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Cartilaginous
Cartilage is a resilient and smooth type of connective tissue. Semi-transparent and non-porous, it is usually covered by a tough and fibrous membrane called perichondrium. In tetrapods, it covers and protects the ends of long bones at the joints as articular cartilage, and is a structural component of many body parts including the rib cage, the neck and the bronchial tubes, and the intervertebral discs. In other taxa, such as chondrichthyans and cyclostomes, it constitutes a much greater proportion of the skeleton. It is not as hard and rigid as bone, but it is much stiffer and much less flexible than muscle. The matrix of cartilage is made up of glycosaminoglycans, proteoglycans, collagen fibers and, sometimes, elastin. It usually grows quicker than bone. Because of its rigidity, cartilage often serves the purpose of holding tubes open in the body. Examples include the rings of the trachea, such as the cricoid cartilage and carina. Cartilage is composed of specialized cell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chondrichthyes
Chondrichthyes (; ) is a class of jawed fish that contains the cartilaginous fish or chondrichthyans, which all have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or ''bony fish'', which have skeletons primarily composed of bone tissue. Chondrichthyes are aquatic vertebrates with paired fins, paired nares, placoid scales, conus arteriosus in the heart, and a lack of opercula and swim bladders. Within the infraphylum Gnathostomata, cartilaginous fishes are distinct from all other jawed vertebrates. The class is divided into two subclasses: Elasmobranchii (sharks, rays, skates and sawfish) and Holocephali ( chimaeras, sometimes called ghost sharks, which are sometimes separated into their own class). Extant chondrichthyans range in size from the finless sleeper ray to the over whale shark. Anatomy Skeleton The skeleton is cartilaginous. The notochord is gradually replaced by a vertebral column during development, e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joint
A joint or articulation (or articular surface) is the connection made between bones, ossicles, or other hard structures in the body which link an animal's skeletal system into a functional whole.Saladin, Ken. Anatomy & Physiology. 7th ed. McGraw-Hill Connect. Webp.274/ref> They are constructed to allow for different degrees and types of movement. Some joints, such as the knee, elbow, and shoulder, are self-lubricating, almost frictionless, and are able to withstand compression and maintain heavy loads while still executing smooth and precise movements. Other joints such as suture (joint), sutures between the bones of the skull permit very little movement (only during birth) in order to protect the brain and the sense organs. The connection between a tooth and the jawbone is also called a joint, and is described as a fibrous joint known as a gomphosis. Joints are classified both structurally and functionally. Joints play a vital role in the human body, contributing to movement, sta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meniscus (anatomy)
A meniscus (: menisci or meniscuses) is a crescent-shaped fibrocartilage, fibrocartilaginous anatomy, anatomical structure that, in contrast to an articular disc, only partly divides a synovial joint#Structure, joint cavity.Platzer (2004), p 208 In humans, they are present in the knee, wrist, acromioclavicular joint, acromioclavicular, sternoclavicular joint, sternoclavicular, and temporomandibular joints; in other animals they may be present in other joints. Generally, the term "meniscus" is used to refer to the cartilage of the knee, either to the lateral meniscus, lateral or medial meniscus. Both are Cartilaginous#Fibrocartilage, cartilaginous tissues that provide structural integrity to the knee when it undergoes tension (mechanics), tension and torsion (mechanics), torsion. The menisci are also known as "semi-lunar" cartilages, referring to their half-moon, crescent shape. The term "meniscus" is from the Ancient Greek word (), meaning "crescent". Structure The menisci of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intervertebral Disc
An intervertebral disc (British English), also spelled intervertebral disk (American English), lies between adjacent vertebrae in the vertebral column. Each disc forms a fibrocartilaginous joint (a symphysis), to allow slight movement of the vertebrae, to act as a ligament to hold the vertebrae together, and to function as a shock absorber for the spine. Structure Intervertebral discs consist of an outer fibrous ring, the ''anulus (or annulus) fibrosus disci intervertebralis'', which surrounds an inner gel-like center, the ''nucleus pulposus''. The ''anulus fibrosus'' consists of several layers (laminae) of fibrocartilage made up of both type I and type II collagen. Type I is concentrated toward the edge of the ring, where it provides greater strength. The stiff laminae can withstand compressive forces. The fibrous intervertebral disc contains the ''nucleus pulposus'' and this helps to distribute pressure evenly across the disc. This prevents the development of stress conc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rib Cage
The rib cage or thoracic cage is an endoskeletal enclosure in the thorax of most vertebrates that comprises the ribs, vertebral column and sternum, which protect the vital organs of the thoracic cavity, such as the heart, lungs and great vessels and support the shoulder girdle to form the core part of the axial skeleton. A typical human thoracic cage consists of 12 pairs of ribs and the adjoining costal cartilages, the sternum (along with the manubrium and xiphoid process), and the 12 thoracic vertebrae articulating with the ribs. The thoracic cage also provides attachments for extrinsic skeletal muscles of the neck, upper limbs, upper abdomen and back, and together with the overlying skin and associated fascia and muscles, makes up the thoracic wall. In tetrapods, the rib cage intrinsically holds the muscles of respiration ( diaphragm, intercostal muscles, etc.) that are crucial for active inhalation and forced exhalation, and therefore has a major ventilatory fu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fibrocartilage
Fibrocartilage consists of a mixture of white fibrous tissue and cartilaginous tissue in various proportions. It owes its inflexibility and toughness to the former of these constituents, and its elasticity to the latter. It is the only type of cartilage that contains type I collagen in addition to the normal type II. Structure The extracellular matrix of fibrocartilage is mainly made from type I collagen secreted by chondroblasts. Locations of fibrocartilage in the human body * secondary cartilaginous joints: ** pubic symphysis ** annulus fibrosis of intervertebral discs ** manubriosternal joint * glenoid labrum of shoulder joint * acetabular labrum of hip joint * medial and lateral menisci of the knee joint * location where tendons and ligaments attach to bone * triangular fibrocartilage complex (UTFCC) Function Repair If hyaline cartilage is torn all the way down to the bone, the blood supply from inside the bone is sometimes enough to start some heal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bone
A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, and enable mobility. Bones come in a variety of shapes and sizes and have complex internal and external structures. They are lightweight yet strong and hard and serve multiple functions. Bone tissue (osseous tissue), which is also called bone in the uncountable sense of that word, is hard tissue, a type of specialised connective tissue. It has a honeycomb-like matrix internally, which helps to give the bone rigidity. Bone tissue is made up of different types of bone cells. Osteoblasts and osteocytes are involved in the formation and mineralisation of bone; osteoclasts are involved in the resorption of bone tissue. Modified (flattened) osteoblasts become the lining cells that form a protective layer on the bone surface. The mine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chondrocyte
Chondrocytes (, ) are the only cells found in healthy cartilage. They produce and maintain the cartilaginous matrix, which consists mainly of collagen and proteoglycans. Although the word '' chondroblast'' is commonly used to describe an immature chondrocyte, the term is imprecise, since the progenitor of chondrocytes (which are mesenchymal stem cells) can differentiate into various cell types, including osteoblasts. Development From least- to terminally-differentiated, the chondrocytic lineage is: # Colony-forming unit-fibroblast # Mesenchymal stem cell / marrow stromal cell # Chondrocyte # Hypertrophic chondrocyte Mesenchymal (mesoderm origin) stem cells are undifferentiated, meaning they can differentiate into a variety of generative cells commonly known as osteochondrogenic (or osteogenic, chondrogenic, osteoprogenitor, etc.) cells. When referring to bone, or in this case cartilage, the originally undifferentiated mesenchymal stem cells lose their pluripotency, proliferate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extracellular Matrix
In biology, the extracellular matrix (ECM), also called intercellular matrix (ICM), is a network consisting of extracellular macromolecules and minerals, such as collagen, enzymes, glycoproteins and hydroxyapatite that provide structural and biochemical support to surrounding cells. Because multicellularity evolved independently in different multicellular lineages, the composition of ECM varies between multicellular structures; however, cell adhesion, cell-to-cell communication and differentiation are common functions of the ECM. The animal extracellular matrix includes the interstitial matrix and the basement membrane. Interstitial matrix is present between various animal cells (i.e., in the intercellular spaces). Gels of polysaccharides and fibrous proteins fill the interstitial space and act as a compression buffer against the stress placed on the ECM. Basement membranes are sheet-like depositions of ECM on which various epithelial cells rest. Each type of connective tissue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carina Of Trachea
The carina of trachea (also: "tracheal carina") is a ridge of cartilage at the base of the trachea separating the openings of the left and right main bronchi. Structure The carina is a cartilaginous ridge separating the left and right main bronchi that is formed by the inferior-ward and posterior-ward prolongation of the inferior-most tracheal cartilage. The carina occurs at the lower end of the trachea - usually at the level of the 4th to 5th thoracic vertebra. This is in line with the sternal angle, but the carina may raise or descend up to two vertebrae higher or lower with breathing. The carina lies to the left of the midline, and runs antero-posteriorly (front to back). Blood supply The bronchial arteries supply the carina and the rest of the lower trachea. Relations The carina is around the area posterior to where the aortic arch crosses to the left of the trachea. The azygos vein crosses right to the trachea above the carina. Physiology The mucous membrane ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclostomi
Cyclostomi, often referred to as Cyclostomata , from Ancient Greek κύκλος (kúklos), meaning "circle", and στόμα (stóma), meaning "mouth", is a superclass of vertebrates that comprises the living jawless fish classes: the lampreys and hagfishes. Both groups have jawless mouths with horny epidermal structures that function as teeth called ceratodontes, and branchial arches that are internally positioned instead of external as in the related jawed fishes. The superclass was named by Joan Crockford-Beattie. Possible external relationships This taxon is often included in the paraphyletic infraphylum Agnatha, which also includes several groups of extinct armored fishes called ostracoderms. Most fossil agnathans, such as galeaspids, thelodonts, and osteostracans, are more closely related to vertebrates with jaws (called gnathostomes) than to cyclostomes. Biologists historically disagreed on whether cyclostomes are a clade. The "vertebrate hypothesis" h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extracellular Matrix
In biology, the extracellular matrix (ECM), also called intercellular matrix (ICM), is a network consisting of extracellular macromolecules and minerals, such as collagen, enzymes, glycoproteins and hydroxyapatite that provide structural and biochemical support to surrounding cells. Because multicellularity evolved independently in different multicellular lineages, the composition of ECM varies between multicellular structures; however, cell adhesion, cell-to-cell communication and differentiation are common functions of the ECM. The animal extracellular matrix includes the interstitial matrix and the basement membrane. Interstitial matrix is present between various animal cells (i.e., in the intercellular spaces). Gels of polysaccharides and fibrous proteins fill the interstitial space and act as a compression buffer against the stress placed on the ECM. Basement membranes are sheet-like depositions of ECM on which various epithelial cells rest. Each type of connective tissue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
