Nokea
ACTH, TSH, and gonadotropins are:
- A. hypothalamic-releasing hormones.
- B. secreted by the neurohypophysis.
- C. “aimed at†the adrenal cortex.
- D. tropic hormones.
Correct Answer: D
Rationale: Step 1: ACTH, TSH, and gonadotropins are hormones that stimulate the secretion of other hormones.
Step 2: These hormones target specific endocrine glands, such as the adrenal cortex.
Step 3: Since these hormones stimulate the secretion of other hormones and target specific glands, they are classified as tropic hormones.
Step 4: Thus, the correct answer is D: tropic hormones.
Summary: A is incorrect as they are not hypothalamic-releasing hormones. B is incorrect as they are not secreted by the neurohypophysis. C is incorrect as they are not specifically aimed at the adrenal cortex.
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The Action of Parathormone in the Human Body
- A. Decreases blood sodium level
- B. Increases blood sodium level
- C. Decreases blood calcium level
- D. Increases blood calcium level
Correct Answer: D
Rationale: The correct answer is D: Increases blood calcium level. Parathormone is released by the parathyroid glands in response to low blood calcium levels. It acts to increase blood calcium levels by stimulating the release of calcium from bones, increasing calcium absorption in the intestines, and promoting calcium reabsorption in the kidneys. This helps to maintain proper calcium levels in the body. Choices A, B, and C are incorrect because parathormone does not have any direct effect on blood sodium levels and actually works to increase, not decrease, blood calcium levels.
When an action potential reaches the axon terminal, what happens next?
- A. The muscle fiber contracts
- B. Acetylcholinesterase breaks down acetylcholine in the synaptic cleft
- C. Endosomes containing neurotransmitter fuse to cell membrane, and release neurotransmitter into the synaptic cleft
- D. Sodium channels open at the motor end plate, moving the cell membrane closer to threshold
Correct Answer: c
Rationale: The correct answer is C because when an action potential reaches the axon terminal, endosomes containing neurotransmitters fuse with the cell membrane and release neurotransmitter into the synaptic cleft. This process is known as exocytosis. This neurotransmitter then binds to receptors on the postsynaptic neuron, initiating a new action potential.
Choice A is incorrect because the muscle fiber contraction is initiated by the binding of the neurotransmitter to receptors on the muscle cell, not directly by the action potential reaching the axon terminal.
Choice B is incorrect because acetylcholinesterase breaks down acetylcholine in the synaptic cleft after it has already been released and has completed its role in transmitting the signal.
Choice D is incorrect because sodium channels opening at the motor end plate is part of the process of muscle cell depolarization and contraction, not directly related to the release of neurotransmitter at the axon terminal.
Hormone release stops when the stimulus that triggered it – like thirst or high blood sugar is satisfied or corrected. This is called:
- A. positive feedback system
- B. negative feedback system
- C. lock and key system
- D. solar system
Correct Answer: B
Rationale: The correct answer is B: negative feedback system. In a negative feedback system, the body's response to a stimulus works to counteract the initial stimulus, bringing the body back to its set point. In the context of the question, hormone release stops when the stimulus is satisfied, which is characteristic of a negative feedback system. A: Positive feedback system amplifies the initial stimulus rather than counteracting it. C: Lock and key system refers to how enzymes bind to specific substrates, not related to hormone regulation. D: Solar system is unrelated to physiological processes.
The actions of gastrin include all but:
- A. insulin secretion in response to a carbohydrate meal
- B. a trophic effect on colonic mucosa
- C. a trophic effect on gastric mucosa
- D. pepsin secretion
Correct Answer: A
Rationale: The correct answer is A because gastrin primarily stimulates gastric acid secretion and gastric mucosal growth but not insulin secretion. Gastrin acts on parietal cells to stimulate acid production and chief cells to release pepsinogen. Choice B and C are incorrect as gastrin does have a trophic effect on colonic and gastric mucosa, respectively. Choice D is also incorrect as gastrin stimulates pepsin secretion.
Individualized nutrition therapy for patients using conventional, fixed insulin regimens should include teaching the patient to
- A. eat regular meals at regular times.
- B. restrict calories to promote moderate weight loss.
- C. eliminate sucrose and other simple sugars from the diet.
- D. limit saturated fat intake to 30% of dietary calorie intake.
Correct Answer: A
Rationale: Patients with fixed insulin regimens should eat regular meals to match insulin action and prevent hypoglycemia.