hypothalamus

n. area of the brain which controls the autonomic nervous system

The hypothalamus links the nervous system to the endocrine system via the pituitary gland (hypophysis). The hypothalamus, (from Greek ὑποθαλαμος = under the thalamus) is located below the thalamus, just above the brain stem. This gland occupies the major portion of the ventral region of the diencephalon. It is found in all mammalian brains. In humans, it is roughly the size of an almond.
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Hypothalamus /hy·po·thal·a·mus/ the part of the diencephalon forming the floor and part of the lateral wall of the third ventricle, including the [more]Hypothalamus - Community and Resources

Noun
1. a basal part of the diencephalon governing autonomic nervous system
(hypernym) neural structure
(part-holonym) diencephalon, interbrain, betweenbrain, thalmencephalon

n. hypothalamus, area of the brain which controls the autonomic nervous system