Structure and Functions of Yellow Elastic Tissue
As indicated on the page about classification of animal tissue types, Yellow Elastic Tissue is a form of mature (rather than embryonic) connective tissue and is one of the forms of dense connective tissue.
There are three (3) types of dense connective tissue.
The 3 forms of Dense Connective Tissue:
Yellow elastic tissue is connective tissue in which (yellowish, when unstained) elastic fibres dominate the tissue structure resulting in the mass of tissue having a yellow-ish appearance and considerable elasticity. That is, the tissue is able to extend when forces are applied to stretch it, yet return undamaged to its previous condition when the (extending) force is realeased.
Structure of Yellow Elastic
The main constituents of yellow elastic tissue are many freely-branching elastic fibres (which are responsible for the yellowish colour of the tissue). Chemically, the elastic fibres are elastin, which is composed of the amino acids glycine, valine, alanine, and proline.
Fibroblast cells (called "fibrocytes") are also widely present distributed throughout the structure of yellow elastic tissue (as well as those of other connective tissues, such as white fibrous tissue) and are necessary for production of the precursors of many constituents of tissues including those of elastic fibres, and reticular fibres (which are microscopic, non-elastic branching fibres).
Functions of Yellow Elastic Tissue:
Yellow elastic tissue enables organs and parts of organs to stretch (and contract).
This is important when the function of the organ involves movement incl. expansion and contraction of membranes e.g. of lung tissue.
Locations in the body:
Yellow elastic (connective) tissue is present in many locations throughout the body, including:
- Lung tissue.
- Walls of elastic arteries.
- Trachea (windpipe).
- Brochial tubes.
- Thyroid ligaments.
Warnings of possible confusion:
Other types of (animal, including human) tissue include the word "yellow" in their name and/or description but do not necessarily have connection or similarity with the connective tissue described here as "yellow elastic tissue" - other than their name, and perhaps to some extent their colour.
Other "Yellow" tissues:
The following are listed for reference and completeness.
(of the eye)
The macula lutea is also known as the yellow spot.
It is the area on the retina (at the back of the eye) which surrounds the greatest concentration of cones (a type of light-sensing cell located at the back of the eye and essential for colour vision).
Obviously not a "tissue type", Yellow Fever is an infectious tropical disease transmitted by mosquitoes. It is mentioned here both because of its name, and because one of its symptoms is jaundice - the term for yellowing of the skin or whites of the eyes, indicating excess bilirubin in the blood: Note that skin/eyes yellowed due to jaundice are not "yellow elastic tissue", merely yellowed in colour as a result of the condition.