Nokea
The hypothalamus is functionally and anatomically connected to the posterior pituitary lobe by a bridge of .
- A. blood vessels
- B. nerve axons
- C. cartilage
- D. bone
Correct Answer: B
Rationale: The correct answer is B: nerve axons. The hypothalamus communicates with the posterior pituitary lobe through nerve axons that form the hypothalamic-pituitary tract. This pathway allows for the release of hormones such as oxytocin and vasopressin directly into the bloodstream. Blood vessels (choice A) are not directly responsible for the connection between the hypothalamus and the posterior pituitary. Cartilage (choice C) and bone (choice D) do not play a role in this connection and are not anatomically linked to the hypothalamus and posterior pituitary.
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Which statement explains why elements in the same group of the Periodic Table have similar chemical properties?
- A. They have different numbers of protons.
- B. They have the same number of neutrons.
- C. They have the same number of electron shells.
- D. They have the same number of outer-shell electrons.
Correct Answer: D
Rationale: Correct Answer: D
Rationale:
1. Elements in the same group have similar outer electron configurations.
2. Outer-shell electrons determine chemical properties.
3. Having the same number of outer-shell electrons leads to similar chemical behaviors.
4. This is due to similar valence electron interactions in chemical reactions.
Summary:
A: Incorrect. Protons do not determine chemical properties in the same group.
B: Incorrect. Neutrons do not affect chemical properties in the same group.
C: Incorrect. Having the same number of electron shells does not guarantee similar chemical properties.
The house officer considers prescribing nadolol for a 53-year-old patient. Which of the following preexisting conditions (co-morbidities) would most likely contraindicate safe use of this drug?
- A. Angina pectoris, chronic-stable (effort-induced)
- B. Asthma
- C. Essential hypertension
- D. Heart failure, mild
Correct Answer: B
Rationale: The correct answer is B: Asthma. Nadolol is a non-selective beta-blocker, which can lead to bronchoconstriction and worsen asthma symptoms due to its effect on beta-2 receptors in the lungs. This can be dangerous for patients with asthma as it can exacerbate respiratory distress. Choices A, C, and D are not contraindications for nadolol as it can actually be beneficial in these conditions by reducing heart rate and blood pressure.
PTH:
- A. lowers plasma calcium.
- B. stimulates osteoclastic activity.
- C. is an iodine-containing hormone.
- D. stimulates osteoblastic activity and causes blood calcium levels to increase.
Correct Answer: B
Rationale: The correct answer is B: stimulates osteoclastic activity. Parathyroid hormone (PTH) acts on bones to stimulate osteoclasts, which are responsible for breaking down bone tissue to release calcium into the bloodstream. This process helps increase blood calcium levels. Choices A, C, and D are incorrect because PTH actually increases plasma calcium levels, is not an iodine-containing hormone, and does not stimulate osteoblastic activity.
The endocrine gland responsible for the body's circadian rhythm is the:
- A. Thymus gland.
- B. Pineal gland.
- C. Parathyroid gland.
- D. Pituitary gland.
Correct Answer: B
Rationale: The correct answer is B: Pineal gland. The pineal gland produces melatonin, a hormone that regulates the body's circadian rhythm, including sleep-wake cycles. This gland is sensitive to light and darkness, influencing the body's internal clock.
A: Thymus gland is responsible for immune function, not circadian rhythm.
C: Parathyroid gland regulates calcium levels in the body, not circadian rhythm.
D: Pituitary gland controls various other hormones but not specifically circadian rhythm.
The anterior pituitary gland:
- A. is called the neurohypophysis.
- B. releases ADH and oxytocin.
- C. secretes releasing hormones.
- D. is connected to the hypothalamus by the portal capillaries.
Correct Answer: D
Rationale: Step-by-step rationale:
1. The anterior pituitary gland is connected to the hypothalamus by the portal capillaries.
2. This connection allows for the transport of releasing hormones from the hypothalamus to the anterior pituitary.
3. Releasing hormones stimulate the anterior pituitary to release specific hormones.
4. This communication pathway is essential for regulating hormone production and maintaining homeostasis.
Summary of other choices:
A: Incorrect. The neurohypophysis refers to the posterior pituitary, not the anterior pituitary.
B: Incorrect. ADH and oxytocin are released from the posterior pituitary, not the anterior pituitary.
C: Incorrect. Releasing hormones are produced by the hypothalamus, not the anterior pituitary.