II.

Anatomy

The human hypothalamus weighs about 4 g (0.14 oz) and is found behind the eyes, directly below the brain's thalamus and above the pituitary gland. The hypothalamus is divided into several distinct nuclei, that is, aggregates of nerve cell bodies. These nerves connect the brain with the hypothalamus and the hypothalamus to virtually all regions of the nervous system. The hypothalamus also receives nerve inputs from the erogenous zones (the genitalia and nipples), the viscera (internal organs), and the limbic system (concerned with motivation and drive).