Nokea
The endocrine gland responsible for the body's circadian rhythm is the:
- A. Thymus gland.
- B. Pineal gland.
- C. Parathyroid gland.
- D. Pituitary gland.
Correct Answer: B
Rationale: The correct answer is B: Pineal gland. The pineal gland produces melatonin, a hormone that regulates the body's circadian rhythm, including sleep-wake cycles. This gland is sensitive to light and darkness, influencing the body's internal clock.
A: Thymus gland is responsible for immune function, not circadian rhythm.
C: Parathyroid gland regulates calcium levels in the body, not circadian rhythm.
D: Pituitary gland controls various other hormones but not specifically circadian rhythm.
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Which of the following is NOT true of Cushing syndrome?
- A. trunk (torso) becomes obese
- B. basic blood pH
- C. moon-shaped face
- D. hyposecretion of adrenal cortex hormones.
Correct Answer: D
Rationale: Step-by-step rationale:
1. Cushing syndrome is characterized by hypersecretion of adrenal cortex hormones, not hyposecretion.
2. Option D states hyposecretion, which is incorrect for Cushing syndrome.
3. Trunk obesity, moon-shaped face, and alkalosis (basic blood pH) are characteristic features of Cushing syndrome.
4. Thus, option D is the correct answer because it is not a true characteristic of Cushing syndrome.
Summary:
Option D is incorrect because Cushing syndrome is associated with hypersecretion of adrenal cortex hormones, not hyposecretion. Options A, B, and C are true characteristics of Cushing syndrome, making them incorrect choices.
Narcolepsy is treated with:
- A. Amphetamine
- B. Adrenaline
- C. Isoprenaline
- D. Salbutamol
Correct Answer: A
Rationale: The correct answer is A: Amphetamine. Amphetamine is a central nervous system stimulant that helps manage narcolepsy symptoms by promoting wakefulness. It increases levels of neurotransmitters like dopamine and norepinephrine, enhancing alertness. Adrenaline (B), Isoprenaline (C), and Salbutamol (D) are not typically used to treat narcolepsy as they do not directly target the underlying cause of excessive daytime sleepiness. Adrenaline and Isoprenaline are more commonly used for acute situations like anaphylaxis or cardiac arrest. Salbutamol is a bronchodilator used for conditions like asthma.
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.
Virtually all of the protein or amino acid-based hormones exert their effects through intracellular ________.
- A. ions
- B. deactivators
- C. nucleotides
- D. second messengers
Correct Answer: D
Rationale: The correct answer is D: second messengers. Protein or amino acid-based hormones are unable to pass through the cell membrane due to their large size and hydrophilic nature. Therefore, they bind to specific receptors on the cell surface, triggering a series of events that lead to the production of second messengers inside the cell. These second messengers, such as cyclic AMP or calcium ions, then transmit the hormonal signal to the target cell's interior to initiate a physiological response. Choices A, B, and C are incorrect because protein or amino acid-based hormones do not directly exert their effects through ions, deactivators, or nucleotides intracellularly.
Which of the following is not a function of insulin?
- A. Lowering blood glucose levels
- B. Promoting protein synthesis
- C. Simulating hepatic gluconeogenesis
- D. Promoting fatty acid synthesis
Correct Answer: C
Rationale: The correct answer is C: Stimulating hepatic gluconeogenesis. Insulin's primary function is to lower blood glucose levels by promoting glucose uptake in cells and inhibiting gluconeogenesis in the liver. Choice A is correct as insulin helps lower blood glucose levels. Choice B is correct as insulin promotes protein synthesis. Choice D is correct as insulin promotes fatty acid synthesis to store excess glucose as fat. Therefore, choice C is incorrect as insulin actually inhibits hepatic gluconeogenesis rather than stimulating it.