If you drank a liter of water very quickly, the result would be
- A. increased secretion of oxytocin
- B. decreased secretion of antidiuretic hormone
- C. decreased secretion of oxytocin
- D. increased secretion of antidiuretic hormone
Correct Answer: B
Rationale: The correct answer is B: decreased secretion of antidiuretic hormone. When you drink a liter of water quickly, it leads to a sudden increase in blood volume and a decrease in blood osmolality. This triggers the body to reduce the secretion of antidiuretic hormone (ADH) to prevent excessive water retention and maintain proper fluid balance. ADH helps in water reabsorption in the kidneys, so decreased secretion allows for more water to be excreted through urine. The other choices are incorrect because drinking water rapidly would not directly affect oxytocin secretion.
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Each of the following types of receptors is correctly matched with the response resulting from its stimulation EXCEPT:
- A. Muscarinic receptors - decreased heart rate
- B. Nicotinic receptors - decreased gastric acid secretion
- C. Alpha adrenergic receptors - increased blood pressure
- D. Beta adrenergic receptors - bronchodilation
Correct Answer: B
Rationale: The correct answer is B. Nicotinic receptors are not associated with decreased gastric acid secretion, but rather with muscle contraction at neuromuscular junctions. A: Muscarinic receptors stimulation leads to decreased heart rate via parasympathetic activation. C: Activation of alpha adrenergic receptors causes vasoconstriction and increased blood pressure. D: Stimulation of beta adrenergic receptors results in bronchodilation and increased heart rate. Therefore, choice B is the exception as it does not match the typical response of nicotinic receptors.
Adrenaline is NOT given orally because:
- A. It is inactivated in the gut mucosa
- B. Local vasoconstriction inhibits absorption
- C. It is rapidly inactivated in circulation
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D: All of the above. Adrenaline is not given orally because: A) It is inactivated in the gut mucosa due to enzymatic breakdown, B) Local vasoconstriction inhibits absorption into the bloodstream, and C) It is rapidly inactivated in circulation by enzymes like catechol-O-methyltransferase and monoamine oxidase. Therefore, administering adrenaline orally would result in poor absorption and rapid degradation, making it ineffective.
Cells that respond to a particular hormone are called
- A. receptor cells.
- B. sensor cells.
- C. secretory cells.
- D. target cells.
Correct Answer: D
Rationale: The correct answer is D: target cells. Target cells are specific cells that have receptors for a particular hormone, allowing them to respond to the hormone's signal. These cells are the intended recipients of the hormone's message and carry out the appropriate physiological response. Receptor cells (A) are more general and can refer to any cell with receptors, not necessarily for hormones. Sensor cells (B) detect stimuli but may not necessarily respond to hormones. Secretory cells (C) release hormones rather than respond to them.
In the pancreas, which are the cells that secrete insulin, decrease the blood levels of glucose.
- A. delta.
- B. alpha.
- C. beta.
- D. beta.
Correct Answer: C
Rationale: The correct answer is C: beta cells. Beta cells in the pancreas secrete insulin, which helps decrease blood glucose levels by facilitating the uptake of glucose into cells for energy production. Delta cells (choice A) secrete somatostatin, which inhibits insulin and glucagon secretion. Alpha cells (choice B) secrete glucagon, which increases blood glucose levels. Choice D is a duplicate of choice C. Therefore, the correct answer is C as beta cells play a crucial role in regulating blood glucose levels through insulin secretion.
How do hormones differ from neurotransmitters?
- A. Hormones travel through the synaptic cleft while neurotransmitters travel through the bloodstream.
- B. Hormones act on receptors while neurotransmitters do not.
- C. Hormones use speedy electrical impulses, while neurotransmitters take several seconds from the gland to the target tissue.
- D. Hormones travel through the bloodstream while neurotransmitters travel across the synaptic cleft between neurons.
Correct Answer: D
Rationale: The correct answer is D. Hormones travel through the bloodstream while neurotransmitters travel across the synaptic cleft between neurons. Hormones are secreted by endocrine glands into the bloodstream to target distant tissues, while neurotransmitters are released by neurons into the synaptic cleft to transmit signals locally between neurons. Choice A is incorrect as hormones do not travel through the synaptic cleft, and neurotransmitters do not travel through the bloodstream. Choice B is incorrect as both hormones and neurotransmitters act on specific receptors. Choice C is incorrect as hormones do not use electrical impulses; instead, they travel through the bloodstream.