The group of cells that have a similar structure and they combine together to perform a required function. In French, the word tissue means ‘to weave’. In animals, there are four different types of tissues, they are epithelial tissue, connective tissue, nervous tissue, and muscle tissue.
Let us learn more about ligament connective tissue: its structure, functions, and types
What is a Ligament?
The ligament is a connective tissue that provides support to the organs and connects the bones together. They are short bands of tough and flexible tissue that are made up of lots of individual fibers. The human body is made up of approximately 900 ligaments.
The building blocks of ligaments are collagen fibers. Each of the collagen fibers combines to form a bundle that is made up of a collagen matrix with scattered fibroblasts that are responsible for the synthesis and repair of collagen.
The composition of the ligament is as follows: two-thirds of the ligament’s weight is water which provides its main characteristic feature viscoelastic properties. The remaining one-third is a mixture of collagen, glycoproteins, elastin, and proteoglycans.
At the molecular level, in the extracellular spaces, the collagen is synthesized as procollagen molecules, then the helical collagen molecules are arranged in a line to form fibrils and subsequently collagen fibers that make up the ligament. Lysyl oxidase is the enzyme that promotes the placement of cross links within and in between the collagen molecules. The created crosslinking adds up the tremendous characteristic strength to the ligamentous structures.
The microstructure of ligamentous structures is made up of collagen bundles aligned along the long axis of the ligament with a crimp or “waviness” along its length. Crimp is said to play a specialized biomechanical role during the process of loading, by allowing the collagen fibers to straighten, so that the ligament may elongate without any kind of damage in the tissue under a constant or cyclically repetitive load.
[Fig: Ligament diagram]
The function of the ligaments are as follows:
Types of Ligaments
Capsular ligaments are part of the articular capsule that surrounds synovial joints and they also provide mechanical reinforcements.
The extracapsular ligaments join together with the available other ligaments to provide joint stability.
The intracapsular ligaments are much less common and also provide stability for the larger range of motion.
Cruciate ligaments are paired ligaments that are in the form of a cross.
Ligaments are viscoelastic, that is when under tension they can strain gradually, and when the tension is removed they can retain their original position. However, the only disadvantage is they cannot retain their original shape when extended past a certain point or for a prolonged period of time. Due to this reason, it is said that the dislocated joints should be set as quickly as possible. If the ligaments are stretched too much, then the joint will be weakened that results in the dislocation of bones.
Certain folds of the peritoneum are referred to as ligaments.
The hepatoduodenal ligament surrounds the hepatic portal vein present in the gastrointestinal tract and other vessels as they carry blood from the duodenum to the liver.
The broad ligament of the uterus, also a fold of the peritoneum.
Fetal Remnant Ligaments:
Some of the tubular structures found during the fetal period are referred to as ligaments after which they close up and turn into cord-like structures.
Ligaments are similar to fasciae and tendons as they are all made of connective tissue. The only difference among them is in the connection that they make internally: ligaments connect one bone to another bone, where the tendons connect muscle to bone, and fasciae connect muscles to other muscles. All of these are found in the skeletal system of the human body. Ligaments cannot be regenerated naturally.