Nokea
Which of the following is true about calcium homeostasis?
- A. Increased calcitonin levels will cause increased blood calcium levels.
- B. High calcium levels cause bone resorption.
- C. Parathyroid hormone causes an increase in osteoblast activity.
- D. Parathyroid hormone is the single most important regulator of calcium levels in the blood.
Correct Answer: D
Rationale: The correct answer is D: Parathyroid hormone is the single most important regulator of calcium levels in the blood. Parathyroid hormone plays a crucial role in maintaining calcium homeostasis by stimulating bone resorption, increasing calcium reabsorption in the kidneys, and activating vitamin D to enhance calcium absorption in the intestines. It acts to raise blood calcium levels when they are low.
Explanation for other choices:
A: Increased calcitonin levels actually lower blood calcium levels by promoting calcium deposition in bones.
B: High calcium levels do not cause bone resorption; it is actually the opposite as mentioned in choice D.
C: Parathyroid hormone does not increase osteoblast activity; it primarily affects osteoclasts to release calcium from bones.
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Underproduction of growth hormone during the growing years produces ______.
- A. myxedema.
- B. gigantism.
- C. pituitary dwarfism.
- D. acromegaly.
Correct Answer: C
Rationale: The correct answer is C: pituitary dwarfism. Growth hormone deficiency during growing years results in pituitary dwarfism due to stunted growth. Myxedema (choice A) is associated with hypothyroidism, not growth hormone deficiency. Gigantism (choice B) occurs due to excessive growth hormone production in childhood. Acromegaly (choice D) is caused by excess growth hormone in adulthood, not during the growing years. Thus, choice C is the most appropriate based on the impact of growth hormone deficiency on growth during childhood.
Which of the following is NOT true of cortisol?
- A. It counteracts the inflammatory response.
- B. It promotes the breakdown of proteins to amino acids that the liver uses to convert to glucose.
- C. It promotes metabolism of fatty acids instead of glucose.
- D. It is a mineralocorticoid.
Correct Answer: D
Rationale: Correct Answer: D - It is a mineralocorticoid.
Rationale: Cortisol is a glucocorticoid, not a mineralocorticoid. Glucocorticoids like cortisol regulate glucose metabolism and counteract inflammation, supporting options A and B. Option C is also incorrect as cortisol promotes the metabolism of glucose over fatty acids.
Which of the following hormones is found within the hypophyseal-hypothalamic portal capillaries?
- A. Gonadotropins
- B. Releasing hormones
- C. Catecholamines
- D. Mineralocorticoids
Correct Answer: B
Rationale: The correct answer is B: Releasing hormones. Releasing hormones are produced in the hypothalamus and travel through the hypophyseal-hypothalamic portal capillaries to reach the anterior pituitary gland. This is where they stimulate the release of specific hormones. Gonadotropins (A) are produced by the anterior pituitary gland, not found within the portal capillaries. Catecholamines (C) are produced by the adrenal glands, not within the portal capillaries. Mineralocorticoids (D) are steroid hormones produced by the adrenal cortex, not found within the portal capillaries.
Saliva contains the enzyme salivary amylase. Which food type does salivary amylase begin to break down?
- A. Proteins
- B. Starches
- C. Roughage
- D. Fats
Correct Answer: B
Rationale: Salivary amylase breaks down starches into simple sugars like maltose. Starch is a complex carbohydrate found in foods like bread, pasta, and rice. When you chew food, salivary amylase in saliva starts the digestion process by breaking down starch molecules. Proteins are broken down by stomach enzymes, roughage (fiber) is not digested by enzymes in the mouth, and fats are primarily digested in the small intestine by pancreatic lipase. Therefore, choice B, starches, is the correct answer as salivary amylase specifically targets this food type for initial breakdown.
Which of the following is NOT true of testosterone?
- A. growth of the penis and testes.
- B. brings about the male secondary sex characteristics.
- C. can cause baldness.
- D. controlled from the thyroid gland.
Correct Answer: D
Rationale: The correct answer is D because testosterone is not controlled by the thyroid gland. Testosterone is primarily produced in the testes and regulated by the hypothalamus and pituitary gland. The other choices (A, B, C) are all true of testosterone. Testosterone is responsible for the growth of the penis and testes (A), development of male secondary sex characteristics (B), and can potentially lead to baldness due to its effects on hair follicles (C). Thyroid gland primarily regulates metabolism and energy levels, not testosterone production.