The sympathetic nervous system is responsible for regulating the body's "fight-or-flight" response. Physiological changes produced by the sympathetic nervous system include accelerated heartbeat, dilated bronchi and pupils, glucose breakdown, and inhibited digestion. As a result, when the sympathetic nervous system is active, digestion and its associated involuntary contractions are inhibited—not stimulated.

"Dilated pupils, accelerated heart rate, relaxed bladder" is the correct answer here because it is the only choice is entirely comprised of sympathetic nervous system actions. Some red herrings in the other answers is the fact that constricted pupils is a parasympathetic action, as is stimulation of the salivary gland.

The sympathetic nervous system is one branch of the autonomic nervous system in the body. The autonomic nervous system is not under conscious control. The sympathetic system is responsible for our "fight or flight" response. An increase in heart rate when presented with the dangers of being around a bear is due to the sympathetic nervous system. The increase in heart rate is your body's way of increasing blood supply to the body to help you escape ("flight") from the bear and return to safety.

Growth-hormone-releasing hormone (GHRH) causes release of growth hormone (GH) from the anterior pituitary.

The posterior pituitary is responsible for antidiuretic hormone (ADH) and oxytocin release. The thyroid releases thyroid hormones (T3 and T4), which control metabolic rates. The pancreas releases glucagon and insulin to control blood sugar levels.

The hypothalamus releases hormones that control the release of hormones from the anterior pituitary, which in turn controls the release of hormones from other endocrine glands. The anterior pituitary is also controlled by several negative feedback systems based on hormones released throughout the body and their effects.

Gonadotropin-releasing hormone (GnRH), released from the hypothalamus, is responsible for regulating follicle-stimulating hormone and luteinizing hormone release. Growth-hormone-releasing hormone (GHRH) regulates release of growth hormone (GH), and corticotropin-releasing factor (CRF) regulates adrenocorticotropic hormone (ATCH) release from the anterior pituitary. Thyroid-stimulating hormone (TSH) is released from the anterior pituitary and stimulates release of T3 and T4 from the thyroid.

Cortisol is a hormone secreted by the adrenal cortex. The adrenal cortex is first stimulated by adrenocorticotropic hormone, which is secreted from the anterior pituitary gland.

Signals from the hypothalamus go to the posterior pituitary gland, which is located at the base of the hypothalamus. The pituitary consists of two lobes (anterior and posterior), which function independently. The anterior and posterior pituitary produce a collection of hormones that are key to endocrine signaling throughout the body. 

The posterior pituitary stores and secretes two hormones (oxytocin and vasopressin), while the anterior pituitary produces six different hormones (growth hormone, prolactin, follicle-stimulating hormone (FSH), luteinizing hormone (LH), thyroid-stimulating hormone (TSH) and adrenocorticotropic hormone (ACTH). The posterior pituitary will only secrete hormones when stimulated by the hypothalamus.

The anterior pituitary gland contains endocrine cells that release hormones through the hypothalamic-hypophyseal axis. Prolactin controls milk production and contributes to regulation of the immune system. Of the listed hormones, prolactin is the only hormone released from the anterior pituitary.

Insulin and glucagon are secreted by the pancreas. Cortisol is released by the adrenal cortex; epinephrine is released by the adrenal medulla.

Melatonin is secreted by the pineal gland, which is also in the brain. The function of melatonin is not yet certain, but current research hints that it plays functions in regulation of the circadian rhythm. All other hormones are indeed secreted by the pituitary gland.