Cartilage

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Cartilage

Cartilage is a type of dense connective tissue

Connective tissue

Connective tissue is a form of fibrous biological tissue.It is one of the four types of tissue in traditional classifications .Collagen is the main protein of connective tissue in animals and the most abundant protein in mammals, making up about 25% of the total protein content....
. It is composed of specialized cells called chondrocytes

Chondrocyte

Chondrocytes are the only cells found in cartilage. They produce and maintain the cartilaginous matrix, which consists mainly of collagen and proteoglycans....
that produce a large amount of extracellular matrix

Extracellular matrix

In biology, the extracellular matrix is the extracellular part of animal tissue that usually provides structural support to the animal Cell in addition to performing various other important functions....
composed of collagen

Collagen

Collagen is the main protein of connective tissue in animals and the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content....
fibers, abundant ground substance

Ground substance

Ground substance is a term for the non-cellular components of extracellular matrix containing the fibers.It is usually not visible on slides, because it is removed during the preparation process....
rich in proteoglycan

Proteoglycan

File:PBB Protein ACAN image.jpgProteoglycans represent a special class of glycoproteins that are heavily glycosylation. They consist of a core protein with one or more covalent bond attached glycosaminoglycan chain....
, and elastin

Elastin

Elastin is a protein in connective tissue that is Elasticity and allows many tissues in the body to resume their shape after stretching or contracting....
fibers. Cartilage is classified in three types, elastic cartilage, hyaline cartilage and fibrocartilage, which differ in the relative amounts of these three main components.

Cartilage is found in many areas in the body including the articular surface of the bones

Bone

Bones are rigid organ that form part of the endoskeleton of vertebrates. They function to move, support, and protect the various organs of the body, produce red blood cell and white blood cells and store minerals....
, the rib cage, the ear

Ear

The ear is the sense organ that detects sounds. The vertebrate ear shows a common biology from fish to humans, with variations in structure according to order and species....
, the nose

Nose

Anatomically, a nose is a protuberance in vertebrates that houses the nostrils, or nares, which admit and expel air for Respiration in conjunction with the mouth....
, the bronchial tubes and the intervertebral disc

Intervertebral disc

Intervertebral discs lie between adjacent vertebra in the vertebral column. Each disc forms a cartilaginous joint to allow slight movement of the vertebrae, and acts as a ligament to hold the vertebrae together....
s.

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Encyclopedia

Cartilage is a type of dense connective tissue

Connective tissue

Chondrocyte

Extracellular matrix

Collagen

Ground substance

Proteoglycan

Elastin

Bone

Ear

The ear is the sense organ that detects sounds. The vertebrate ear shows a common biology from fish to humans, with variations in structure according to order and species....
, the nose

Nose

Intervertebral disc

Bone

Tendon

A tendon is a tough band of fibrous connective tissue that usually connects muscle to bone and is capable of withstanding tension . Tendons are similar to ligaments except that ligaments join one bone to another....
.

Unlike other connective tissues, cartilage does not contain blood vessels. The chondrocytes are fed by diffusion, helped by the pumping action generated by compression of the articular cartilage or flexion of the elastic cartilage. Thus, compared to other connective tissues, cartilage grows and repairs more slowly.

Types of cartilage

Hyaline cartilage

Hyaline cartilage consists of a slimy mass of a firm consistency, but of considerable elasticity and pearly bluish color. It contains no nerves or blood vessels, and its structure is relatively simple....
is a rather hard, translucent material rich in collagen and proteoglycan. It covers the end of bone to form the smooth articular surface of joints

Joint

A joint is the location at which two or more bones make contact. They are constructed to allow movement and provide mechanical support, and are classified structurally and functionally....
. It is also found in the nose

Nose

Anatomically, a nose is a protuberance in vertebrates that houses the nostrils, or nares, which admit and expel air for Respiration in conjunction with the mouth....
, the larynx

Larynx

The larynx , colloquially known as the voicebox, is an organ in the neck of mammals involved in protection of the vertebrate trachea and sound production....
and between the ribs

Rib

In vertebrate anatomy, ribs are the long curved bones which form the ribcage. In most vertebrates, ribs surround the chest and protect the lungs, heart, and other internal Organ s of the thorax....
and the sternum

Sternum

The sternum is a long flat bone located in the center of the chest . It connects to the rib via cartilage, forming the rib cage with them, and thus helps to protect the lungs, heart and major blood vessels from physical trauma....
. Bones grow via a hyaline cartilage intermediate, a process called Endochondral ossification

Endochondral ossification

Endochondral ossification is one of the two processes during fetal development of the mammal skeleton in which bone tissue is created. It is also an essential process during the rudimentary formation of long bones, the growth of the Epiphyseal plate of long bones, and the healing of bone healing....
.hyaline cartilage has no visible fibers under light microscope. It is due to 1-refractive index of fibers and matrix is nearly same 2-fibers are small in size cells are present in lacunae!

Elastic cartilage

Elastic cartilage or yellow cartilage is a type of cartilage present in the outer ear, larynx, and epiglottis. It contains elastic fiber networks and collagen fibers....
contains large amounts of elastic fibers (elastin

Elastin

Elastin is a protein in connective tissue that is Elasticity and allows many tissues in the body to resume their shape after stretching or contracting....
) scattered throughout the matrix. It is stiff yet elastic, and is important to prevent tubular structures from collapsing. Elastic cartilage is found in the pinna of the ear, in tubular structures such as the auditory (Eustachian

Eustachian tube

The Eustachian tube is a tube that links the pharynx to the middle ear. In adults the Eustachian tube is approximately 35 mm long. It is named after the sixteenth century anatomist Bartolomeo Eustachi....
) tubes and in the epiglottis

Epiglottis

The epiglottis is a flap of elastic cartilage tissue covered with a mucous membrane, attached to the root of the tongue. It projects obliquely upwards behind the tongue and the hyoid bone....
.

Fibrocartilage

White fibrocartilage consists of a mixture of white fibrous tissue and cartilaginous tissue in various proportions; to the former of these constituents it owes its flexibility and toughness, and to the latter its elasticity....
is characterized by a dense network of Type I collagen. It is a white, very tough material that provides high tensile strength and support. It contains more collagen and less proteoglycan than hyaline cartilage. Thus, its properties are closer to those of tendons than hyaline cartilage. It is present in areas most subject to frequent stress like intervertebral discs, the symphysis pubis and the attachments of certain tendons and ligaments.

Growth and development

In embryogenesis

Embryogenesis

Embryogenesis is the process by which the embryo is formed and develops. It starts with the fertilization of the ovum, egg, which, after fertilization, is then called a zygote....
, the skeletal system is derived from the mesoderm

Germ layer

A germ layer is a group of cell s, formed during animal embryogenesis. Germ layers are particularly pronounced in the vertebrates; however, all animals more complex than sea sponge produce two or three primary tissue layers ....
germ layer. Chondrification (also known as chondrogenesis) is the process by which cartilage is formed from condensed mesenchyme

Mesenchyme

Mesenchyme is a type of loose connective tissue, of mesodermal origin and located within the embryo mesoderm, consisting of a ground substance Matrix containing a loose aggregate of unspecialized cell which are capable of developing into connective tissue, bone, cartilage, the lymphatic system, and the circulatory system....
tissue, which differentiates into chondrocytes and begins secreting the molecules that form the extracellular matrix.

Diseases and treatment

There are several diseases which can affect the cartilage. Chondrodystrophies are a group of diseases characterized by disturbance of growth and subsequent ossification

Ossification

Ossification is the process of bone formation, in which connective tissues, such as cartilage are turned to bone or bone-like tissue. The ossified tissue is invaginated with blood vessels....
of cartilage. Some common diseases affecting/involving the cartilage are listed below.

Osteoarthritis
Osteoarthritis

Osteoarthritis , is a group of diseases and mechanical abnormalities entailing degradation of joints, including articular cartilage and the subchondral bone next to it....
: The cartilage covering bones (articular cartilage) is thinned, eventually completely worn out, resulting in a "bone against bone" joint, reduced motion and pain. Osteoarthritis is very common, affects the joints exposed to high stress and is therefore considered the result of "wear and tear" rather than a true disease. It is treated by Arthroplasty
Arthroplasty

Arthroplasty is an operative procedure of Podiatric surgery performed, in which the arthritic or dysfunctional joint surface is replaced with something better or by remodeling or realigning the joint by osteotomy or some other procedure....
, the replacement of the joint by a synthetic joint often made of a Stainless Steel alloy (cobalt chromoly) and High Molecular Weight Polyethylene (HMWPE). Chondroitin sulfate
Chondroitin sulfate

Chondroitin sulfate is a sulfated glycosaminoglycan composed of a chain of alternating sugars . It is usually found attached to proteins as part of a proteoglycan....
, a monomer of the polysaccharide portion of proteoglycan
Proteoglycan

File:PBB Protein ACAN image.jpgProteoglycans represent a special class of glycoproteins that are heavily glycosylation. They consist of a core protein with one or more covalent bond attached glycosaminoglycan chain....
, has been shown to reduce the symptoms of osteoarthritis, possibly by increasing the synthesis of the extracellular matrix.
Traumatic rupture or detachment: The cartilage in the knee
Knee

----The knee is the lower extremity joint connecting the femur, patella, and the tibia and the surrounding anatomical region which includes the popliteal fossa, also known as "knee pit"....
is frequently damaged, and can be partially repaired through knee cartilage replacement therapy
Knee cartilage replacement therapy

Articular cartilage, most notably that which is found in the knee joint, is generally characterized by very low friction, high wear resistance, and poor regenerative qualities....
Achondroplasia
Achondroplasia

Achondroplasia dwarfism is a type of autosomal Dominance genetic disorder that is a common cause of dwarfism. Achondroplastic dwarfs have short stature, with an average adult height of 131 centimeter for males and 123 cm for females....
: Reduced proliferation of chondrocytes in the epiphyseal plate of long bones during infancy and childhood, resulting in dwarfism
Dwarfism

Dwarfism is a medical term describing a person of short stature, with the most widely accepted definition of a dwarf being a person with an adult height of less than 4 feet 10 inches ....
.
Costochondritis: Inflammation of cartilage in the ribs, causing chest pain
Chest pain

In medicine, chest pain is a symptom of a number of serious conditions and is generally considered a medical emergency. Even though it may be determined that the chest pain is non-cardiac in origin this is often a diagnosis of exclusion made after ruling out more serious causes of pain....
.
Spinal disc herniation
Spinal disc herniation

A spinal disc herniation ', incorrectly called a "slipped disc", is a medical condition affecting the Vertebral column, in which a tear in the outer, fibrous ring of an intervertebral disc ' allows the soft, central portion to hernia....
: Asymmetrical compression of an intervertebral disc
Intervertebral disc

Intervertebral discs lie between adjacent vertebra in the vertebral column. Each disc forms a cartilaginous joint to allow slight movement of the vertebrae, and acts as a ligament to hold the vertebrae together....
ruptures the sac-like disc, causing a herniation
Hernia

A hernia is a wiktionary:protrusion of a Biological tissue, structure, or part of an organ through the muscle tissue or the biological membrane by which it is normally contained....
of its soft content. The hernia often compresses the adjacent nerves and causes back pain.
Relapsing polychondritis: a destruction, probably autoimmune
Autoimmunity

Autoimmunity is the failure of an organism to recognize its own constituent parts as self, which results in an immune response against its own cells and tissues....
, of cartilage, especially of the nose and ears, causing disfiguration. Death occurs by suffocation
Suffocation

Suffocation is the process of being Asphyxia.It may also refer to:* Suffocation , a brutal death metal band.* Suffocate, a song by the post-grunge band Finger Eleven from their 2000 album The Greyest of Blue Skies....
as the larynx loses its rigidity and collapses.

Tumors

Tumor

A tumor or tumour is the name for a swelling or lesion formed by an abnormal growth of cells . Tumor is not synonymous with cancer. A tumor can be Benign neoplasm, Carcinoma in situ or malignant, whereas cancer is by definition malignant....
made up of cartilage tissue, either benign or malignant

Cancer

Cancer is a class of diseases in which a group of cell display uncontrolled growth , invasion , and sometimes metastasis . These three malignant properties of cancers differentiate them from benign tumors, which are self-limited, do not invade or metastasize....
, can occur. They usually appear in bone, rarely in pre-existing cartilage. The benign tumors are called chondroma

Chondroma

A chondroma is a benign cartilaginous tumor, which is encapsulated with a lobular growing pattern.Tumor cells resemble normal cells and produce the cartilaginous matrix ....
, the malignant ones chondrosarcoma

Chondrosarcoma

A chondrosarcoma is a type of cancer of the bone. Chondrosarcoma is a cartilage-based tumor and is in a category of cancers called sarcomas. About 25% of primary bone cancers are chondrosarcomas....
. Tumors arising from other tissues may also produce a cartilage-like matrix, the best known being pleomorphic adenoma

Pleomorphic adenoma

Pleomorphic adenoma is a benign neoplastic tumor of the salivary glands. It is the most common type of salivary gland tumor and the most common tumor of the parotid gland....
of the salivary glands.

The matrix of cartilage acts as a barrier, preventing the entry of lymphocytes or diffusion of immunoglobulins. This property allows for the transplantation

Organ transplant

Organ transplant is the moving of an organ from one body to another , for the purpose of replacing the recipient's damaged or failing organ with a working one from the donor site....
of cartilage from one individual to another without fear of tissue rejection.

Repair

Cartilage has limited repair capabilities, because chondrocytes are bound in lacunae

Lacuna (histology)

In histology, a lacuna is a small space containing an osteocyte in bone or chondrocyte in cartilage....
, they cannot migrate to damaged areas. Therefore if damaged

Articular cartilage damage

Cartilage structures and functions can be damaged. Such damage can result from a variety of causes, resulting from a bad fall or sport-accident , previous knee injuries or wear and tear over time....
, it is difficult to heal. Also, because hyaline cartilage does not have a blood supply, the deposition of new matrix is slow. Damaged hyaline cartilage is usually replaced by fibrocartilage scar tissue. Over the last years, surgeons and scientist have elaborated a series of cartilage repair procedures

Articular cartilage repair

The aim of an articular cartilage repair treatment is to restore the surface of an articular joint's hyaline cartilage. Over the last decades, surgeons and researchers have been working hard to elaborate surgical cartilage repair interventions....
that help to postpone the need for joint replacement..

Bioengineering

Bioengineering

Bioengineering is the application of engineering principles to address challenges in the fields of biology and medicine. As a study, it encompasses biomedical engineering and it is related to biotechnology....
techniques are being developed to generate new cartilage, using a cellular "scaffolding" material and cultured cells

Autologous chondrocyte implantation

Autologous Chondrocyte Implantation is a biomedical treatment that repairs damages in articular cartilage. ACI provides pain relief while at the same time slowing down the progression or considerably delaying partial or total joint replacement surgery....
to grow artificial cartilage

Cartilage in animals

Cartilaginous fish

Cartilaginous fish (chondrichthyes)

Chondrichthyes

Chondrichthyes or cartilaginous fishes are jawed fish with paired Fins, paired nares, scales, two-chambered hearts, and skeletons made of cartilage rather than bone....
like sharks

Shark

Sharks are a type of fish with a full Cartilage skeleton and a highly Streamlines, streaklines and pathlinesd body. They respire with the use of five to seven gill slits....
, rays

Ray

Ray may refer to:*Batoidea , a superorder of cartilaginous fishes**Rajiformes, "True rays" and skates*Radiation*Ray , idealized narrow beam of light...
and skates

Skate

Skates are Chondrichthyes belonging to the family Rajidae in the superorder Batoidea of rays. There are more than 200 described species in 25 genera....
have a skeleton composed entirely of cartilage. Shark cartilage

Shark cartilage

Shark cartilage, the tough material that a sharks' skeleton is composed of, is dried and powdered to create this popular dietary supplement. Shark cartilage is claimed to combat and/or prevent a variety of illnesses, most notably cancer....
is a popular but unproven dietary supplement.

Invertebrate cartilage

Cartilage tissue can also be found among invertebrates such as horseshoe crab

Horseshoe crab

The horseshoe crab or Atlantic horseshoe crab is a marine chelicerate arthropod. Despite its name, it is more closely related to spiders, ticks, and scorpions than to crabs....
s, marine snail

Snail

The word snail is a common name for almost all members of the molluscan class Gastropoda that have coiled animal shells in the adult stage. When the word snail is used in a general sense, it includes sea snails, land snails and freshwater snails....
s, and cephalopod

Cephalopod

The cephalopods are the mollusc class Cephalopoda characterized by bilateral symmetry, a prominent head, and a modification of the mollusk foot, a muscular hydrostat, into the form of cephalopod arms or tentacles....
s.

External links

University of Kansas Medical Center
Public domain
Public domain

File:PD-icon.svgThe public domain is a range of abstract materials?commonly referred to as intellectual property?which are not owned or controlled by anyone....
- Information on Articular Cartilage Injury Prevention, Repair and Rehabilitation

Cartilage

Types of cartilage

Hyaline cartilage

Elastic cartilage

Fibrocartilage

Growth and development

Diseases and treatment

Repair

Cartilage in animals

Cartilaginous fish

Invertebrate cartilage

See also

External links