Final answer:
The link between the brain and the glandular system is the hypothalamus, which communicates with the pituitary gland.
Step-by-step explanation:
The link between the brain and the glandular system is the hypothalamus. The hypothalamus is a structure located in the brain that is responsible for regulating various functions of the body, including the endocrine system. It communicates with the pituitary gland, which is considered the master gland of the endocrine system, through a thin stalk called the infundibulum.