Spinal tissue should be the answer.
The answer is semicircular canals. The part of the ear responsible for hearing and balance is the inner ear. The inner ear is composed of three parts: the cochlea's role is for hearing, the semicircular canal is for balance and the last, the vestibule connects the two parts to other structures in the ear.
The pituitary gland is connected to the hypothalamus. The pituitary is a pea sized organ that controls hormones. What the hypothalamus does is control body temperature, thirst, hunger, and other homeostatic systems, and involved in sleep and emotional activity. The hypothalamus needs the pituitary to be active because the pituitary makes the decision of what people are feeling in their body, and the hypothalamus releases those feelings into the body.