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Biology of the Hair and Skin
Published in Randy Schueller, Perry Romanowski, Conditioning Agents for Hair and Skin, 2020
The dermis is divided into two parts: the papillary dermis and the reticular dermis (13). The papillary dermis contains smaller collagen and elastic fibers than the reticular dermis, but encloses the extensive circulatory, lymphatic, and nervous system of the skin. It also contains fibronectins, which function as adhesive proteins to attach fibroblasts to collagen, and abundant glycosaminoglycans, also known as ground substance, which are anionic polysaccharides. The major glycosaminoglycans are hyaluronic acid, chondroitin sulfate, dermatan sulfate, and heparin sulfate. They function to maintain adequate water homeostasis within the skin and influence flow resistance to solutes. In essence they are the natural moisturizing substances of the skin, necessary to prevent cutaneous dehydration. They comprise only 0.2% of the dry weight of the skin, but are capable of binding water in volumes up to 1000 times their own.
Treatment Options for Chemical Sensitivity
Published in William J. Rea, Kalpana D. Patel, Reversibility of Chronic Disease and Hypersensitivity, Volume 5, 2017
William J. Rea, Kalpana D. Patel
Injection therapy appears to regulate many substances caught in the ECM, and the matrix's unique molecular anatomy and physiology, which allows provocation neutralization therapy to be effective. The ground substance matrix is made up of PG and GAG (glucosamines, hexoseamines, D-glucosamine, D-galactosamine, hyaluronic acids, heparin, chondroitin sulfates, dermatosulfates, and keratin sulfates). These substances are negatively charged linear carbohydrate chains that respond electrophysically and electrochemically. The PGs are sugar–protein biopolymers interspersed with water, which in itself experiences energy, have memory and bioelectric properties, and can thus be a vehicle to communicate with the rest of the body. Stabilization of this anatomical makeup of water interspersed between amino sugar molecules is through binding to a protein backbone that is bound to hyaluronic acid via binding proteins.299 These PGs also bind to the glycocalyx of the cell membrane, allowing for communication from the extracellular fluid to the cell membrane and through it. Therefore, intradermal and subcutaneous neutralization injections not only may stabilize disordered water but also will rapidly communicate with cells via this ground regulation system.
Chapter 1 Biomechanics
Published in B H Brown, R H Smallwood, D C Barber, P V Lawford, D R Hose, Medical Physics and Biomedical Engineering, 2017
Like bone, soft tissue is a composite material with many individual components. It is made up of cells intimately mixed with intracellular materials. The intracellular material consists of fibres of collagen, elastin, reticulin and a gel material called ground substance. The proportions of the materials depend on the type of tissue. Dense connective tissues generally contain relatively little of the ground substance and loose connective tissues contain rather more. The most important component of soft tissue with respect to the mechanical properties is usually the collagen fibre. The properties of the tissue are governed not only by the amount of collagen fibre in it, but also by the orientation of the fibres. In some tissues, particularly those that transmit a uniaxial tension, the fibres are parallel to each other and to the applied load. Tendons and ligaments are often arranged in this way, although the fibres might appear irregular and wavy in the relaxed condition. In other tissues the collagen fibres are curved, and often spiral, giving rise to complex material behaviour.
Development of biomimetic electrospun polymeric biomaterials for bone tissue engineering. A review
Published in Journal of Biomaterials Science, Polymer Edition, 2019
Sugandha Chahal, Anuj Kumar, Fathima Shahitha Jahir Hussian
Bone is a composite material which consists of both fluid and solid phases. Bone is hard because the organic extracellular collagenous matrix is impregnated with inorganic minerals of calcium phosphate, principally hydroxyapatite Ca10(PO4)6(OH)2. Calcium and phosphate account for roughly 65 to 70% of the bone's dry weight. The bone mineral has Ca/P ratio of 1.67, but it can vary from 1.37 to 1.87 due to the presence of additional minerals ions (refer to Table 1). Collagen fibers account approximately 25 to 30% of the bone matrix. Bone is mostly composed of type-I collagen and a very small percentage of type-IV. The type-I collagen molecules form the collagen fibrils and these collagen fibrils together form the tropocollagen in a parallel array [41]. Surrounding the mineralized collagen fibers is a ground substance consisting of protein polysaccharides, or glycosaminoglycans (GAGs), primarily in the form of complex macromolecules called proteoglycans. The GAGs assist to cement the various layers of mineralized collagen fibers together. The organic part of bone is responsible for its flexibility, while the inorganic material gives elasticity to bone [48,52,54].