The submandibular lymph nodes (submaxillary glands in older texts) are lymph nodes beneath the body of the mandible in the submandibular triangle, and rest on the superficial surface of the submandibular gland.
One gland, the middle gland of Stahr, which lies on the facial artery as it turns over the mandible, is the most constant of the series; small lymph glands are sometimes found on the deep surface of the submandibular gland.
The afferents of the submandibular glands drain the medial canthus, the cheek, the side of the nose, the upper lip, the lateral part of the lower lip, the gums, and the anterior part of the margin of the tongue.
Efferent lymph vessels from the facial and submental lymph nodes also enter the submandibular glands. Their efferent vessels pass to the superior deep cervical lymph nodes.
Nitric oxide (nitrogen oxide or nitrogen monoxide) is a colorless gas with the formula NO. It is one of the principal oxides of nitrogen. Nitric oxide is a free radical: it has an unpaired electron, which is sometimes denoted by a dot in its chemical formula (N=O or NO). Nitric oxide is also a heteronuclear diatomic molecule, a class of molecules whose study spawned early modern theories of chemical bonding. An important intermediate in industrial chemistry, nitric oxide forms in combustion systems and can be generated by lightning in thunderstorms. In mammals, including humans, nitric oxide is a signaling molecule in many physiological and pathological processes. It was proclaimed the "Molecule of the Year" in 1992. The 1998 Nobel Prize in Physiology or Medicine was awarded for discovering nitric oxide's role as a cardiovascular signalling molecule. Nitric oxide should not be confused with nitrogen dioxide (NO2), a brown gas and major air pollutant, nor with