1 Cold sores later crust over with a scab and are usually associated with tingling, tenderness, or burning before the actual sores appear. 2  Mouth irritation. 3  The irritation can be caused by: 4  Biting your cheek, tongue, or lip. 5  Wearing braces or another type of dental apparatus, or having a sharp, broken tooth.
Main Image: The Pituitary gland is a pea-sized endocrine (hormone-producing) gland weighing about 0.5 g situated at the bottom of the skull sandwiched between the optic nerves, in humans. The pituitary gland secretes hormones. Hormones are chemicals that travel through the blood stream.
Hormones are produced by endocrine glands. In humans and many other animals, hormones are either peptide hormones (modified amino acids, peptides, small proteins) or steroid and steroid-like hormones. The endocrine glands are ductless glands and secrete hormones directly into the blood vessels nearby. The hormones are then carried throughout the body and act upon target cells and tissues. The target cells have protein receptors which recognize the hormone and bind it. This interaction of the hormone and its specific receptor occurs either in the cell membrane (amino acid, peptide, or small protein hormone) or in the cell interior (steroid hormones).