Which of these hormones is made by the posterior pituitary?

Correct Answer: D

Rationale: The correct answer is D: ADH (Antidiuretic Hormone). ADH is produced by the posterior pituitary gland and regulates water balance in the body by acting on the kidneys to reduce urine output. FSH, LH, and ACTH are produced by the anterior pituitary gland and have different functions related to reproductive health and stress response. The key to this question is knowing the specific hormones produced by the posterior pituitary gland, making D the correct choice.

Correct Answer: B

Rationale: The correct answer is B: Oxytocin. Neurones secrete oxytocin, a hormone involved in social bonding, childbirth, and lactation. Neurones release oxytocin from the hypothalamus into the bloodstream. Insulin is secreted by pancreatic cells, not neurones. Thyroid stimulating hormone is produced by the pituitary gland, and cortisol is released by the adrenal glands. Therefore, the correct answer is oxytocin as it is the hormone secreted by neurones.

Correct Answer: A

Rationale: The correct answer is A: Pineal gland. Melatonin is a hormone that regulates sleep-wake cycles and is primarily secreted by the pineal gland located in the brain. The pineal gland responds to darkness by releasing melatonin, which helps to induce sleep. The other choices, B: Thyroid, C: Thymus, and D: Adrenal, do not secrete melatonin. The thyroid gland produces hormones that regulate metabolism, the thymus gland is involved in immune function, and the adrenal glands secrete hormones like cortisol and adrenaline. Therefore, the pineal gland is the correct answer for melatonin secretion.

Correct Answer: A

Rationale: The correct answer is A because endocrine glands release hormones directly into the bloodstream to reach target organs and regulate various physiological processes. This allows for systemic effects on the body. Choices B and C are incorrect as hormones are not released directly into tissues or skin. Choice D is also incorrect as endocrine glands release hormones directly into the bloodstream, not through ducts.

Correct Answer: A

Rationale: Rationale for Choice A: 1. The hypothalamus produces oxytocin and antidiuretic hormone (ADH). 2. These hormones are transported via the hypothalamic-pituitary portal system to the posterior pituitary for storage. 3. When needed, the posterior pituitary releases these hormones into the bloodstream. 4. Oxytocin is involved in labor and milk ejection, while ADH regulates water balance by increasing water reabsorption in the kidneys. Summary of other Choices: B. Incorrect - ADH, when released, causes urine volume to decrease and blood volume to increase by increasing water reabsorption. C. Incorrect - Luteinizing hormone triggers ovulation and stimulates progesterone production but is released by the anterior pituitary, not the hypothalamus. D. Incorrect - Hyposecretion of FSH or LH can lead to infertility, not necessarily sterility, and the effects differ between males and females.