Lamellar tissues are a type of connective tissue which have a regular, repeating pattern of collagen fibers allowing them to be highly abnormal resistant to unidirectional stress. They are found in the tendons and ligaments of the human body, as well as supporting a variety of organs such as the vertebral column, diaphragm, and walls of the heart. Their purpose is to provide strength and elasticity to these structures, allowing them to flex and stretch, and to transfer force through the body.
Lamellar tissues are composed of collagen fibers arranged into layers (lamella) which are angled so that the fibers of one layer overlap with the fibers of the next layer. Each of these fibers has a high tensile strength, so that when subjected to tensile stress the fibers take the strain, rather than the individual layers. This overall arrangement gives the tissue compressive as well as tensile strength, and accounts for its resistance to damage from unidirectional stress.
The arrangement of the collagen fibers in lamellar tissue is commonly referred to as the “Lamellar Offset”. This offset is typically made up of offsets between 3-10 degrees, with most offsets at around 6-8 degrees. This arrangement allows the layers to be tightly bound together, making the tissue very strong, while still allowing it to be somewhat flexible and elastic.
In addition to collagen, lamellar tissue also contains proteoglycans. These are molecules composed of protein and a large number of small carbohydrate strands known as glycosaminoglycans (GAGs). Proteoglycans are important for providing lubrication and cushioning between the layers. They also provide a permeability barrier, raising the osmotic pressure between the lamellar layers and preventing the diffusion of fluid into the core of the tissue.
The most common type of lamellar tissue is the Sharpeys fiber. Sharpeys fibers, also known as Sharpeys lines, are a type of collagen fiber which links separate parts of the body. They are found in tendons, ligaments, and skin, and provide a stable structure for them to attach to. These fibers are composed of smaller and more wavy collagen fibers that are arranged into layer-like structures and are held in place by proteoglycans.
The structure of lamellar tissue and Sharpey’s fibers makes them ideal for providing support and forming connections between tissues and structures. They are found in a wide variety of body organs and tissues, providing strength and elasticity to tendons, ligaments, skin, cartilage, and bones. Their ability to resist unidirectional stress, as well as their permeability, lubrication, and cushioning makes them essential to the functions of many organs and tissues.
