The hypodermis is the innermost and thickest layer of the skin. It invaginates into the dermis and is attached to the latter, immediately above it, by collagen and elastin fibres. It is essentially composed of a type of cells specialised in accumulating and storing fats, known as adipocytes.
Fatal familial insomnia Fatal familial insomnia (FFI) is a very rare, autosomal dominant inherited, disease of the brain. It is caused by a mutation in a protein called prion protein (PrP): asparagine-178 is replaced by aspartic acid.
Insomnia may be divided into three classes based on the duration of symptoms. 1  Insomnia lasting one week or less may be termed transient insomnia; 2  short-term insomnia lasts more than one week but resolves in less than three weeks; and.  long-term or chronic insomnia lasts more than three weeks.