internal environment.
A patient presents with tiredness, weakness, anorexia, apathy, abdominal pain, hyperpigmentation and postural hypertension. Upon infection he appears to be in cardiogenic shock and his blood volume is depleted. His sodium levels are low, potassium levels are high. Which of the following would also be elevated?
- A. TSH
- B. T4
- C. Adrenal hormone
- D. ACTH
Correct Answer: D
Rationale: The correct answer is D: ACTH. In this scenario, the patient is exhibiting symptoms of adrenal insufficiency, specifically Addison's disease. ACTH levels would be elevated due to the lack of negative feedback from cortisol, which is typically low in adrenal insufficiency. TSH (A) and T4 (B) would be normal or low due to the hypofunction of the adrenal gland, not the thyroid. Adrenal hormones (C) would be low in adrenal insufficiency, not elevated.