Cartilage Collagens
Marcel E. Nimni in Collagen, 1988
Hyaline cartilage is the most common and well-characterized type of cartilage which covers the articular surface of bones and supports tracheal tubes, larynx, and ventral ends of ribs. It also provides the embryos with temporary skeletons which are eventually resorbed and replaced by bone. Hyaline cartilage is, as the name implies, semitransparent glassy tissue with an opalescent bluish-white tint. Microscopically, the intercellular substance appears homogenous and structureless, because the collagen fibers are relatively small in size and thickness and are masked by amorphous ground substance in which they are embedded (Figure 1). When typical hyaline cartilage is observed under an electron microscope, collagen appears as a branching meshwork of fine fibrils (diameter 10 to 20 nm) which is lacking in characteristic cross-striation pattern.11 Adult articular cartilage, however, often contains larger fibrils (diameter 30 to 200 nm) with cross striation of 64-nm periodicity.12 Apart from the morphological heterogeneity, the great majority of these fibers is derived from type II collagen molecules which consist of three identical α1(II) chains.13,6
Revisioning Cellular Bioenergetics
Aruna Bakhru in Nutrition and Integrative Medicine, 2018
In addition, Pollack (2015) explains that EZ water is the reason why joint sockets do not squeak because of frictional resistance during rotation under pressure, despite being situated at sites where bones abut one another. Hyaline cartilage, a semirigid avascular connective tissue consisting of a matrix of protein fibers in a gel-like ground substance, cocoons the ends of the bones to provide a sliding surface at joint articulations. Joints are in turn lined by fibrous areolar connective tissue enclosed by a layer of cuboidal or squamous epithelial cells devoid of a basement membrane called the synovial membrane, which consists of cells that secrete synovial fluid to decrease friction in the joint cavity. Because cartilage is a highly charged polymeric-like gel material, cartilage grows layers of EZ water in response to light (Pollack, 2015).
Structure and Function of Cartilage
Kyriacos A. Athanasiou, Eric M. Darling, Grayson D. DuRaine, Jerry C. Hu, A. Hari Reddi in Articular Cartilage, 2017
Hyaline cartilage is also found in the ends of the ribs, larynx, tracheal rings, bronchi, ears, sclera of the eye, and nose, where it is covered by perichondrium. Another hyaline cartilage structure is the the epiphyseal (growth) plate, in the metaphysis (wider region at the end of the long bones), responsible for the elongational growth of bones. The growth plate organizes into multiple zones of differentiating chondrocytes in columns. These zones include undifferentiated cartilage cells (resting zone), proliferating cells (responsible for volume increases), hypertrophic cells (cells enlarged and aligned in columns, and beginning to undergo apoptosis), and calcified cells (where cartilage is replaced by bone). As skeletal development and maturation proceed, chondrocytes undergo terminal differentiation into hypertrophic chondrocytes, and the growth plates calcify and are eventually replaced by bone, at which point the bone stops elongating (Johnston 1997). Defects or injuries to the growth plate commonly result in shortening of the affected bone, as longitudinal growth is impaired. Long bone growth defects may lead to growth disorders such as achondroplasia, the most common cause of dwarfism.
3D-printed porous tantalum: recent application in various drug delivery systems to repair hard tissue defects
Published in Expert Opinion on Drug Delivery, 2021
Long Hua, Ting Lei, Hu Qian, Yu Zhang, Yihe Hu, Pengfei Lei
Cartilage, the principal function of which is to distribute pressure, has a certain tolerance and elasticity [66–69]. Cartilage can be divided into the superficial zone, the transitional zone, the deep zone, the calcified cartilage, and the subchondral bone. The first three layers are defined as hyaline cartilage. Sports injury and long-term wear can cause cartilage damage [70]. Owing to the deficiency of blood supply, cartilage damage is often difficult to repair [61,71–74]. Sports injury may cause subchondral bone collapse and nonunion [75,76]. Thus, the repair of cartilage after injury must consider the cartilage plane, sub-cartilage plane, and bone–cartilage interface [77]. In the classical model of chondrocyte induction, cartilage needs some mechanical support to promote growth, including compressive force and tensile force [78]; compressive forces stimulate the formation of hyaline cartilage, whereas tensile force leads to the formation of fibrocartilage. Therefore, the design of scaffolds needs to consider the characteristics of human bone and cartilage and be similar to the host subchondral bone for cartilage repair.
Advances in stem cell therapy for cartilage regeneration in osteoarthritis
Published in Expert Opinion on Biological Therapy, 2018
Leire Iturriaga, Raquel Hernáez-Moya, Itsasne Erezuma, Alireza Dolatshahi-Pirouz, Gorka Orive
Chondrocytes, the only cell type of hyaline cartilage, represent 1–5% of its total components and are responsible for generating and restoring the ECM of which this tissue is also composed. In general, ECM is composed mainly of water, representing the 65–80% of its total weight and collagen fibers, 90% of which are collagen type II. These two components are distributed in well organized and interconnected four layers providing cartilage with the ability to transfer stress forces (Figure 1). The rest of the joint cartilage (10–20%) consists of decorin, biglycans, and proteoglycans, especially aggrecans. These components bind to hyaluronic acid (HA) via two molecules, namely chondroitin and keratan sulfate [22]. Differences in the morphologies of zonal subpopulations of chondrocytes may reflect matrix composition and are ascribed largely to differences in the mechanical environment [23].
Acromioclavicular joint injuries at a Colorado ski resort
Published in The Physician and Sportsmedicine, 2023
Naomi Kelley, Lauren Pierpoint, Jack Spittler, Morteza Khodaee
Acromioclavicular joint (ACJ) injuries (also known as separations or dislocations) are very common, accounting for up to forty percent of all shoulder injuries [1–4]. The AC joint is a diarthrodial joint where the clavicle can rotate and translate anteriorly, posteriorly and inferiorly in relation to its articulation with the acromion. The joint is composed of a meniscus-type structure of hyaline cartilage, surrounded by synovium [2]. Stability of the ACJ is provided horizontally by the acromioclavicular ligament, and vertically by the coracoacromial ligament. Although not directly attached to the acromion, two coracoclavicular ligaments (conoid and trapezoid ligaments) provide further vertical stability to the joint [5]. Overall, the anatomy of the ACJ provides resistance against significant forces.
Related Knowledge Centers
- Cartilage
- Diffusion
- Hyaline
- Perichondrium
- Synovial Membrane
- Trachea
- Type II Collagen
- Rib
- Larynx
- Nerve
- Type II Collagen