Nokea
This cone-shaped gland is located in the head and is called the “biological clock.â€
- A. Posterior pituitary
- B. Hypothalamus
- C. Pineal
- D. Thymus
Correct Answer: C
Rationale: The correct answer is C: Pineal gland. The pineal gland is located in the brain and is often referred to as the "biological clock" due to its role in regulating the sleep-wake cycle through the secretion of melatonin. The posterior pituitary (choice A) is responsible for releasing hormones produced by the hypothalamus, not related to the circadian rhythm. The hypothalamus (choice B) is involved in regulating various physiological processes but is not directly associated with the circadian rhythm. The thymus (choice D) plays a role in the immune system, not in regulating the biological clock. Thus, the pineal gland is the correct answer as it specifically controls the circadian rhythm.
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The target organs of ADH are the:
- A. adrenal cortex and liver
- B. kidney and blood vessels
- C. liver and kidney
- D. pituitary and thyroid glands
Correct Answer: B
Rationale: The correct answer is B: kidney and blood vessels. ADH, or antidiuretic hormone, acts on the kidney to regulate water reabsorption and maintain fluid balance in the body. It also acts on blood vessels to regulate blood pressure. The other choices are incorrect because ADH does not target the adrenal cortex, liver, pituitary gland, or thyroid gland specifically for its primary functions. ADH primarily acts on the kidney and blood vessels to regulate water balance and blood pressure in the body.
This is the Most Abundant Hormone Produced by the Anterior Pituitary
- A. LH
- B. TSH
- C. ACTH
- D. GH
Correct Answer: D
Rationale: The correct answer is D: GH (Growth Hormone). GH is the most abundant hormone produced by the anterior pituitary gland. It plays a crucial role in regulating growth, metabolism, and cell repair. LH, TSH, and ACTH are also hormones produced by the anterior pituitary, but they are not as abundant as GH and do not have the same wide-ranging effects on the body. LH is involved in reproductive functions, TSH regulates thyroid function, and ACTH stimulates the adrenal glands. Therefore, based on the function and abundance of hormones produced by the anterior pituitary, GH is the correct answer.
Which is not Na+ dependent for absorption?
- A. thiamin
- B. riboflavin
- C. niacin
- D. folate
Correct Answer: D
Rationale: The correct answer is D: folate. Folate absorption is not Na+ dependent as it is primarily absorbed in the small intestine through a carrier-mediated process that is independent of sodium. Thiamin, riboflavin, and niacin absorption, on the other hand, are Na+ dependent processes that rely on sodium co-transporters for uptake in the small intestine. Thiamin is absorbed through a sodium-dependent active transport system, riboflavin requires a sodium-dependent carrier protein for absorption, and niacin absorption involves a sodium-dependent transporter in the small intestine. Therefore, folate is the only option that is not Na+ dependent for absorption.
What is the mass of hydrogen chloride that reacts with 5.1 g of ammonia?
- A. 3.65g
- B. 10.95g
- C. 7.05g
- D. 21.15g
Correct Answer: B
Rationale: To find the mass of hydrogen chloride that reacts with 5.1g of ammonia, we need to use the stoichiometry of the balanced chemical equation. The balanced equation for the reaction between ammonia (NH3) and hydrogen chloride (HCl) is:
NH3 + HCl → NH4Cl
From the equation, we can see that 1 mole of NH3 reacts with 1 mole of HCl to form 1 mole of NH4Cl. Therefore, the molar ratio of NH3 to HCl is 1:1.
First, we need to convert the given mass of ammonia (5.1g) to moles using the molar mass of ammonia (17g/mol):
5.1g NH3 * (1 mol NH3 / 17g NH3) = 0.3 mol NH3
Since the molar ratio of NH3 to HCl is 1:1, the moles of HCl that react with
A morbidly obese person visits the local bariatric (weight loss) clinic seeking a pill that will help shed weight. The physician prescribes dextroamphetamine. In addition to causing its expected centrally mediated anorexigenic (appetite-suppressant) effects, it causes a host of peripheral adrenergic effects that, for some patients, can prove fatal. The main mechanism by which dextroamphetamine or amphetamines in general, cause their peripheral autonomic effects is
- A. Activates MAO
- B. Blocks NE reuptake via the amine pump/transporter
- C. Displaces, releases, intraneuronal NE
- D. Enhances NE synthesis, leading to massive neurotransmitter overproduction
Correct Answer: C
Rationale: Rationale for Correct Answer (C): Dextroamphetamine causes peripheral adrenergic effects by displacing, releasing, intraneuronal NE. Amphetamines disrupt the storage and release of NE from intraneuronal vesicles, leading to an increase in synaptic NE levels. This excess NE can stimulate adrenergic receptors in the periphery, causing adverse effects like hypertension, tachycardia, and potentially fatal outcomes.
Summary of Incorrect Choices:
A: Activating MAO would increase NE breakdown, not cause peripheral adrenergic effects.
B: Blocking NE reuptake would increase NE levels in the synapse, not intraneuronally, leading to central effects.
D: Enhancing NE synthesis would not directly lead to peripheral adrenergic effects, as it would require release and action at the synapse.