Head and neck anatomy speech (phonation). In addition to the teeth, other structures that aid chewing are the lips, cheeks, tongue, hard palate, soft palate, and floor of the mouth. Several glands of the endocrine system are found within the head and neck. Endocrine means that the secretion is used within the body. Endocrine glands are termed as ductless and release their secretions directly into the blood. The endocrine system is under the direct supervision of the nervous system, using the negative feedback principal of homeostasis, to create hormones which act as chemical instant messengers. The hypothalamus connects directly to the pituitary gland, both
Homeostasis regulating metabolism, reproduction, eating and drinking behaviour, energy utilization, osmolarity and blood pressure. The regulation of metabolism, is carried out by hypothalamic interconnections to other glands. Three endocrine glands of the hypothalamic–pituitary–gonadal axis (HPG axis) often work together and have important regulatory functions. Two other regulatory endocrine axes are the hypothalamic–pituitary–adrenal axis (HPA axis) and the hypothalamic–pituitary–thyroid axis (HPT axis). The liver also has many regulatory functions of the metabolism. An important function is the production and control of bile acids. Too much bile acid can be toxic to cells and its synthesis can be inhibited by activation of FXR