Nokea
What is the density of the block and does it float or sink in the liquid?
- A. 0.50, floats
- B. 0.50, sinks
- C. 2.0, floats
- D. 2.0, sinks
Correct Answer: D
Rationale: The correct answer is D: 2.0, sinks. Density is calculated by mass/volume. If the density of the block is 2.0, it means it is denser than the liquid (density of water is around 1.0), so it will sink. If the density was 0.50, it would be less dense than the liquid and float, making choices A and C incorrect. Choice B is also incorrect as a block with a density of 0.50 would float.
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In its action in cells, aldosterone
- A. increases transport of ENaCs from the cytoplasm to the cell membrane
- B. does not act on the cell membrane
- C. binds to a receptor excluded from the nucleus
- D. may activate a heat shock protein
Correct Answer: A
Rationale: The correct answer is A because aldosterone increases the transport of epithelial sodium channels (ENaCs) from the cytoplasm to the cell membrane. This process leads to enhanced sodium reabsorption in the kidneys, promoting water retention and increasing blood pressure. Choices B and C are incorrect as aldosterone does act on the cell membrane and binds to a receptor located in the cytoplasm, which then translocates to the nucleus. Choice D is incorrect as aldosterone does not directly activate heat shock proteins.
Hypocalcemic tetany:
- A. is a consequence of a deficiency of calcitonin.
- B. is caused by a lack of TSH.
- C. is caused by osteoclastic activity.
- D. develops in response to a deficiency of parathyroid activity.
Correct Answer: D
Rationale: Step-by-step rationale:
1. Hypocalcemic tetany results from low blood calcium levels.
2. Parathyroid hormone (PTH) regulates calcium levels by increasing calcium release from bones and reabsorption in the kidneys.
3. A deficiency in parathyroid activity leads to decreased calcium levels, causing tetany.
4. Choice D is correct as it directly links hypocalcemic tetany to parathyroid dysfunction.
Summary:
A: Incorrect, calcitonin lowers blood calcium levels.
B: Incorrect, TSH regulates thyroid function, not calcium levels.
C: Incorrect, osteoclasts break down bone tissue but are not directly related to hypocalcemic tetany.
The following sympathomimetic drug is a catecholamine:
- A. Ephedrine
- B. Phenylephrine
- C. Phentolamine
- D. Isoprenaline
Correct Answer: D
Rationale: Step-by-step rationale for why D (Isoprenaline) is the correct answer:
1. Isoprenaline is a catecholamine because it has a catechol structure, which consists of a benzene ring with two hydroxyl groups.
2. Catecholamines are a class of neurotransmitters that include dopamine, norepinephrine, and epinephrine.
3. Isoprenaline acts as a non-selective beta-adrenergic agonist, stimulating both beta-1 and beta-2 adrenergic receptors.
4. Its pharmacological effects include increased heart rate, bronchodilation, and vasodilation.
Summary of why other choices are incorrect:
A. Ephedrine is a sympathomimetic drug but is not a catecholamine as it lacks the catechol structure.
B. Phenylephrine is a sympathomimetic drug that acts as an alpha-adrenergic agonist,
Which of the following structures connects the hypothalamus and the adenohypophysis?
- A. Islets of Langerhans
- B. Portal capillaries
- C. Corpus callosum
- D. Medulla oblongata
Correct Answer: B
Rationale: The correct answer is B: Portal capillaries. The hypothalamus and adenohypophysis are connected by a system of blood vessels called the hypothalamic-pituitary portal system, which includes portal capillaries. These capillaries carry releasing and inhibiting hormones from the hypothalamus to the adenohypophysis to regulate the secretion of pituitary hormones. The other choices are incorrect because:
A: Islets of Langerhans are clusters of cells in the pancreas involved in insulin and glucagon production, not connected to the hypothalamus or adenohypophysis.
C: The corpus callosum is a structure that connects the two cerebral hemispheres and is not related to the hypothalamus or adenohypophysis.
D: The medulla oblongata is part of the brainstem responsible for autonomic functions and is not involved in connecting the hypothalamus and adenohypophysis.
Which part of pancreas lies near the hilum of the spleen?
- A. Head
- B. Neck
- C. Body
- D. Tail
Correct Answer: D
Rationale: Step 1: The pancreas is an elongated organ located behind the stomach.
Step 2: The tail of the pancreas is the left end of the organ and is closest to the hilum of the spleen.
Step 3: The spleen and the tail of the pancreas are adjacent to each other in the upper left quadrant of the abdomen.
Step 4: Therefore, the correct answer is D: Tail.
Summary:
- A: Head is incorrect as it is the right end of the pancreas, farther away from the spleen.
- B: Neck is incorrect as it is the narrow portion between the head and body, not near the spleen.
- C: Body is incorrect as it is the central and longest part of the pancreas, not near the spleen.
- D: Tail is correct as it is the left end of the pancreas, nearest to the hilum of the spleen.