Specialized ganglionic sympathetic neurons that release hormones into the bloodstream are found within the

Suprarenal glands.

Explanation:

Sympathetic neurons are included both in the peripheral nervous system as well as in the central nervous system. These neurons are mainly active during the fight and flight condition of the body.

The suprarenal glands produce the different hormones that by the innervation of the sympathetic neurons. These hormones release adrenaline and nor adrenaline in the fight and flight conditions of the body. These hormones helps in increasing heart rate, dilates pupil in emergency situation.

Thus, the answer is suprarenal glands.