Connective tissue
In the human body there are four types of primary body tissues: (1)
Epithelial, (2)
Connective, (3)
Muscle, and (4)
Nervous Tissue.
*
Blood functions in transport. Its extracellular matrix is
blood plasma, which transports dissolved
nutrients,
hormones, and
carbon dioxide in the form of
bicarbonate. The main cellular component is
red blood cells.
*
Cartilage makes up virtually the entire skeleton in
osteichthyes. In most other
vertebrates, it is found primarily in
joints, where it provides cushioning. The extracellular matrix of cartilage is composed primarily of
collagen.
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Connective tissue**
Dense connective tissue or
Fibrous connective tissue forms
ligaments and
tendons. Its densely packed collagen fibers have great tensile strength.
**
Loose connective tissue or
Areolar connective tissue holds organs and epithelia in place, and has a variety of
proteinaceous fibers, including collagen and
elastin. It is also important in inflammation.
**
Reticular connective tissue is a network of reticular fibers (fine collagen) that form a soft skeleton to support the
lymphoid organs (
lymph nodes,
bone marrow, and
spleen.)
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Adipose tissue contains
adipocytes, used for cushioning,
thermal insulation,
lubrication (primarily in the
pericardium) and
energy storage.
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Fiber types as follows:Collagenous fibers, elastic fibers, retucular fibers
Various connective tissue conditions have been identified; these can be both inherited and environmental.
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Marfan syndrome - a genetic disease causing abnormal
fibrillin.
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Scurvy - caused by a dietary deficiency in
vitamin C, leading to abnormal
collagen.
*
Ehlers-Danlos syndrome - a genetic disease causing progressive deterioration of collagens, with different EDS types affecting different sites in the body, such as joints, heart valves, organ walls, arterial walls, etc.
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Osteogenesis imperfecta (brittle bone disease) - caused by insufficient production of good quality collagen to produce healthy, strong bones.
* Spontaneous
pneumothorax - collapsed lung, believed to be related to subtle abnormalities in connective tissue.
*
Sarcoma - a neoplastic process originating in connective tissue.
See also:
zootomy
