Endocrine glands are typically:

Correct Answer: B

Rationale: The correct answer is B: ductless. Endocrine glands release hormones directly into the bloodstream without the use of ducts. This allows hormones to reach target organs throughout the body. Choice A (vascular) is incorrect because it refers to the presence of blood vessels, which is common in all glands, not just endocrine glands. Choice C (square) is irrelevant as the shape of glands does not determine their function. Choice D (autonomous) is incorrect as it does not accurately describe endocrine glands; while they function independently, the term "autonomous" does not specifically apply to them.

Correct Answer: A

Rationale: The correct answer is A because ADH secretion is increased during stress to retain water in the body. This response helps maintain blood pressure and prevent dehydration under stressful conditions. Choice B is incorrect because ADH secretion is actually increased during hemorrhage to conserve water. Choice C is incorrect because increased blood osmolality triggers ADH secretion to retain water. Choice D is incorrect because alcohol inhibits ADH secretion, leading to increased urine production.

Correct Answer: D

Rationale: The correct answer is D because the anterior pituitary is regulated by hypothalamic neuropeptides. The hypothalamus secretes releasing and inhibiting hormones that control the anterior pituitary's hormone release. This close interaction between the hypothalamus and the anterior pituitary is known as the hypothalamic-pituitary axis. A is incorrect because the anterior pituitary is not neural tissue, it is an endocrine gland. B is incorrect because the anterior pituitary synthesizes and secretes peptide hormones, not steroid hormones. C is incorrect because the anterior pituitary is located at the base of the brain, not above the kidney.

Correct Answer: D

Rationale: The correct answer is D because oxytocin and anti-diuretic hormone are synthesized in the hypothalamus and stored in the posterior pituitary gland before being released into the bloodstream. This process is essential for regulating various physiological functions. Choices A and C are incorrect as oxytocin and anti-diuretic hormone are not complex steroids and are not released from the anterior pituitary. Choice B is also incorrect because while these hormones are indeed synthesized in the posterior pituitary, they are stored in the posterior pituitary before their release.

Correct Answer: A

Rationale: Step-by-step rationale for why answer A is correct: 1. Oxytocin is synthesized in the hypothalamus and released into the bloodstream. 2. In the plasma, oxytocin binds to neurophysin, a carrier protein. 3. This binding helps stabilize oxytocin and regulate its release and distribution. 4. Therefore, choice A is correct as oxytocin is bound to neurophysin in plasma. Summary: - Choice B is incorrect as oxytocin stimulates milk ejection, not inhibits milk production. - Choice C is incorrect as oxytocin promotes myometrial contraction during labor. - Choice D is incorrect as oxytocin can enhance sperm motility, not inhibit it.