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Which gland secretes melatonin and is concerned with our biological rhythms?
- A. Pancreas
- B. Adenohypophysis
- C. Pineal gland
- D. Adrenal gland
Correct Answer: C
Rationale: The correct answer is C: Pineal gland. The pineal gland is responsible for secreting melatonin, a hormone that regulates our biological rhythms such as sleep-wake cycles. This gland is located in the brain and plays a crucial role in maintaining our circadian rhythm. The other choices are incorrect because:
A: The pancreas secretes insulin and glucagon to regulate blood sugar levels, not melatonin.
B: The adenohypophysis, or anterior pituitary gland, secretes various hormones but not melatonin.
D: The adrenal gland produces hormones like cortisol and adrenaline, not melatonin.
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Which of the Following Hormones Are Expected to Increase in the Body After Consuming a Banana Split?
- A. Prolactin
- B. Glucagon
- C. Insulin
- D. Thyroid hormone
Correct Answer: C
Rationale: Step-by-step rationale for why choice C (Insulin) is correct:
1. A banana split is high in carbohydrates and sugar.
2. Consuming carbohydrates and sugar triggers an increase in blood glucose levels.
3. Insulin is released by the pancreas in response to high blood glucose levels to facilitate the uptake of glucose into cells for energy.
4. Therefore, after consuming a banana split, insulin levels in the body are expected to increase to regulate blood glucose levels.
Summary of why other choices are incorrect:
- A: Prolactin is a hormone involved in lactation and is not directly related to consuming a banana split.
- B: Glucagon is released in response to low blood glucose levels to increase blood sugar, opposite of what is expected after consuming a banana split.
- D: Thyroid hormone regulates metabolism and is not directly influenced by consuming a banana split.
A patient who recently had a calcium oxalate renal stone had a bone density study, which showed a decrease in her bone density. What endocrine problem could this patient have?
- A. SIADH
- B. Cushing syndrome
- C. Hypothyroidism
- D. Hyperparathyroidism
Correct Answer: D
Rationale: Hyperparathyroidism can lead to bone demineralization, which may cause a decrease in bone density, and is often associated with kidney stones.
A man has been searching for an aphrodisiac or some other agent to enhance 'sexual performance' discovers yohimbine. He consumes the drug in excess and develops symptoms of toxicity that require your intervention. Which of the following should you expect as a response to this drug?
- A. Bradycardia
- B. Bronchoconstriction
- C. Excessive secretions by exocrine glands (salivary, lacrimal, etc.)
- D. Hypertension
Correct Answer: D
Rationale: The correct answer is D: Hypertension. Yohimbine is a known alpha-2 adrenergic antagonist, leading to increased sympathetic activity and consequently, hypertension. This occurs due to increased norepinephrine release and vasoconstriction. Bradycardia (A) is unlikely as yohimbine usually causes tachycardia. Bronchoconstriction (B) is not a common effect of yohimbine. Excessive secretions by exocrine glands (C) are not associated with yohimbine toxicity.
The endocrine gland responsible for the body’s circadian rhythm is:
- A. Thymus
- B. Pineal
- C. Parathyroid
- D. Pituitary
Correct Answer: B
Rationale: The correct answer is B: Pineal gland. The pineal gland secretes melatonin, a hormone that regulates the body's circadian rhythm. Melatonin helps control the sleep-wake cycle, making the pineal gland crucial for maintaining our internal body clock. The other choices, Thymus, Parathyroid, and Pituitary glands, are not directly involved in regulating circadian rhythms. Thymus is responsible for immune function, Parathyroid regulates calcium levels, and Pituitary gland controls various hormones but not specifically circadian rhythm. Hence, the pineal gland is the correct choice for this question.
What is the speed of the wave?
- A. 1.5cm/s
- B. 3.0cm/s
- C. 300 cm/s
- D. 600 cm/s
Correct Answer: D
Rationale: The correct answer is D: 600 cm/s. The speed of a wave is determined by the formula speed = frequency x wavelength. Given that the frequency and wavelength are constant, the only way to increase the speed is to increase the frequency or the wavelength. Since both frequency and wavelength are fixed, the speed can only be increased by increasing both. Choice D, 600 cm/s, is double the speed of choice C, 300 cm/s, which indicates that both frequency and wavelength have been doubled, leading to the correct answer. Choices A and B are too low to be correct, as they are not consistent with the principles of wave speed calculation.