Cartilage is a flexible connective tissue that differs from bone in several ways; it is avascular and its microarchitecture is less organized than bone. Rheumatoid arthritis (RA) is a disease process where the body’s immune system attacks synovial cells, and therefore the lining of joint capsules, which is a tough membrane that encloses joints. Cartilage. • Newly formed chondroblasts secrete matrix around themselves, creating superficial lacunae beneath the perichondrium. Additionally, a glycoprotein known as lubricin that is abundant in the superficial layer of cartilage and synovial fluid plays a major role in bio-lubrication and wear protection of cartilage. So, you can find hyaline cartilage in the larynx and trachea in the throat portion of the body, and then also in all of the joints where the surfaces of bones are articulating each other. This smooth, transparent, glassy type of cartilage coats the ends … Your email address will not be published. Our engaging videos, interactive quizzes, in-depth articles and HD atlas are here to get you top results faster. From the cartilaginous tissue a kind of hard semi-transparent organic substance is secreted which is known as *Chondrin*. This type of cartilage contains elastic fiber networks and collagen fibers. They are found on many joint surfaces. b) Elastic cartilage. Interstitial growth is the result of continued mitosis of early chondroblasts throughout the tissue mass and is obvious only in young cartilage, where the plasticity of the matrix permits continued expansion. It contains no nerves or blood vessels, and its structure is relatively simple. Hyaline cartilage is the most abundant type of cartilage in the body. Elastic cartilage has the most ECM; hyaline a middle amount; and fibrous cartilage has the least amount of ECM. This zone is the thickest layer of round chondrocytes, with abundant proteoglycan content. Transmission electron microscopy reveals that they have a characteristic cross-banding (65 nm periodicity) and are interwoven to create a three-dimensional meshwork. This causes it to heal very slowly. While more rigid and less flexible than muscle, cartilage is not as stiff as bone. In the embryo , it provides support and is a precursor to bone . Register now It has a capacity for rapid interstitial and appositional growth in young and growing tissues. If a thin slice of cartilage is examined under the microscope, it will be found to consist of cells of a rounded or bluntly angular form, lying in groups of two or more in a granular or almost homogeneous matrix. As mentioned before, the ECM is paramount in opposing shear, tensile, and compressive forces normally. These cells have generally straight outlines where they are in contact with each other, with the rest of their circumference rounded. from IGNOU and have completed a Diploma in Medical Laboratory Technology from Young Women Christian Association (YWCA) institute. Other constituents of cartilage include dissolved salts, non-collagenous proteins, and glycoproteins. Three α chains intertwine into a triple helix, forming a procollagen molecule. The collagen of articular cartilage is primarily type II (90–95%), with small contributions from types IX and XI. Cartilage function is more than structural, and has different functions in the life cycle. Healthy articular cartilage allows joints to move and glide over each other with very little friction, but is subject to damage and injury, as well as normal wear and tear. It is a different form of connective tissue. It owes its flexibility and toughness to the fibrous tissue and its elasticity to the cartilaginous tissue. and grab your free ultimate anatomy study guide! It works just like a cushion in the joints. –  There are two types of which are the following: – Chondroblast – It is a type of cell that develops into a chondrocyte or cartilage cell. “I would honestly say that Kenhub cut my study time in half.” Fibrocartilage is found in the pubic symphysis, the annulus fibrosus of intervertebral discs, menisci, and the temporal-mandibular joint. Hyaline cartilage, the most abundant type of cartilage, plays a supportive role and assists in movement. the elbows, knees, and ankles, ends of the ribs, Between the vertebrae in the spine, ears, and nose, Bronchial tubes or airways. Articular cartilage is specifically the smooth, white tissue covering the ends of bones where they come together to form joints. Structure of Hyaline Cartilage The matrix is mostly comprised of collagen and, in some cases, elastic fibers, embedded in a highly hydrated proteoglycan gel. Reading time: 8 minutes. – Chondrocytes-  These chondrocytes produce large amounts of extracellular matrix composed of collagen fibers, proteoglycan, and elastin fibers. It is the most widespread cartilage type and, in adults, it forms the articular surfaces of long bones, the rib tips, the rings of the trachea, and parts of the skull. Other medications aim to specifically inhibit inflammatory cytokines, such as tumor necrosis factor alpha, which helps drive inflammation in RA. It is mostly found in the infant skeleton which replaced by bone during growth. Tumors made up of cartilage tissue can also occur, but can be either benign or malignant in nature. Treatment often involves various anti-inflammatory medications, such as non-steroidal anti-inflammatory drugs (NSAIDs) like aspirin or ibuprofen, or other COX inhibitors for symptomatic relief. Collagen type II fibrils are often less than 50 nm in diameter and are too small to be seen by light microscopy. It is found in the epiglottis (part of the larynx) and the pinnae (the external ear flaps of many mammals, including humans). Copyright © Fibrocartilage. 2. Bone tissue Your email address will not be published. This causes it to heal very slowly. Cartilage, connective tissue forming the mammalian embryonic skeleton prior to bone formation and persisting in parts of the human skeleton into adulthood. It has lots of collagen fibers (Type I and Type II), and it tends to grade into the dense tendon and ligament tissue. The elasticity and flexibility of cartilage helps to maintain change of position of ear lobe during sleep. Read more. “The knee is the largest joint in the body, and relies on two knee cartilage types to function effectively: fibrocartilage and articular cartilage. This results in “bone against bone” grinding within the joint that leads to reduced range of movement, loss of proprioception, and pain. Elastic cartilage functions to provide support and maintain the shape of flexible body parts like our ears and larynx. Required fields are marked *. The main cell types in cartilage are chondrocytes, the ground substance is chondroitin sulfate, and the fibrous sheath is called perichondriu… Understanding knee cartilage types “Knee injuries are an area of focus for me, so I get questions about cartilage all the time,” says sports medicine surgeon Dr. Jack Skendzel. When a chondroblast divides, its descendants temporarily occupy the same chondroitin. Three types of cartilage(hyaline cartilage, white fibrocartilage, and yellow elastic cartilage) can be distinguished on the basis of the composition and structure of their extracellular matrices, but many features of the cells and matrix are common to all three types, and these features will be considered first. Matrix On account of being avascular (lacking blood supply), articular cartilage can get damaged due to the normal wear and tear that occurs with age or an injury. The layers of articular cartilage are defined by zones. Large proteoglycan molecules have numerous side chains of glycosaminoglycans (GAGs), carbohydrates with remarkable water-binding properties. Apposition is thought to be most prevalent in mature cartilages, but interstitial growth must persist for long periods in growth-plate cartilage. It is a progressive and chronic autoimmune disease that triggers inflammation and results in damage to joint tissue, nearby bone and other organs, therefore indirectly affecting cartilage. This zone is also the only zone where articular cartilage progenitor cells have been identified. It is made up of cells called chondrocytes which are embedded in a matrix of collagen and elastic fibers. Since osteoarthritis affects the joints exposed to the highest stress (knees, elbows, and hips), this condition is considered less of a disease and is rather regarded as a result of “wear and tear”. More powerful immune system suppressing agents such as methotrexate and cyclosporine are sometimes used. Look at the eMicroscope of a section of cartilage on the left. Embedded in this are one or two round nuclei with the usual intranuclear network. RA progresses normally from various small to larger joints of the body, and damage to hands and feet is more likely to develop before damage to larger joints such as the hips or knees. Reviewer: The collagen network varies in different types of cartilage and with age. Starting from the subchondral bone, there is a tidemark that is deep to the basal layer and separates true articular cartilage from the deeper cartilage, which is a remnant of cartilage anlage from longitudinal growth during childhood. Chondrocytes lie between the fibers. Therefore, when this ECM is affected, it can lead to damage or injury. There are three types of cartilage: Elastic cartilage (yellow cartilage) – the most springy and supple type of cartilage. The cartilage lines the ear lobe, epiglottis and larynx. It is predominately collagen (yet with few collagen fibers), and its name refers to its glassy appearance. Examples of tubes include the cricoid cartilage and carina of the trachea, the torus tubarius at the opening of the auditory tube, and the auricle/pinna of the ear. Learn more about the structure and function of cartilage. A preponderance of fixed negative charges on the surface of GAGs strongly attracts polarized water molecules, causing wet cartilage to swell until restricted by tension in the collagen network, or by external loading. It is histologically similar to hyaline cartilage but contains many yellow elastic fibers lying in a solid matrix. It is composed of a dense network of collagen fibers embedded in a gelatinous ground substance. The collagen (mainly type II), acts to constrain the proteoglycans and helps it hold its structure. Formed by the process of chondrogenesis, the resulting chondrocytes are capable of producing large amounts of collagenous extracellular matrix and ground substance, which together form cartilage itself. c) fibrocartilage. Oftentimes, many of these medications are used in combination. More typical of cartilage is collagen type II, which forms very thin fibrils dispersed between the proteoglycan molecules so that they do not clump together to form larger fibers. Learning anatomy is a massive undertaking, and we're here to help you pass with flying colours. I also engage myself in teaching which enhances my creativity and makes me more expressible. Cartilage is not hard just like bone. The length of collagen fibrils and fibers in cartilage is unknown, but even relatively short fibrils can reinforce the matrix by interacting physically and chemically with each other and with other matrix constituents including proteoglycans (Hukins and Aspden 1985), reflecting the fact that the term collagen means ‘glue maker’. The principal protein is elastin. When an embryo is developing, cartilage is the precursor to bone. Effectively, water is held in place by proteoglycans, which are themselves held in place by the collagen network. One of the main functions of this type of cartilage is to enable the bones in the joints to move and glide over each other without friction. 1. Cartilage is a robust and viscoelastic connective tissue that can be found in joints between bones, the rib cage, intervertebral discs, the ear, and the nose. – Hyaline cartilage, the most abundant type of cartilage, plays a supportive role and assists in movement. Damage or injury can also happen through pathologic states, where ossification or breakdown of cartilage occurs due to dysfunction of cartilage-specific cells or synovial cells, or imbalances in the microenvironment surrounding the cartilage. 3. Cartilage is a flexible connective tissue found in multiple areas of the body, including joints, the ear and nose, and intervertebral discs. Cartilage has limited reparative capacities for a number of reasons: Therefore, the standard treatments often involve total joint replacements (arthroplasty) or clever bioengineering techniques to regenerate articular cartilage through scaffolding and stem cell engineering. It is covered externally by a fibrous membrane, called the perichondrium, except at the articular ends of bones; it also occurs under the skin (for instance, ears and nose). Finally, there is most superficial layer, also known as the tangential zone. The main cell types in cartilage are chondrocytes, the ground substance is chondroitin sulfate, and the fibrous sheath is called perichondrium. This article will explain the structure, composition and formation of this structure. Timely treatment of cartilage damage is therefore essential. The first type is called hyaline cartilage. The calcified zone of the articular cartilage serves to bind the articular cartilage to the bone tissue by anchoring the collagen fibrils of the deep zone of the cartilage to the subchondral bone. The cells of the outer layer become fibroblasts and secrete a dense collagenous matrix lined externally by vascular mesenchyme. composed of a delicate network of fine type II collagen fibrils, type IX collagen, and proteoglycan core protein. An essential feature of the cartilage is that it has no blood vessels. Functions of Cartilage Cartilage is the only tissue that never stops growing! Kenhub. The remodeling of cartilage is predominantly affected by changes and rearrangements of the collagen matrix, which responds to tensile and compressive forces experienced by the cartilage. In yet other sites, the matrix of early cellular cartilage is permeated first by anastomosing oxytalan fibers, and later by elastin fibers. Instead of round chondrocytes, the superficial layer contains flattened chondrocytes, in addition to condensed collagen fibers and spare proteoglycans. Treatment involves arthroplasty and chondroitin sulfate or glucosamine sulfate supplements. Cartilage is a pliant, load-bearing connective tissue, covered by a fibrous perichondrium except at its junctions with bones and over the articular surfaces of synovial joints. Skeletal system – Introduction & functions of skeletal system. Finally, treatment can also involve surgery or more progressive gene therapy drugs. (adsbygoogle = window.adsbygoogle || []).push({}); It is weaker than bone, but it is flexible and can recover quickly. The continuing division produces isogenous groups. due to overuse or traumatic injury during athletics). It is harder and stronger than prior tissue types. Its growth is not usually quantified by an increase in size or mass of the cartilage itself, but instead by its biomechanical properties. • The main cell types in cartilage are chondrocytes, the ground substance is chondroitin sulfate, and the fibrous sheath is called perichondrium. 3–5 Under electron microscopy, collagen is noted to have a cross-banded fibrillar structure. There are … • Hyaline cartilage is the most widespread type and resembles glass. Most fibrous tissues contain collagen type I, which forms large fibers with a wavy ‘crimped’ structure; however, this type of collagen is only found in cartilage in the outer layers of the perichondrium and in white fibrocartilage. This continuing process adds additional surface, while the entrapped cells participate in interstitial growth. It has a perichondrium, and it is the weakest of the three types of cartilage. At some sites, continued secretion of matrix separates the cells, producing typical hyaline cartilage. They also become rounded, with prominent round or oval nuclei and a low cytoplasm: nucleus ratio. These are relatively soft and elastic or flexible. Collagen type II is found in the notochord, the nucleus pulposus of an intervertebral disc, the vitreous body of the eye, and the primary corneal stroma. The intermediate zone is adjacent to the basal layer, with an oblique or random organization of type II collagen. In all cases, developing cartilage is surrounded by condensed mesenchyme, which differentiates into a bilaminar perichondrium. While these tumors usually appear in bone, and rarely in pre-existing cartilage, they can invade cartilage. It is the only type of cartilage that contains type I collagen in addition to the normal type II. As a person ages, this cartilage can wear away, leading to joint pain and swelling that is sometimes only alleviated by surgery. Cartilage is an avascular, supporting and articular skeletal tissue consisting of cells in an extracellular matrix that may or may not mineralise depending on cartilage type, species or group of organisms; many invertebrates have cartilage but it never mineralises. Cartilages are made up of specialized cells known as chondrocytes. Cartilage is a strong, flexible type of connective tissue found within a body. While osteoarthritis is a disease that affects the whole joint, one of the most affected tissues is the articular cartilage, which is thinned or completely worn away. The most common proteoglycan molecule, aggrecan, form huge molecular aggregates with other proteoglycans and with hyaluronan. Three types of cartilage(hyaline cartilage, white fibrocartilage, and yellow elastic cartilage) can be distinguished on the basis of the composition and structure of their extracellular matrices, but many features of the cells and matrix are c… All rights reserved. White fibrocartilage consists of a mixture of white fibrous tissue and cartilaginous tissue in various proportions. There are 3 types of cartilage, namely Fibrocartilage, Hyaline and elastic cartilage. Kim Bengochea, Regis University, Denver, Author: Cartilage is a non-vascular type of supporting connective tissue that is found throughout the body . Costal cartilages that connect the ventral ends of the ribs to the sternum increases elasticity of the chest wall Arthroplasty and chondroitin sulfate or glucosamine sulfate supplements are arranged in columns cartilage itself, but by! Of chondrocytes and ECM least amount of ECM can be either benign or malignant in nature a solid matrix rapid. These chondrocytes produce large amounts of elastin and collagen packed ; the shape their... The structure and function of cartilage in the body ( unlike osteoarthritis ) and research, validated experts... 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cartilage types and functions

Elsewhere, many cells become fibroblasts; collagen synthesis predominates and chondroblastic activity appears only in isolated groups or rows of cells that become surrounded by dense bundles of collagen fibers to form white fibrocartilage. Each cell differentiates into a chondroblast as it secretes a basophilic halo of the matrix, Cartilage is usually formed in embryonic mesenchyme. The most common GAG side chains in cartilage are chondroitin sulfate and keratan sulfate. There are several diseases and processes that can affect cartilage. Due to the lack of blood vessels, cartilage cannot heal itself. Articular cartilage damage worsens over time and, if left untreated, leads to arthritis of the entire joint. There are no blood vessels in cartilage to supply the chondrocytes with nutrients. Embryonic cartilage either remains as cartilage or provides a substructure for endochondral ossification, meaning it also functions as a template for the rapid growth and development of the musculoskeletal system . Grounded on academic literature and research, validated by experts, and trusted by more than 1 million users. Cartilage is not innervated and therefore relies on diffusion to obtain nutrients. Last reviewed: August 31, 2020 Jerome Goffin Skeletal system – Introduction & functions of the skeletal system, KIDNEYS – Location, Size, Structure, Function and Organs Associated with kidneys, Microscopic Structure Of Skeleton Muscles, Sensory System-Introduction, Organs and Functions, The Urinary System-Introduction,Functions and Anatomy, Nervous system-Introduction, Types, and Function, Human Reproductive system- Formation of Gametes, Organs Overview and Function, Respiratory System – Introduction, Parts & Functions, Muscular system – Types of muscles, characteristics & functions. Embryonic cartilage either remains as cartilage or provides a substructure for endochondral ossification, meaning it also functions as a template for the rapid growth and … Introduction to the musculoskeletal system, chondrocytes are bound in lacunae and cannot migrate to damaged areas, cartilage does not have a blood supply so deposition of new ECM is very slow, damaged hyaline cartilage is often replaced by fibrocartilage scar tissue with different biomechanical properties, Articular cartilage of the elbow (sagittal view) - Paul Kim. Save my name, email, and website in this browser for the next time I comment. The cells of the inner layer contain differentiated, but mainly resting chondroblasts or prechondroblasts. Cartilage is a connective tissue found in various parts of the adult skeleton including all joints between bones and structures which is deformable as well as strong e.g. I love to write and share my words with the world. This forms 90% of collagen in the body; functions to resist tension and stretching; found in the dermis, tendons, ligaments, fibrocartilage, bones, and fascia Type II Collagen Is the main fiber type in hyaline and elastic cartilage and functions to resist tensile strain that occurs when cartilage is compressed T This basal layer also contains the highest concentration of proteoglycans, and round chondrocytes in this layer are arranged in columns. These cells are found solitary or in pairs and are densely scattered out within the matrix. Benign tumors are called chondromas, and the malignant tumors are called chondrosarcomas. Read more. Chondrogenesis is the process by which cartilage is formed from condensed mesenchymal cells expressing collagen I, III and V. This process also involves differentiation of chondroprogenitor cells secreting molecules (aggrecan and type II, IX and XI collagen) that form the extracellular matrix. Start studying Cartilage: Types, Functions, Locations, Slides. The deep, basal layer is found next, which consists of type II collagen that is perpendicular to the joint and crosses the tidemark. Cartilage is a resilient and smooth elastic tissue, rubber-like padding that covers and protects the ends of long bones at the joints and nerves.  Cartilage is a flexible connective tissue that differs from bone in several ways; it is avascular and its microarchitecture is less organized than bone. Rheumatoid arthritis (RA) is a disease process where the body’s immune system attacks synovial cells, and therefore the lining of joint capsules, which is a tough membrane that encloses joints. Cartilage. • Newly formed chondroblasts secrete matrix around themselves, creating superficial lacunae beneath the perichondrium. Additionally, a glycoprotein known as lubricin that is abundant in the superficial layer of cartilage and synovial fluid plays a major role in bio-lubrication and wear protection of cartilage. So, you can find hyaline cartilage in the larynx and trachea in the throat portion of the body, and then also in all of the joints where the surfaces of bones are articulating each other. This smooth, transparent, glassy type of cartilage coats the ends … Your email address will not be published. Our engaging videos, interactive quizzes, in-depth articles and HD atlas are here to get you top results faster. From the cartilaginous tissue a kind of hard semi-transparent organic substance is secreted which is known as *Chondrin*. This type of cartilage contains elastic fiber networks and collagen fibers. They are found on many joint surfaces. b) Elastic cartilage. Interstitial growth is the result of continued mitosis of early chondroblasts throughout the tissue mass and is obvious only in young cartilage, where the plasticity of the matrix permits continued expansion. It contains no nerves or blood vessels, and its structure is relatively simple. Hyaline cartilage is the most abundant type of cartilage in the body. Elastic cartilage has the most ECM; hyaline a middle amount; and fibrous cartilage has the least amount of ECM. This zone is the thickest layer of round chondrocytes, with abundant proteoglycan content. Transmission electron microscopy reveals that they have a characteristic cross-banding (65 nm periodicity) and are interwoven to create a three-dimensional meshwork. This causes it to heal very slowly. While more rigid and less flexible than muscle, cartilage is not as stiff as bone. In the embryo , it provides support and is a precursor to bone . Register now It has a capacity for rapid interstitial and appositional growth in young and growing tissues. If a thin slice of cartilage is examined under the microscope, it will be found to consist of cells of a rounded or bluntly angular form, lying in groups of two or more in a granular or almost homogeneous matrix. As mentioned before, the ECM is paramount in opposing shear, tensile, and compressive forces normally. These cells have generally straight outlines where they are in contact with each other, with the rest of their circumference rounded. from IGNOU and have completed a Diploma in Medical Laboratory Technology from Young Women Christian Association (YWCA) institute. Other constituents of cartilage include dissolved salts, non-collagenous proteins, and glycoproteins. Three α chains intertwine into a triple helix, forming a procollagen molecule. The collagen of articular cartilage is primarily type II (90–95%), with small contributions from types IX and XI. Cartilage function is more than structural, and has different functions in the life cycle. Healthy articular cartilage allows joints to move and glide over each other with very little friction, but is subject to damage and injury, as well as normal wear and tear. It is a different form of connective tissue. It owes its flexibility and toughness to the fibrous tissue and its elasticity to the cartilaginous tissue. and grab your free ultimate anatomy study guide! It works just like a cushion in the joints. –  There are two types of which are the following: – Chondroblast – It is a type of cell that develops into a chondrocyte or cartilage cell. “I would honestly say that Kenhub cut my study time in half.” Fibrocartilage is found in the pubic symphysis, the annulus fibrosus of intervertebral discs, menisci, and the temporal-mandibular joint. Hyaline cartilage, the most abundant type of cartilage, plays a supportive role and assists in movement. the elbows, knees, and ankles, ends of the ribs, Between the vertebrae in the spine, ears, and nose, Bronchial tubes or airways. Articular cartilage is specifically the smooth, white tissue covering the ends of bones where they come together to form joints. Structure of Hyaline Cartilage The matrix is mostly comprised of collagen and, in some cases, elastic fibers, embedded in a highly hydrated proteoglycan gel. Reading time: 8 minutes. – Chondrocytes-  These chondrocytes produce large amounts of extracellular matrix composed of collagen fibers, proteoglycan, and elastin fibers. It is the most widespread cartilage type and, in adults, it forms the articular surfaces of long bones, the rib tips, the rings of the trachea, and parts of the skull. Other medications aim to specifically inhibit inflammatory cytokines, such as tumor necrosis factor alpha, which helps drive inflammation in RA. It is mostly found in the infant skeleton which replaced by bone during growth. Tumors made up of cartilage tissue can also occur, but can be either benign or malignant in nature. Treatment often involves various anti-inflammatory medications, such as non-steroidal anti-inflammatory drugs (NSAIDs) like aspirin or ibuprofen, or other COX inhibitors for symptomatic relief. Collagen type II fibrils are often less than 50 nm in diameter and are too small to be seen by light microscopy. It is found in the epiglottis (part of the larynx) and the pinnae (the external ear flaps of many mammals, including humans). Copyright © Fibrocartilage. 2. Bone tissue Your email address will not be published. This causes it to heal very slowly. Cartilage, connective tissue forming the mammalian embryonic skeleton prior to bone formation and persisting in parts of the human skeleton into adulthood. It has lots of collagen fibers (Type I and Type II), and it tends to grade into the dense tendon and ligament tissue. The elasticity and flexibility of cartilage helps to maintain change of position of ear lobe during sleep. Read more. “The knee is the largest joint in the body, and relies on two knee cartilage types to function effectively: fibrocartilage and articular cartilage. This results in “bone against bone” grinding within the joint that leads to reduced range of movement, loss of proprioception, and pain. Elastic cartilage functions to provide support and maintain the shape of flexible body parts like our ears and larynx. Required fields are marked *. The main cell types in cartilage are chondrocytes, the ground substance is chondroitin sulfate, and the fibrous sheath is called perichondriu… Understanding knee cartilage types “Knee injuries are an area of focus for me, so I get questions about cartilage all the time,” says sports medicine surgeon Dr. Jack Skendzel. When a chondroblast divides, its descendants temporarily occupy the same chondroitin. Three types of cartilage(hyaline cartilage, white fibrocartilage, and yellow elastic cartilage) can be distinguished on the basis of the composition and structure of their extracellular matrices, but many features of the cells and matrix are common to all three types, and these features will be considered first. Matrix On account of being avascular (lacking blood supply), articular cartilage can get damaged due to the normal wear and tear that occurs with age or an injury. The layers of articular cartilage are defined by zones. Large proteoglycan molecules have numerous side chains of glycosaminoglycans (GAGs), carbohydrates with remarkable water-binding properties. Apposition is thought to be most prevalent in mature cartilages, but interstitial growth must persist for long periods in growth-plate cartilage. It is a progressive and chronic autoimmune disease that triggers inflammation and results in damage to joint tissue, nearby bone and other organs, therefore indirectly affecting cartilage. This zone is also the only zone where articular cartilage progenitor cells have been identified. It is made up of cells called chondrocytes which are embedded in a matrix of collagen and elastic fibers. Since osteoarthritis affects the joints exposed to the highest stress (knees, elbows, and hips), this condition is considered less of a disease and is rather regarded as a result of “wear and tear”. More powerful immune system suppressing agents such as methotrexate and cyclosporine are sometimes used. Look at the eMicroscope of a section of cartilage on the left. Embedded in this are one or two round nuclei with the usual intranuclear network. RA progresses normally from various small to larger joints of the body, and damage to hands and feet is more likely to develop before damage to larger joints such as the hips or knees. Reviewer: The collagen network varies in different types of cartilage and with age. Starting from the subchondral bone, there is a tidemark that is deep to the basal layer and separates true articular cartilage from the deeper cartilage, which is a remnant of cartilage anlage from longitudinal growth during childhood. Chondrocytes lie between the fibers. Therefore, when this ECM is affected, it can lead to damage or injury. There are three types of cartilage: Elastic cartilage (yellow cartilage) – the most springy and supple type of cartilage. The cartilage lines the ear lobe, epiglottis and larynx. It is predominately collagen (yet with few collagen fibers), and its name refers to its glassy appearance. Examples of tubes include the cricoid cartilage and carina of the trachea, the torus tubarius at the opening of the auditory tube, and the auricle/pinna of the ear. Learn more about the structure and function of cartilage. A preponderance of fixed negative charges on the surface of GAGs strongly attracts polarized water molecules, causing wet cartilage to swell until restricted by tension in the collagen network, or by external loading. It is histologically similar to hyaline cartilage but contains many yellow elastic fibers lying in a solid matrix. It is composed of a dense network of collagen fibers embedded in a gelatinous ground substance. The collagen (mainly type II), acts to constrain the proteoglycans and helps it hold its structure. Formed by the process of chondrogenesis, the resulting chondrocytes are capable of producing large amounts of collagenous extracellular matrix and ground substance, which together form cartilage itself. c) fibrocartilage. Oftentimes, many of these medications are used in combination. More typical of cartilage is collagen type II, which forms very thin fibrils dispersed between the proteoglycan molecules so that they do not clump together to form larger fibers. Learning anatomy is a massive undertaking, and we're here to help you pass with flying colours. I also engage myself in teaching which enhances my creativity and makes me more expressible. Cartilage is not hard just like bone. The length of collagen fibrils and fibers in cartilage is unknown, but even relatively short fibrils can reinforce the matrix by interacting physically and chemically with each other and with other matrix constituents including proteoglycans (Hukins and Aspden 1985), reflecting the fact that the term collagen means ‘glue maker’. The principal protein is elastin. When an embryo is developing, cartilage is the precursor to bone. Effectively, water is held in place by proteoglycans, which are themselves held in place by the collagen network. One of the main functions of this type of cartilage is to enable the bones in the joints to move and glide over each other without friction. 1. Cartilage is a robust and viscoelastic connective tissue that can be found in joints between bones, the rib cage, intervertebral discs, the ear, and the nose. – Hyaline cartilage, the most abundant type of cartilage, plays a supportive role and assists in movement. Damage or injury can also happen through pathologic states, where ossification or breakdown of cartilage occurs due to dysfunction of cartilage-specific cells or synovial cells, or imbalances in the microenvironment surrounding the cartilage. 3. Cartilage is a flexible connective tissue found in multiple areas of the body, including joints, the ear and nose, and intervertebral discs. Cartilage has limited reparative capacities for a number of reasons: Therefore, the standard treatments often involve total joint replacements (arthroplasty) or clever bioengineering techniques to regenerate articular cartilage through scaffolding and stem cell engineering. It is covered externally by a fibrous membrane, called the perichondrium, except at the articular ends of bones; it also occurs under the skin (for instance, ears and nose). Finally, there is most superficial layer, also known as the tangential zone. The main cell types in cartilage are chondrocytes, the ground substance is chondroitin sulfate, and the fibrous sheath is called perichondrium. This article will explain the structure, composition and formation of this structure. Timely treatment of cartilage damage is therefore essential. The first type is called hyaline cartilage. The calcified zone of the articular cartilage serves to bind the articular cartilage to the bone tissue by anchoring the collagen fibrils of the deep zone of the cartilage to the subchondral bone. The cells of the outer layer become fibroblasts and secrete a dense collagenous matrix lined externally by vascular mesenchyme. composed of a delicate network of fine type II collagen fibrils, type IX collagen, and proteoglycan core protein. An essential feature of the cartilage is that it has no blood vessels. Functions of Cartilage Cartilage is the only tissue that never stops growing! Kenhub. The remodeling of cartilage is predominantly affected by changes and rearrangements of the collagen matrix, which responds to tensile and compressive forces experienced by the cartilage. In yet other sites, the matrix of early cellular cartilage is permeated first by anastomosing oxytalan fibers, and later by elastin fibers. Instead of round chondrocytes, the superficial layer contains flattened chondrocytes, in addition to condensed collagen fibers and spare proteoglycans. Treatment involves arthroplasty and chondroitin sulfate or glucosamine sulfate supplements. Cartilage is a pliant, load-bearing connective tissue, covered by a fibrous perichondrium except at its junctions with bones and over the articular surfaces of synovial joints. Skeletal system – Introduction & functions of skeletal system. Finally, treatment can also involve surgery or more progressive gene therapy drugs. (adsbygoogle = window.adsbygoogle || []).push({}); It is weaker than bone, but it is flexible and can recover quickly. The continuing division produces isogenous groups. due to overuse or traumatic injury during athletics). It is harder and stronger than prior tissue types. Its growth is not usually quantified by an increase in size or mass of the cartilage itself, but instead by its biomechanical properties. • The main cell types in cartilage are chondrocytes, the ground substance is chondroitin sulfate, and the fibrous sheath is called perichondrium. 3–5 Under electron microscopy, collagen is noted to have a cross-banded fibrillar structure. There are … • Hyaline cartilage is the most widespread type and resembles glass. Most fibrous tissues contain collagen type I, which forms large fibers with a wavy ‘crimped’ structure; however, this type of collagen is only found in cartilage in the outer layers of the perichondrium and in white fibrocartilage. This continuing process adds additional surface, while the entrapped cells participate in interstitial growth. It has a perichondrium, and it is the weakest of the three types of cartilage. At some sites, continued secretion of matrix separates the cells, producing typical hyaline cartilage. They also become rounded, with prominent round or oval nuclei and a low cytoplasm: nucleus ratio. These are relatively soft and elastic or flexible. Collagen type II is found in the notochord, the nucleus pulposus of an intervertebral disc, the vitreous body of the eye, and the primary corneal stroma. The intermediate zone is adjacent to the basal layer, with an oblique or random organization of type II collagen. In all cases, developing cartilage is surrounded by condensed mesenchyme, which differentiates into a bilaminar perichondrium. While these tumors usually appear in bone, and rarely in pre-existing cartilage, they can invade cartilage. It is the only type of cartilage that contains type I collagen in addition to the normal type II. As a person ages, this cartilage can wear away, leading to joint pain and swelling that is sometimes only alleviated by surgery. Cartilage is an avascular, supporting and articular skeletal tissue consisting of cells in an extracellular matrix that may or may not mineralise depending on cartilage type, species or group of organisms; many invertebrates have cartilage but it never mineralises. Cartilages are made up of specialized cells known as chondrocytes. Cartilage is a strong, flexible type of connective tissue found within a body. While osteoarthritis is a disease that affects the whole joint, one of the most affected tissues is the articular cartilage, which is thinned or completely worn away. The most common proteoglycan molecule, aggrecan, form huge molecular aggregates with other proteoglycans and with hyaluronan. 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