Microscopic image of human salivary gland tissue showing epithelium tissue, connective tissue, serous and mucous glands. Credit: Tinydevil/ Shutterstock Images
A recent study described a dense collection of bilateral submucosal glands at the top of throat as a new organ and a pair of salivary glands. Anatomists from India have now debunked this finding1.
Researchers at the All India Institute of Medical Sciences Patna have shown through biochemical analyses that the glands do not secrete an essential enzyme present in human saliva, which means they cannot contribute significantly to saliva.
These glands are not an isolated mass, the researchers say, and lack the independent blood and nerve supply, and lymphatic drainage that characterise an organ.
The glands are located at the end of the auditory tube, which is described as a part of the respiratory tract in anatomy textbooks.
To reinvestigate and verify the glands, the scientists, led by Ashutosh Kumar, dissected human cadavers. They looked for saliva-specific markers such as amylase enzyme, and tissue-specific markers in the salivary glands and respiratory tract. They also examined nasopharyngeal swab samples from living human volunteers to detect amylase.
The team, which included researchers at the Postgraduate Institute of Medical Education and Research in Chandigarh, did not find any traces of amylase. The glands’ location also makes it very unlikely that their mucous content could reach the oral cavity and contribute to saliva.
“The morphological and functional similarity to the seromucous glands in the respiratory tract, and the absence of salivary amylase strongly indicate that these glands are different from the salivary glands,” says Kumar.
