CONNECTIVE AND ADIPOSE TISSUE
Connective tissue is a term applied to a tissue with mesodermal origin (embrionic). It is an animal tissue. Provides structural and metabolic support for other tissues, and mediate the exchange of nutrients and other substances between them. They are bathed by blood and lymphatic vessels. We can find different elements in this tissue: what are called supportcells, and what they form and sent to the extracellular medium, the extracellular matrix, which is the dominant component of some of connective tissue, and this determines the physical properties of each type.
EXTRACELULAR MATRIX= GEL-LIKE SUBSTANCE= GROUND SUBSTANCE + FIBERS
There are different types of support tisssues, as:
The come from mesenquimatic differencied cells. Thetissues that pertain to this tissue family have a low number of cells, disperse and varied. The space between cells is occupied by the matrix or intracellular matrix, that is formed by:
PROTEIN FIBERS: the most abundant are the collagen fibers, that give resistence , and elastine, which give elasticity.
GEL-LIKE SUBSTANCE: main component are polysacharids, where the proteic fibers are immersed.
Ithas support and structural, and store energetic functions.
* Loose- packing material
* Dense- physical support dermis, part of organs, ligaments and tendons
* Specialized connective tissue
KINDS OF CELLS
LOOSE CONCJUNCTIVE TISSUE
* Fybrocites: this are the most abundant, they are stellate,they synthesize extracellular matrix. They have moreactivity if they are fibroblasts.
* Macrofags: they are wandering cells, they come from the monocites, they phagocytose the damaged cells and patoghenic agents.
* Adipocytes: they are conformed by one lipidic vacuole that forms the fat tissue. They store a great quantity of fats.
* Myofibroblasts: contractile functiom and secretion of extracellular matrix.
EXTRACELLULAR MATRIX:FIBERS AND GROUND SUBSTANCE
As the name implies, these tissues perform connective and supportive functions: giving form to and anchoring the organs of the body. Unlike epithelium, connective tissues consist of one or more cell types embedded in a matrix. The matrix consists of widely dispersed fibers embedded in a ground substance, which may range in form from solid to liquid. A number of forms ofconnective tissues exist depending on the relative types, quantities, and arrangements of the three components: cells, fibers, and ground substance the types of connective tissue are summarized (with accompanying color photos) in Table 37-2 (pp. 806-806) of the text.
THE FIBERS OF SUPPORTING TISSUE/ CONNECTIVE TISSUE
Fribous components are collagen, reticulin (separate fiber type) andelastine.
COLLAGEN: is the main fiber type found in most supportive tissues and the most abundant protein in the body, provision of tensile strength. Is secreted to the extracellular matrix in form of tropocollagen (polypeptide chains, bond forming an helical structure), at the extracellular matrix they polymerise ti form collagen. 27 types of collagen.Collagen is common in loose connective tissue,dense connective tissue, reticular connective tissue, bone, and cartilage.
* Collagen Type I Fibers
* Three chains or strands, each of them with 1050 amino acids and approximately 300 nanometers long. Hydrogen bonds between amino acids in the different chains help hold them together and give the fiber a great deal of strength. Multiple collagen type I triple helices will join forming afibril like a rope that has high tensile strength. Extremely strong, and forms the primary component of tendons, connective tissue structures that link muscles and bones.
* Collagen Type II Fibers
* Protein in cartilage, nose, ears and many joints in your body. Collagen type II fibrils are smaller than collagen type I fibrils and assume random orientations in a gelatinous matrix of...
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