Nokea
Which of the following hormones helps conserve water during dehydration?
- A. Atrial natriuretic peptide
- B. Oxytocin
- C. Aldosterone
- D. Thyroxine
Correct Answer: C
Rationale: Aldosterone is the correct answer because it acts on the kidneys to increase reabsorption of sodium and water, helping conserve water during dehydration. Atrial natriuretic peptide promotes sodium excretion, oxytocin is involved in labor and milk ejection, and thyroxine regulates metabolism.
You may also like to solve these questions
Sometimes prolonged excessive exposure to high hormone concentrations causes a phenomenon known as ________.
- A. diabetes mellitus
- B. cellular inhibition
- C. down-regulation
- D. metabolism of protein kinases
Correct Answer: C
Rationale: The correct answer is C: down-regulation. Prolonged exposure to high hormone concentrations can lead to down-regulation, where cells decrease their responsiveness to the hormone by reducing the number of hormone receptors. This is a regulatory mechanism to prevent overstimulation.
A: Diabetes mellitus is a chronic condition characterized by high blood sugar levels, usually caused by insulin deficiency or insulin resistance, not directly related to prolonged exposure to high hormone concentrations.
B: Cellular inhibition is a broad term that may refer to various cellular processes being inhibited, but it is not a specific phenomenon resulting from prolonged exposure to high hormone concentrations.
D: Metabolism of protein kinases is a cellular process involved in signal transduction, but it is not a direct consequence of prolonged exposure to high hormone concentrations.
Hypothyroidism in children:
- A. Cretinism
- B. Myxoedema
- C. Graves disease
- D. Acromegaly
Correct Answer: A
Rationale: The correct answer is A: Cretinism. Cretinism is a condition of severe hypothyroidism during childhood, leading to stunted growth, intellectual disability, and physical deformities. Myxoedema refers to severe hypothyroidism in adults, not children. Graves disease is a form of hyperthyroidism, opposite of hypothyroidism. Acromegaly is a condition caused by excess growth hormone, not related to thyroid dysfunction. Therefore, Cretinism is the correct answer for hypothyroidism in children due to its specific characteristics and presentation.
The posterior pituitary gland receives hormone messages from the hypothalamus via ________.
- A. a capillary network
- B. neurons that extend from the hypothalamus to the pituitary
- C. Schwann cells
- D. both a and b
Correct Answer: B
Rationale: The correct answer is B: neurons that extend from the hypothalamus to the pituitary. The hypothalamus produces hormones that are stored and released by the posterior pituitary gland. This communication is facilitated by specialized neurons that extend from the hypothalamus to the pituitary, forming the hypothalamic-pituitary axis. These neurons release hormones into the bloodstream, which then reach the posterior pituitary gland and stimulate the release of its stored hormones. Choice A is incorrect because the posterior pituitary does not directly receive messages through a capillary network. Choice C is incorrect as Schwann cells are responsible for myelinating peripheral nerves, not hormone communication. Choice D is incorrect because while the hypothalamus communicates with the pituitary gland through neurons, it does not involve a capillary network.
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.
The posterior pituitary stores and releases:
- A. Growth hormone and prolactin.
- B. Prolactin and oxytocin.
- C. Oxytocin and antidiuretic hormone (ADH).
- D. ADH and growth hormone.
Correct Answer: C
Rationale: The correct answer is C: Oxytocin and antidiuretic hormone (ADH). The posterior pituitary stores and releases oxytocin and ADH, also known as vasopressin. Oxytocin is involved in uterine contractions and milk ejection, while ADH regulates water reabsorption in the kidneys. Choices A, B, and D are incorrect because the posterior pituitary does not store or release growth hormone or prolactin.