noun, plural: tectums, tecta
A roof-like covering or structure
Tectum is a term used to describe a structure resembling a roof. For instance, the roof-like dorsal part of the mesencephalon is called the tectum of mesencephalon (or the tectum of midbrain). It is at the dorsal part of the midbrain (mesencephalon) as opposed to the tegmentum, which is at the ventral region. The tectum is associated with auditory and visual reflexes. It is derived from the alar plate of the neural tube during embryogenesis. In adults, it is made up of the superior colliculus and the inferior colliculus. The superior colliculus is associated with the visual processing whereas the inferior colliculus is involved in auditory processing.
Tectum is also used to refer to the roof-like protrusions on the outer surface of a pollen or a spore. When a pollen grain has tecta on its outermost layer, it is described as tectate. When there are no tecta, the pollen is described as intectate. In the presence of perforations resulting in discontinuous layer of tecta, the pollen grain is described as semitectate.
Word origin: Greek tégos (“roof; any covered room of a house”)