Cellular Elements of Connective Tissue
Nikolay Petrovich Omelyanenko in Connective Tissue, 2014
As has already been stated, all cellular elements of connective tissue (see section 1.4.1) are mesenchyme derivatives. Despite the structural and functional diversity of these cells, they can be divided into two major groups: 1) the proper cells of connective tissue, i.e. the synthesizing components of the intercellular matrix and constantly renewing it under physiological conditions and restoring it under reparative conditions; and 2) cells associated with connective tissue, for which the latter is a medium of their vital activities but are not directly involved in the formation of the intercellular (extracellular) matrix. In turn, every allocated group can be subdivided into several subgroups according to different features.
Histology and Tissue Properties II: Connective Tissues
Qizhi Chen, George Thouas in Biomaterials, 2015
As briefly described in the previous chapter, connective tissue is a form of support tissue, containing varying amounts of fibrous proteins (collagen, elastin, and proteoglycans) and cells. The matrix structure of connective tissue provides varying degrees of mechanical support to all tissues, depending on the function of the tissue, particularly variable elasticity, fluid content, and porosity. Hence, biomaterials play a major role as a connective tissue substitute. Unlike epithelial, muscular, or nervous tissue, the major constituent of connective tissue is the extracellular matrix (ECM), with the cells that produce this matrix embedded within it. The ECM of connective tissues is what a biomaterial is aimed to replace.
Connective tissues
James Watkins in Fundamental Biomechanics of Sport and Exercise, 2014
All of the cells of the body are joined by connective tissue into progressively larger units, i.e. tissues, organs and systems. The whole body consists of all of the systems joined together. Connective tissue maintains the integrity of the tissues, organs and systems by providing them with adequate strength and elasticity. Connective tissue also facilitates intercellular exchange of gases and nutrients. Connective tissue is continuous throughout the body, but its structure gradually changes from one part of a tissue, organ or system to another, depending on the function of the connective tissue at each location. The purpose of this chapter is to describe the structure and functions of connective tissues.
Muscle and tendon connective tissue adaptation to unloading, exercise and NSAID
Published in Connective Tissue Research, 2014
The extracellular matrix network of skeletal muscle and tendon connective tissue is primarily composed of collagen and connects the muscle contractile protein to the bones in the human body. The mechanical properties of the connective tissue are important for the effectiveness of which the muscle force is transformed into movement. Periods of unloading and exercise affect the synthesis rate of connective tissue collagen protein, whereas only sparse information exits regarding collagen protein degradation. It is likely, though, that changes in both collagen protein synthesis and degradation are required for remodeling of the connective tissue internal structure that ultimately results in altered mechanical properties of the connective tissue. Both unloading and exercise lead to increased production of growth factors and inflammatory mediators that are involved in connective tissue remodeling. Despite the fact that non-steroidal anti-inflammatory drugs seem to inhibit the healing process of connective tissue and the stimulating effect of exercise on connective tissue protein synthesis, these drugs are often consumed in relation to connective tissue injury and soreness. However, the potential effect of non-steroidal anti-inflammatory drugs on connective tissue needs further investigation.
Connective Tissue Metabolism in Diabetic Peripheral Nerves
Published in Annals of Medicine, 1994
Diabetes mellitus is associated with multiple connective tissue changes, such as generalized thickening of basement membranes. These alterations are suspected of contributing to the development of diabetic long-term complications encountered in many organs, including kidney, eye and peripheral nerves. The latter tissue, however, has gained relatively little attention with respect to connective tissue changes associated with diabetes. The morphological alterations of connective tissue in the diabetic peripheral nerve include thickening of basement membranes, increased diameter of endoneurial collagen fibrils, and accumulation of microfibrillar material. Recent studies have further elucidated the changes in the extracellular matrix of diabetic nerves and the molecular mechanisms underlying these alterations. For instance, elevated glucose concentrations modulate the expression of several proteins of the extracellular matrix in cultured nerve-derived connective tissue cells. In this article, we review the recent progress in the field of connective tissue alterations in diabetes and particularly in the diabetic peripheral nerve.
Orbital pathology in thyroid-associated ophthalmopathy
Published in Orbit, 1996
Ruth van der Gaag, E. Donné Schmidt, Frans W. Zonneveld, Leo Koornneef
Thyroid-associated ophthalmopathy (TAO) is a disfiguring disease. The clinical symptoms are the consequence of inflammation in the orbital tissues in response to as yet unknown antigens, causing swelling of the extraocular muscles, edema and fibrosis, and subsequently eye movement impairment, exophthalmos and sometimes compression of the optic nerve. Analysis of orbits from 40 patients with Graves' ophthalmopathy showed an increased volume of both the extraocular muscles and the orbital adipose/connective tissue in 48%, increased muscle volume with normal adipose/connective tissue in 20% and normal muscles with increased adipose/connective tissue in 28%. The other orbits were normal (4%). Knowledge of the overall anatomy and the distribution of immunocompetent cells may help to shed light on the pathophysiology of TAO. In normal orbital tissues B-lymphocytes were scarce, but T-lymphocytes were numerous in normal extraocular muscles, orbital connective tissue septa and in the loose connective tissue surrounding the adipose tissue. The most predominant cell type in normal extraocular muscles and in the orbital connective tissue is the macrophage. In TAO, irrespective of the activity state, significant increases in numbers of macrophages were found in the minor connective tissue septa and in the levator palpebrae/Miiller's muscle complex. In the latter muscle complex the number of macrophages per mm2 is increased, whereas the number of HLA-DR+ cells is drastically reduced compared to controls. Overall these results show a shift in population from HLA-DRV macrophages, in control tissues, to HLA-DR7macrophages in orbital tissues obtained from patients with TAO.