Vasopressin is secreted by which nucleus of hypothalamus?
**Core Concept**
The hypothalamus is a crucial region in the brain that regulates various autonomic functions, including hormone secretion. Vasopressin, also known as antidiuretic hormone (ADH), is a hormone involved in water reabsorption in the kidneys and has a pressor effect on blood vessels.
**Why the Correct Answer is Right**
Vasopressin is secreted by the supraoptic nucleus (SON) and the paraventricular nucleus (PVN) of the hypothalamus. These nuclei contain neurons that synthesize and store vasopressin, which is then released into the bloodstream. The SON is primarily responsible for vasopressin secretion, while the PVN is involved in the regulation of other hormones, including oxytocin and corticotropin-releasing hormone.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify a nucleus of the hypothalamus involved in vasopressin secretion. The hypothalamus has many nuclei, but only the SON and PVN are responsible for vasopressin secretion.
**Option B:** This option is incorrect because the arcuate nucleus is involved in the regulation of gonadotropin-releasing hormone (GnRH) and growth hormone-releasing hormone (GHRH), but not vasopressin.
**Option C:** This option is incorrect because the dorsomedial nucleus is involved in the regulation of emotions and appetite, but not vasopressin secretion.
**Option D:** This option is incorrect because the lateral hypothalamus is involved in the regulation of hunger and thirst, but not vasopressin secretion.
**Clinical Pearl / High-Yield Fact**
The supraoptic nucleus and paraventricular nucleus are the primary sites of vasopressin synthesis in the hypothalamus. Damage to these nuclei can lead to central diabetes insipidus, a condition characterized by excessive thirst and polyuria.
**Correct Answer: C. Paraventricular nucleus (PVN) and Supraoptic nucleus (SON).**