Nokea
PTH:
- A. lowers plasma calcium.
- B. stimulates osteoclastic activity.
- C. is an iodine-containing hormone.
- D. stimulates osteoblastic activity and causes blood calcium levels to increase.
Correct Answer: B
Rationale: The correct answer is B: stimulates osteoclastic activity. Parathyroid hormone (PTH) acts on bones to stimulate osteoclasts, which are responsible for breaking down bone tissue to release calcium into the bloodstream. This process helps increase blood calcium levels. Choices A, C, and D are incorrect because PTH actually increases plasma calcium levels, is not an iodine-containing hormone, and does not stimulate osteoblastic activity.
You may also like to solve these questions
Which conditions would give the results shown in diagrams X and Y?
- A. carbon dioxide, 25°C, oxygen, 25°C
- B. carbon dioxide, 2°C, oxygen, 2°C
- C. oxygen, 25°C, carbon dioxide, 25°C
- D. oxygen, 2°C, carbon dioxide, 2°C
Correct Answer: C
Rationale: The correct answer is C because diagram X shows an increase in oxygen concentration over time, which indicates photosynthesis occurring. In photosynthesis, plants take in carbon dioxide and release oxygen. Therefore, the conditions of oxygen at 25°C and carbon dioxide at 25°C would support this process. Choices A, B, and D have incorrect combinations of temperature and gases that would not result in the observed increase in oxygen concentration in diagram X.
When blood calcium levels are high, ____ is released from the thyroid gland to deposit the excess calcium into the bones.
- A. parathyroid hormone
- B. calcitonin
- C. oxytocin
- D. glucagon
Correct Answer: B
Rationale: Calcitonin is the correct answer because it is released from the thyroid gland in response to high blood calcium levels to deposit the excess calcium into the bones, decreasing blood calcium levels. Parathyroid hormone (A) works in the opposite way, increasing blood calcium levels by releasing calcium from bones. Oxytocin (C) is a hormone involved in labor and breastfeeding, not calcium regulation. Glucagon (D) is released from the pancreas to increase blood glucose levels, not calcium levels. Therefore, calcitonin is the most suitable choice for regulating high blood calcium levels by promoting calcium deposition in the bones.
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.
Peptide hormones _______________.
- A. are hydrophilic
- B. cannot enter the target cell
- C. bind to a receptor on the cell surface
- D. all of these
Correct Answer: D
Rationale: The correct answer is D because peptide hormones are hydrophilic molecules that cannot pass through the cell membrane, so they bind to receptors on the cell surface to initiate signaling pathways within the cell. Therefore, they are unable to enter the target cell like lipid-soluble hormones do. By binding to specific receptors on the cell surface, peptide hormones trigger a series of events that ultimately lead to a cellular response. Therefore, all of the given statements are true, making D the correct choice.
Which of the following produced only by large amounts of glucocorticoids?
- A. Normal responsiveness of fat depots to norepinephrine
- B. Maintenance of normal vascular reactivity
- C. Increased excretion of a water load
- D. Inhibition of the inflammatory response
Correct Answer: D
Rationale: The correct answer is D because glucocorticoids inhibit the inflammatory response by suppressing the immune system. Glucocorticoids reduce inflammation by blocking the production of inflammatory substances like prostaglandins and cytokines. This effect is only observed in large amounts of glucocorticoids. Choices A, B, and C are not produced exclusively by large amounts of glucocorticoids. Normal responsiveness of fat depots to norepinephrine and maintenance of normal vascular reactivity are not directly related to glucocorticoids in large amounts. Increased excretion of a water load is more influenced by other factors such as hydration status and renal function.