The body is filled with all kinds of tissue (four different types, to be exact), the most abundant being connective. Ligaments, tendons, cartilage, joint capsules, fascia, adipose, even your blood and your bones are all classified as connective tissue. I’m mostly going to be talking about fascia in this series, but it’s worth mentioning that all types of connective tissue are made up of various amounts of the following three things: cells, fibers and a watery fluid called ground substance.
What Kind of Cells?
Fibroblasts are the most abundant cells in connective tissue and their job is to produce the various types of fibers found in the various types of connective tissue. I’ll be talking lots more about collagen specifically in upcoming parts of this series and the role it plays in yin yoga and massage therapy.
Mast cells, which are associated with the processes of inflammation and healing, are found all throughout connective tissue but are the most highly concentrated around blood vessels. They secrete heparin (an anticoagulant that prevents blood clotting) and histamine (which causes the blood vessels to open wider, aiding in the inflammatory response).
The third type of cell present in all connective tissue is a type of phagocyte called a macrophage. Macrophages play a key role in general immune defense by eating and thereby destroying microbes and cellular debris that make it past other physical and chemical barriers like skin and mucus membranes. Macrophage translates to “big eater” so these cells can ingest up to 100 foreign objects before they die and we eliminate them.
What Kind of Fibers?
There are three types of fibers found in connective tissue, all are made up of protein chains secreted by the fibroblasts. Collagen is the thickest, strongest and most abundant protein in the body. It’s highly concentrated in load bearing structures like tendons, ligaments and bones. There’s also elastin, a smaller more flexible protein that can stretch up to 150% it’s normal length without tearing and then quickly recoil. This is very different from collagen in that collagen doesn’t have the ability to stretch without causing structural damage (though it can and does lengthen, more on that later). Reticulin is a thinner, much more delicate and also flexible type of collagen and can be found surrounding and supporting organs and nerves. It can also be found in the endomysium, which is the layer of fascia that surrounds each individual muscle cell.
What is Ground Substance?
In his book “Fascia: What it is and why it matters” David Lesondak says, “Ground substance is a viscous, fluid environment where chemical exchanges take place in the body, and molecular exchanges between blood, lymph and tissue cells happen.” To add to that, Deane Juhan wrote in his book “Job’s Body” that ground substance is “the immediate environment of every cell in your body.” It functions as the lubricant of all connective tissue, so when it’s dehydrated the fibers lose their ability to slide and glide over one another and adhesions (aka knots) form. Fascia is different from other types of connective tissue because it contains more ground substance than say a bone or ligament.
What is Fascia?
At the Fourth International Fascia Research Congress in 2015, Carla Stecco declared that, “Fascia is a sheath, a sheet, or any number of other dissectible aggregations of connective tissue that forms beneath the skin to attach, enclose, and separate muscles and other internal organs.” Before that though, at the First International Fascia Research Congress in 2007 it had been defined by Robert Schleip and Thomas Findley as “the soft tissue component of the connective tissue system that permeates the human body, forming a whole-body continuous three-dimensional matrix of structural support. It interpenetrates and surrounds all organs, muscles, bones and nerve fibers, creating a unique environment for body systems functioning.”
The fascia is similar to saran wrap. You know what a mess that is to unstick once you get it balled up? When fascia is healthy its fibers are meant to slide and glide past one another and other structures. When it’s unhealthy and dehydrated, adhesions form and a decrease in immune function and healing processes can occur. More info about adhesions (what they are and how they form) coming in a later post. You can read all about the facial layers here and here.