Nokea
Insulin, cortisol, thyroxine, and oxytocin:
- A. are hypothalamic-releasing hormones.
- B. are secreted by the adenohypophysis.
- C. increase blood glucose levels.
- D. are hormones.
Correct Answer: D
Rationale: Rationale:
1. Insulin, cortisol, thyroxine, and oxytocin are all hormones produced by various glands in the body.
2. Insulin is produced by the pancreas, cortisol by the adrenal glands, thyroxine by the thyroid gland, and oxytocin by the hypothalamus and released by the pituitary gland.
3. Each of these hormones plays a different role in the body, such as regulating blood glucose levels, metabolism, stress response, and reproductive functions.
4. Therefore, the correct answer is D: they are all hormones.
Summary:
A: Incorrect. Hypothalamic-releasing hormones are specific hormones that stimulate the release of other hormones from the pituitary gland.
B: Incorrect. Adenohypophysis secretes different hormones, not these specific ones.
C: Incorrect. Insulin, for example, decreases blood glucose levels, while cortisol increases blood glucose levels.
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Hyoscine is one of the most effective drugs for preventing motion sickness, but may cause photophobia or blurred vision. Which is the most similar prototype drug?
- A. A monoamine oxidase inhibitor
- B. Propranolol
- C. Atropine
- D. Bethanechol
Correct Answer: C
Rationale: Step 1: Hyoscine is an antimuscarinic drug used for motion sickness.
Step 2: Atropine is a similar prototype drug as it also belongs to the antimuscarinic class.
Step 3: Atropine, like hyoscine, can cause photophobia and blurred vision.
Step 4: Monoamine oxidase inhibitors (A) are not related to antimuscarinic drugs.
Step 5: Propranolol (B) is a beta-blocker and not an antimuscarinic drug.
Step 6: Bethanechol (D) is a muscarinic agonist, opposite in action to antimuscarinic drugs like hyoscine and atropine.
The action of gastrin includes all EXCEPT:
- A. stimulation of insulin secretion after a carbohydrate meal
- B. stimulation of gastric acid secretion
- C. stimulation of gastric motility
- D. contraction of gastro-oesophageal junction musculature
Correct Answer: A
Rationale: The correct answer is A because gastrin primarily stimulates gastric acid secretion and gastric motility, not insulin secretion. Gastrin is released in response to the presence of food in the stomach, leading to increased gastric acid production and motility to aid in digestion. Insulin secretion is mainly regulated by glucose levels in the blood and hormones like insulin and glucagon. Therefore, the stimulation of insulin secretion after a carbohydrate meal is not a direct action of gastrin. Choices B, C, and D are incorrect because they accurately describe the actions of gastrin in the digestive system.
Which of the following statements about the hormone glucagon is true?
- A. It is secreted by the beta cells in the islets of Langerhans
- B. It is secreted in response to a rise in blood glucose
- C. It promotes the breakdown of glycogen in the liver
- D. It promotes the synthesis of glycogen in the liver
Correct Answer: C
Rationale: The correct answer is C: Glucagon promotes the breakdown of glycogen in the liver. Glucagon is secreted by the alpha cells in the islets of Langerhans in response to low blood glucose levels. When released, glucagon stimulates the liver to break down glycogen into glucose through a process called glycogenolysis, thus increasing blood glucose levels. This helps maintain blood glucose homeostasis during fasting or low glucose conditions. Options A and B are incorrect because glucagon is secreted by alpha cells, not beta cells, and in response to low blood glucose, not high. Option D is incorrect as glucagon promotes glycogen breakdown, not synthesis.
Which is NOT produced by the citric acid cycle?
- A. NAD+
- B. CO2
- C. GTP
- D. FADH2
Correct Answer: A
Rationale: Step 1: NAD+ is a reactant in the citric acid cycle, not a product.
Step 2: NAD+ is reduced to NADH during the cycle.
Step 3: NAD+ is not directly produced as a final product in the cycle.
Step 4: Therefore, A: NAD+ is NOT produced by the citric acid cycle.
Summary: B: CO2 and D: FADH2 are produced in the cycle, while C: GTP is generated through substrate-level phosphorylation.
Complete the following sentence: Lipid-soluble hormones are…
- A. Constantly produced within the anterior pituitary gland and released into the blood stream
- B. Hydrophilic and are transported in an un-conjugated form in the blood
- C. Interact with intracellular receptors and evoke changes in gene expression
- D. Formed from amino acids
Correct Answer: C
Rationale: The correct answer is C because lipid-soluble hormones can freely diffuse through cell membranes to interact with intracellular receptors, leading to changes in gene expression. This mechanism is characteristic of lipid-soluble hormones, such as steroid hormones. Choice A is incorrect because lipid-soluble hormones are not constantly produced in the anterior pituitary gland. Choice B is incorrect as lipid-soluble hormones are hydrophobic, not hydrophilic, and are often transported bound to carrier proteins in the blood. Choice D is incorrect because lipid-soluble hormones are not formed from amino acids; rather, they are derived from cholesterol or similar compounds.