As the name implies, connective tissue serves a connecting function: It supports and binds other tissues in the body. Unlike epithelial tissue, which has cells that are closely packed together, connective tissue typically has cells scattered throughout an extracellular matrix of fibrous proteins and glycoproteins attached to a basement membrane. The primary elements of connective tissue include a ground substance, fibers, and cells. Show
There are three main groups of connective tissues:
The ground substance acts as a fluid matrix that suspends the cells and fibers within the particular connective tissue type. Connective tissue fibers and matrix are synthesized by specialized cells called fibroblasts. There are three main groups of connective tissues: loose connective tissue, dense connective tissue, and specialized connective tissue. In vertebrates, the most common type of connective tissue is loose connective tissue. It holds organs in place and attaches epithelial tissue to other underlying tissues. Loose connective tissue is named so because of the "weave" and type of its constituent fibers. These fibers form an irregular network with spaces between the fibers. The spaces are filled with ground substance. The three main types of loose connective fibers include collagenous, elastic, and reticular fibers.
Loose connective tissues provide support, flexibility, and strength required to support internal organs and structures such as blood vessels, lymph vessels, and nerves. Dense Connective TissueThis image of the dermis of the skin shows dense fibrous connective tissue. Irregular collagenous fibers (pink) and fibroblast nuclei (purple) can be seen. Ed Reschke/Photolibrary/Getty ImagesAnother type of connective tissue is dense or fibrous connective tissue, which can be found in tendons and ligaments. These structures help attach muscles to bones and link bones together at joints. Dense connective tissue is composed of large amounts of closely packed collagenous fibers. In comparison to loose connective tissue, dense tissue has a higher proportion of collagenous fibers to ground substance. It is thicker and stronger than loose connective tissue and forms a protective capsule layer around organs such as the liver and kidneys. Dense connective tissue can be categorized into dense regular, dense irregular, and elastic connective tissues.
Specialized Connective TissuesThis image shows a sample of fat tissue with fat cells (adipocytes, blue) surrounded by fine strands of supportive connective tissue. Adipose tissue forms an insulating layer under the skin, storing energy in the form of fat. Steve Gschmeissner/Science Photo Library/Getty ImagesSpecialized connective tissues include a number of different tissues with specialized cells and unique ground substances. Some of these tissues are solid and strong, while others are fluid and flexible. Examples include adipose, cartilage, bone, blood, and lymph. Adipose TissueAdipose tissue is a form of loose connective tissue that stores fat. Adipose lines organs and body cavities to protect organs and insulate the body against heat loss. Adipose tissue also produces endocrine hormones that influence activities such as blood clotting, insulin sensitivity, and fat storage. The primary cells of adipose are adipocytes. These cells store fat in the form of triglycerides. Adipocytes appear round and swollen when fat is being stored and shrink as fat is used. Most adipose tissue is described as white adipose which functions in the storage of energy. Both brown and beige adipose burn fat and produce heat. CartilageCartilage is a form of fibrous connective tissue that is composed of closely packed collagenous fibers in a rubbery gelatinous substance called chondrin. The skeletons of sharks and human embryos are composed of cartilage. Cartilage also provides flexible support for certain structures in adult humans including the nose, trachea, and ears. There are three different types of cartilage, each with different characteristics.
Bone TissueThis micrograph shows cancellous (spongy) bone from a vertebra. Cancellous bone is characterized by a honeycomb arrangement, comprising a network of trabeculae (rod-shaped tissue). These structures provide support and strength to the bone. Susumu Nishinaga/Science Photo Library/Getty ImagesBone is a type of mineralized connective tissue that contains collagen and calcium phosphate, a mineral crystal. Calcium phosphate gives bone its firmness. There are two types of bone tissue: spongy and compact.
Blood and LymphInterestingly enough, blood is considered to be a type of connective tissue. Like other connective tissue types, blood is derived from mesoderm, the middle germ layer of developing embryos. Blood also serves to connect other organ systems together by supplying them with nutrients and transporting signal molecules between cells. Plasma is the extracellular matrix of blood with red blood cells, white blood cells, and platelets suspended in the plasma. Lymph is another type of fluid connective tissue. This clear fluid originates from blood plasma that exits blood vessels at capillary beds. A component of the lymphatic system, lymph contains immune system cells that protect the body against pathogens. Lymph is delivered back to blood circulation via lymphatic vessels. Animal Tissue TypesIn addition to connective tissue, other tissue types of the body include:
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What type of connective tissue contains osteocytes and stores calcium in the matrix?Bone is a strong, flexible and semi-rigid supporting tissue. It can withstand compression forces, and yet it can bend. Like cartilage, and other types of connective tissue, bone is made up of Cells and Extracellular matrix: Cells - which in bone are called osteoblasts and osteocytes, (osteo - bone).
Which connective tissue has a hard calcified matrix?Bone tissue is a supportive type of connective tissue. It acts to shield the internal organs and to provide structure and support. Bone tissue includes compact bone and spongy bone. In bone, the matrix is rigid and described as calcified because of the deposited calcium salts.
What is the type of connective tissue that is a solid matrix made of calcium?Bones are organs that consist primarily of bone tissue, also called osseous tissue. Bone tissue is a type of connective tissue consisting mainly of a collagen matrix that is mineralized with calcium and phosphorus crystals.
What tissue has a calcified matrix?Bone is highly vascularised, and its calcified matrix makes it very strong. This topic covers the structure and function of bone and cartilage, the type of cells found in these tissues, and how bone and cartilage are formed.
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