The point of junction of the muscle to the bone that moves is called the ___________________.

Correct Answer: A

Rationale: The correct answer is A: Insertion. The point of junction of the muscle to the bone that moves is called the insertion because this is where the muscle attaches to the bone that it acts upon. The insertion is typically located distally in relation to the origin of the muscle. The origin, choice B, refers to the point of attachment of the muscle to the stationary bone. Choices C and D, Sheath and Fascia, are incorrect as they do not specifically refer to the point of junction of the muscle to the bone that moves.

Correct Answer: B

Rationale: B: They are nerve cells. Rationale: Muller's cells are a type of glial cell in the retina, not nerve cells. They provide structural support and play a role in maintaining the retinal environment. Other choices are true: A) They form limiting membranes, C) They have long processes, and D) Their nuclei are in the inner nuclear layer.

Correct Answer: B

Rationale: The correct answer is B: epididymis. Sperm maturation occurs in the epididymis, a coiled tube located on the posterior surface of the testes. Here, sperm undergo the process of capacitation, gaining the ability to fertilize an egg. The seminiferous tubules (choice A) are responsible for sperm production, not maturation. The vas deferens (choice C) is a duct that carries mature sperm from the epididymis to the urethra, and the urethra (choice D) is a passage for both urine and sperm but not the site of sperm maturation.

Correct Answer: B

Rationale: The correct answer is B: Inhibin. Inhibin is a hormone secreted by the testes in response to high levels of sperm production. Inhibin acts as a negative feedback signal to the pituitary gland, inhibiting the production of follicle-stimulating hormone (FSH). This helps to regulate spermatogenesis by preventing excessive FSH stimulation. A: Testosterone is not the negative feedback signal for inhibiting FSH production. While testosterone does play a role in regulating spermatogenesis, it does not directly inhibit pituitary FSH production. C: Estrogen is not involved in the negative feedback control system of spermatogenesis. Estrogen is more closely associated with the female reproductive system. D: Luteinizing hormone is not the negative feedback signal for inhibiting FSH production. LH is involved in the regulation of testosterone production, not FSH.

Correct Answer: A

Rationale: The correct answer is A: She has been receiving hormone replacement therapy with estrogen and progesterone since she completed menopause. Hormone replacement therapy suppresses the release of FSH by providing exogenous hormones, thereby reducing the body's need to produce FSH. This explains the low levels of FSH in her blood despite being postmenopausal. Explanation for why the other choices are incorrect: B: Her adrenal glands continue to produce estrogen - Adrenal glands do produce small amounts of estrogen, but not in sufficient quantities to significantly impact FSH levels. C: Her ovaries continue to secrete estrogen - Ovaries cease estrogen production after menopause, so this would not explain the low FSH levels. D: She took birth control pills for 20 years before menopause - Birth control pills do not directly impact FSH levels in postmenopausal women.