The neurohypophysis or posterior lobe of the pituitary gland is not a true endocrine gland because ________.

Correct Answer: D

Rationale: The correct answer is D because the neurohypophysis stores hormones produced by the hypothalamus for release into the bloodstream. The neurohypophysis does not produce its own hormones but acts as a storage and release site. A is incorrect as the neurohypophysis does play a role in hormonal release through the release of hormones produced by the hypothalamus. B is incorrect as the neurohypophysis remains functional in adults. C is incorrect as the neurohypophysis does function as an endocrine tissue by releasing hormones into the bloodstream.

Correct Answer: C

Rationale: Step 1: Follicle-stimulating hormone (FSH) is essential for sperm production in males. Step 2: FSH is produced in the anterior pituitary gland. Step 3: In males, FSH stimulates the Sertoli cells in the testes to support sperm production. Step 4: Therefore, if a man is not synthesizing enough FSH, it can lead to reduced sperm production and fertility issues. Summary: A: Incorrect - FSH is synthesized by males in the anterior pituitary gland, not just females for estrogen secretion. B: Incorrect - Hormones produced in the adenohypophysis, like FSH, play a crucial role in fertility. D: Incorrect - Progesterone does not inhibit the synthesis of FSH; it is involved in the female reproductive system, not male fertility.

Correct Answer: A

Rationale: The correct answer is A: humoral. Humoral regulation refers to the control of physiological processes by substances in the blood, such as hormones. In this case, the production and release of hormones in response to a chemical like calcium is an example of humoral mechanism. This choice is correct because it specifically involves the blood-borne substances affecting hormone production. Choices B, C, and D are incorrect because neural regulation (B) involves the nervous system controlling physiological processes, sensory regulation (C) refers to sensory input influencing responses, and hormonal regulation (D) involves feedback loops within the endocrine system, not directly related to blood-borne substances like calcium.

Correct Answer: C

Rationale: The correct answer is C: diabetes insipidus. The inability to produce ADH (antidiuretic hormone) results in diabetes insipidus, characterized by excessive thirst and urination. ADH plays a crucial role in regulating water retention by the kidneys. Without ADH, the kidneys are unable to concentrate urine, leading to increased urine output and dehydration. A: Diabetes mellitus is not caused by the inability to produce ADH. It is a condition characterized by high blood sugar levels due to insufficient insulin production or ineffective use of insulin. B: Uterine contractions are not related to the production of ADH. Uterine contractions are primarily controlled by hormones such as oxytocin during labor. D: Decreased urine volume is the opposite of what occurs in diabetes insipidus. In this condition, there is an increase in urine volume due to the inability to concentrate urine.

Correct Answer: B

Rationale: Calcitonin is the correct answer because it is released from the thyroid gland in response to high blood calcium levels to deposit the excess calcium into the bones, decreasing blood calcium levels. Parathyroid hormone (A) works in the opposite way, increasing blood calcium levels by releasing calcium from bones. Oxytocin (C) is a hormone involved in labor and breastfeeding, not calcium regulation. Glucagon (D) is released from the pancreas to increase blood glucose levels, not calcium levels. Therefore, calcitonin is the most suitable choice for regulating high blood calcium levels by promoting calcium deposition in the bones.