Which Type Of Connective Tissue Would Be Harder For The Body To Repair, Cartilage Or Bone

Introduction

Cartilage has many functions, including the ability to resist compressive forces, raise bone resilience, and provide support on bony areas where at that place is a need for flexibility. The primary cell that makes cartilage is the chondrocyte, which resides inside the lacunae. The matrix of cartilage consists of gristly tissue and diverse combinations of proteoglycans and glycosaminoglycans. Cartilage, in one case synthesized, lacks lymphatic or blood supply and the movement of waste and nutrition is chiefly via diffusion to and from adjacent tissues. Cartilage, similar bone, is surrounded by a perichondrium-like fibrous membrane. This layer is non efficient at regenerating cartilage. Hence, its recovery is slow after injury. The lack of agile blood flow is the major reason any injury to cartilage takes a long time to heal. Cartilage has no nervus innervation, and hence at that place is no sensation when it is injured or damaged. When there is calcification of cartilage, the chondrocytes die. This is followed past the replacement of cartilage with bone-like tissue. Unlike os, cartilage does not take calcium in the matrix. Instead, it contains loftier amounts of chondroitin, which is the material that provides elasticity and flexibility.

Structure and Function

Several types of cartilage are found in the human body, and their structure and relevant function depend on this variation.

Hyaline Cartilage

Hyaline cartilage is the most copious type of cartilage in the human torso.[i] It has a pale blue-white color and is smooth to the impact. Information technology is primarily composed of type Ii collagen and proteoglycans. The surface is usually moist, but with age, the cartilage becomes dry, thinner, and more yellowish. Hyaline cartilage is usually found in the trachea, nose, epiphyseal growth plate, sternum, and ventral segments of the ribs. Hyaline cartilage produces a resilient surface with minimal friction. It also has an excellent ability to resist compressive forces at sites of bone joint.[two]

Rubberband Cartilage

This cartilage appears a dull yellow and is most unremarkably establish in the larynx, ear, epiglottis, and eustachian tube. A perichondrium-like layer also surrounds it. Information technology provides flexibility and is resilient to force per unit area.[3]

Fibrocartilage

This is abundant in type 1 collagen and contains significantly less proteoglycan than hyaline cartilage. Information technology tin can resist high degrees of tension and compression. Information technology is ordinarily found in tendons, ligaments, intervertebral discs, articular surfaces of some bones, and in menisci. Unlike other cartilage, it has no perichondrium.[four]

Embryology

Cartilage is formed from the mesoderm germ layer by the procedure known as chondrogenesis.[v] Mesenchyme differentiates into chondroblasts, which are the cells that secrete the major components of the extracellular matrix—the most important of these components for cartilage formation being aggrecan and blazon II collagen. Once initial chondrification occurs, the immature cartilage grows mainly by developing into a more mature land since it cannot grow by mitosis. There is minimal cell division in cartilage; therefore, the size and mass of cartilage do non modify significantly after initially chondrification.

Blood Supply and Lymphatics

Cartilage is avascular. This characteristic of cartilage is paramount during the discussion and management of diseases affecting cartilage. Since there is no direct blood supply, chondrocytes receive nourishment via improvidence from the surrounding environment. The compressive forces that regularly act on cartilage as well increase the diffusion of nutrients. This indirect process of receiving nutrients is a major cistron in the dull turnover of the extracellular matrix and lack of repair seen in cartilage.

Nerves

Cartilage does not comprise nerves; it is aneural.[vi] If any pain is associated with a pathology involving cartilage, it is nigh ordinarily due to irritation of surrounding structures, such as inflammation of the joint and bone in osteoarthritis.

Muscles

Fibrocartilage is a major component of entheses, divers every bit the connective tissue between muscle tendon or ligament and bone. The fibrocartilaginous enthesis consists of four transition zones as it progresses from tendon to os.[7] These transition zones are listed in order of progression from musculus to bone.

Longitudinal fibroblasts and a parallel arrangement of collagen fibers are establish in the tendinous area
A fibrocartilaginous region where the chief blazon of cells present transitions from fibroblast to chondrocytes
A region chosen the "blue line" or "tide marking" due to an precipitous transition from cartilaginous to calcified fibrocartilage
Os

Physiologic Variants

Literature shows many anatomical variants of cartilage, and in many cases, this can bear upon the pathology associated. For case, a report showed a significant correlation betwixt novel genetic variants in cartilage thickness and the incidence of hip osteoarthritis.[eight]

Clinical Significance

An immense variety of clinical pathology exists involving cartilage, such as osteoarthritis, spinal disc herniation, traumatic rupture/disengagement, achondroplasia, costochondritis, and neoplasm, and many others. These result from a diverseness of degenerative, inflammatory, and congenital causes.

Osteoarthritis is a disease affecting the whole joint; nevertheless, the articular cartilage (a subset of hyaline cartilage) within the joint is the most afflicted tissue. Osteoarthritis is known equally a "habiliment and tear" phenomenon due to it mainly affecting joints nether higher amounts of stress. It results due to articular cartilage being thinned and wearing away. This ultimately results in a decreased range of movement, "bone against os" contact within the joint, and pain. The initial clinical treatment is with anti-inflammatories and corticosteroid injections intraarticularly. Both therapies office to reduce the inflammatory reaction acquired past the degenerative cartilage's release of cytokines. Patients may besides evidence improvement by losing weight, exercising, and efforts to decrease joint stress with rest and using a cane. Somewhen, even so, many patients will develop pain and symptoms that interfere with daily life. At this bespeak, joint replacement or resurfacing may exist recommended. Arthroscopic surgery is no longer recommended as it does not ameliorate outcomes in knee osteoarthritis and can cause harm.

Another mutual degenerative disease of cartilage is spinal disc herniation. It is due to degenerative changes of the outer ring of the intervertebral disc, called the annulus fibrosus. The annulus fibrosus is composed of fibrocartilage. Trauma, straining, and lifting injuries are too implicated in the weakening of the annulus fibrosis predisposing to disc herniation. When there is structural harm to the annulus fibrosus, the nucleus pulposus contained within the disc may herniate into the spinal canal, causing impingement of i or multiple nerves as well every bit induce inflammatory changes due to the damaged fibrocartilage.[9] Diagnosis is made by history, symptoms, and physical test. At some point in the evaluation, imaging studies are usually conducted to rule out other causes such as tumors, spondylolisthesis, and space-occupying lesions. Although some patients warrant surgery due to the severity of symptoms, nigh cases exercise not require surgical intervention as they resolve with conservative measures such as anti-inflammatories and lifestyle changes for the patient.

In contrast to the degenerative diseases of cartilage, Achondroplasia is a genetic disorder of cartilage formation and is the about mutual cause of dwarfism. The pathology seen is due to a mutation on chromosome 4 bear upon the fibroblast growth factor receptor iii (FGFR3) cistron, which normally functions every bit a negative regulator of bone and cartilage growth. The mutation in achondroplasia results in a truncated dysfunctional poly peptide that is constitutively agile. These dysfunctional proteins impede cartilage growth and evolution by suppressing chondrocyte proliferation and calcification.[x] The diagnosis of achondroplasia is usually during pregnancy via prenatal ultrasound. At that place is currently no known cure for achondroplasia as it is not affected by a hormone pathway that tin can be pharmacologically manipulated, and corrective surgery is controversial.[11]

Review Questions

Figure

Cartilage, Bone. Contributed Illustration by Beckie Palmer

Figure

Triangular Fibro Cartilage Complex. Contributed by Katherine Humphries

Figure

Earlobe, cartilage, soft tissue and cutis of the external ear. H/E 4x. Contributed by Fabiola Farci, MD

Figure

Cartilage, H/E 20x. Contributed by Fabiola Farci, Medico

Figure

Cartilage and nerves, H/E 4x. Contributed by Fabiola Farci, Dr.

References

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