Nokea
The release of oxytocin is controlled by _____ feedback.
- A. negative
- B. neutral
- C. positive
Correct Answer: C
Rationale: The correct answer is C: positive feedback. Oxytocin release is triggered by the positive feedback mechanism. When oxytocin is released in response to a stimulus, it further stimulates the release of more oxytocin, intensifying the effect. This continuous loop enhances the initial response, leading to a cascade effect. Negative feedback (choice A) works to maintain homeostasis by counteracting the initial stimulus, which is not the case for oxytocin release. Neutral feedback (choice B) does not play a significant role in regulating hormone release. Choice D is incomplete and irrelevant.
You may also like to solve these questions
Which of the following descriptions best fits the drug phenylephrine?
- A. Blocks muscarinic receptors
- B. Stimulates α-adrenergic receptors, causing useful mucous membrane decongestion, or overall vasoconstriction and a rise of blood pressure
- C. Blocks β-adrenergic receptors
- D. Useful drug for managing hypertension
Correct Answer: B
Rationale: The correct answer is B because phenylephrine stimulates α-adrenergic receptors, leading to vasoconstriction and mucous membrane decongestion. This action helps relieve nasal congestion. Choice A is incorrect because phenylephrine does not block muscarinic receptors. Choice C is incorrect because phenylephrine does not block β-adrenergic receptors. Choice D is incorrect because phenylephrine is not typically used for managing hypertension.
The normal response to increased serum osmolality is the release of
- A. aldosterone from the adrenal cortex, which stimulates sodium excretion by the kidney.
- B. ADH from the posterior pituitary gland, which stimulates the kidney to reabsorb water.
- C. mineralocorticoids from the adrenal gland, which stimulate the kidney to excrete potassium.
- D. calcitonin from the thyroid gland, which increases bone resorption and decreases serum calcium levels.
Correct Answer: B
Rationale: ADH (antidiuretic hormone) is released to promote water reabsorption by the kidneys when serum osmolality increases.
Which of the following structures lies posterior to body of pancreas:
- A. IVC
- B. Portal vein
- C. Common bile duct
- D. Splenic vein
Correct Answer: D
Rationale: The correct answer is D: Splenic vein. The splenic vein lies posterior to the body of the pancreas. Step 1: Locate the pancreas in the abdominal cavity. Step 2: Identify the structures behind the body of the pancreas. Step 3: The splenic vein runs posterior to the body of the pancreas, making it the correct answer. Other choices are incorrect because A: IVC is located more inferiorly, B: Portal vein is located more superiorly, and C: Common bile duct is located more anteriorly to the body of the pancreas.
Regarding the flavoprotein – cytochrome system:
- A. cytochrome oxidase is the first step in the chain
- B. occurs within the endoplasmic reticulum
- C. substrates are pyruvate, water and oxygen and ATP
Correct Answer: C
Rationale: The correct answer is C because the substrates of the flavoprotein-cytochrome system are pyruvate, water, oxygen, and ATP. Pyruvate is oxidized to produce energy in the form of ATP, water is a byproduct of the electron transport chain, and oxygen is the final electron acceptor. Choices A and B are incorrect because cytochrome oxidase is not the first step in the chain, and the system does not occur within the endoplasmic reticulum. Choice D is incomplete.
Mineralocorticoid is to aldosterone as glucocorticoid is to ________.
- A. testosterone
- B. estrogen
- C. cortisol
- D. epinephrine
Correct Answer: C
Rationale: Mineralocorticoids regulate electrolyte and fluid balance, with aldosterone being the primary mineralocorticoid. Glucocorticoids regulate metabolism and immune response, with cortisol being the primary glucocorticoid. Therefore, the correct answer is C: cortisol. Testosterone (A) and estrogen (B) are sex hormones, not corticosteroids. Epinephrine (D) is a hormone produced by the adrenal medulla, not a corticosteroid.