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Comparative Anatomy, Physiology, and Biochemistry of Mammalian Skin
Published in David W. Hobson, Dermal and Ocular Toxicology, 2020
The dermis or corium lies beneath the basal lamina and extends to the hypodermis. The dermis is of mesodermal origin and consists largely of dense, irregular connective tissue (Figure 13). In this matrix, fibrous proteins such as collagen, elastin, and reticulin are embedded in an amorphous ground substance. The predominant cell types of the dermis are fibroblasts, mast cells, and macrophages. Plasma cells, fat cells, and extravasated leukocytes are often found. The dermis is traversed by blood vessels, lymphatics, and nerves. Glandular structures such as sebaceous and sweat glands are also found in this connective tissue matrix, along with hair follicles.
Introduction and Review of Biological Background
Published in Luke R. Bucci, Nutrition Applied to Injury Rehabilitation and Sports Medicine, 2020
Just under the fibrous joint capsule, the dense irregular connective tissue that surrounds most joint structures, the synovium, is found. The synovium is divided into two layers — the subintima and intima. There is no basement membrane in synovium. The subintima is highly vascular, loose connective tissue and contains nerves and lymphatics. The intima is one to four cells thick and faces the inside of the joint cavity. Two major cell types are present in the subintima. Type A cells are macrophage-like, and Type B cells are fibroblast-like. However, these cells have overlapping functions, which has led some investigators to identify Type C cells (intermediate synovial cells). Both synthetic and phagocytic properties are possessed by synoviocytes. In vitro, synovial cells secrete hyaluronan, proteoglycans, collagens (Types I, III), collagenases, neutral metalloproteinases, activators of collagenases and proteases, fibronectin, laminin, and many other unidentified matrix constituents. Importantly, synoviocytes also can be induced to secrete interleukin-1 (IL-1), prostaglandin E2, and possibly other cytokines and lymphokines.33,63–65 Thus, synoviocytes are extremely important in regulating the degradation of cartilage, and, thus, joint function.
De Fabrica Humani Corporis—Fascia as the Fabric of the Body
Published in David Lesondak, Angeli Maun Akey, Fascia, Function, and Medical Applications, 2020
The growing body of evidence supports the move away from thinking about fasciae as discrete anatomical elements and toward the definition of fascia as a system (a “whole”).5,7 Schleip puts it as follows: “Fascia is the dense irregular connective tissue that surrounds and connects every muscle, even the last myofibril, and every single organ of the body, forming continuity throughout the body”.8
Anatomic variations of the human falx cerebelli and its association with occipital venous sinuses
Published in British Journal of Neurosurgery, 2021
Safiye Çavdar, Bilgehan Solmaz, Özgül Taniş, Orhan Ulas Guler, Hakkı Dalçık, Evren Aydoğmuş, Leyla Altunkaya, Erdoğan Kara, Hızır Aslıyüksek
Falx cerebelli, is composed of fibroelastic, dense irregular connective tissue. The connective tissue consisted of cells predominantly of fibroblast which produced the ground substance and collagen fibers. Additionally, the connective tissue contained sensory nerve endings and blood vessels. The arterioles were composed of 1–2 layers of smooth muscle cells in the tunica media and the venules were composed of a single layer of endothelium with many erythrocytes in their lumens (Figure 10a). Furthermore, a large number of lymphatic vessels appeared to be undulated with a single layer of endothelium and a subendothelial layer (Figure 10b). Extravagated lymphocytes surrounding the lymphatic vessels were observed (Figure 10b). Near the vessels, a peripheral nerve characteristically formed a round bundle of nerve processes surrounded by connective tissue sheath perineurium was detected (Figure 10a).
Effect of ultraviolet radiation on the Nrf2 signaling pathway in skin cells
Published in International Journal of Radiation Biology, 2021
Alena Ryšavá, Jitka Vostálová, Alena Rajnochová Svobodová
The dermis consists primarily of dense, irregular connective tissue within a matrix of collagen and elastin fibers, which make it compressible and elastic. Fibroblasts, spindle-shaped cells with a well-developed rough endoplasmic reticulum, are the predominant cells in the dermis. Fibroblasts synthesize all dermal fibers and components of the extracellular matrix (Figure 1) (Mescher 2016). Other cell types in the dermis include mast cells, macrophages, adipocytes and plasma cells. It is interwoven with nerve fibers and blood and lymphatic vessels that also supply nutrients to the epidermis (Svobodová and Vostálová 2010).
Role of Smoking-Mediated molecular events in the genesis of oral cancers
Published in Toxicology Mechanisms and Methods, 2019
The teeth and gums positioning partition oral cavity into two major sections: oral vestibule and oral cavity proper (Gray 1918). Orifice of mouth opens into oral vestibule followed by oral cavity proper. The oral vestibule is a narrow slit-like space enclosed by buccal mucosa of cheeks & lips, teeth stacks and the gingival wall (gums). The oral cavity proper is the space constituting of maxillary (upper) and mandibular (lower) dental alveolar arches, hard palate, soft palate, 2/3rd anterior tongue, and floor of the mouth. When upper and lower teeth stacks are in contact, the oral vestibule and oral cavity proper communicate through gaps between last molars and ramus of the mandible (Gray 1918; NCI 2018). Oral cavity and oropharynx are continuous through oropharyngeal isthmus (Melo et al. 2018). Tonsillar fossa-pillars forms the base and start for oral cavity and oropharynx respectively (Batsakis 2003; Chen and Chao 2012). The tonsillar fossa is a triangular region bordered by an anterior-posterior tonsillar pillar (palatoglossal-palatopharyngeal arches) and occupied by the palatine tonsil (Gray 1918). The intra-oral surfaces are covered with less keratinized, more pinkish non-masticatory and thin mucosa; while the exceptional subsites of the hard palate, dorsal surface of the tongue, and gingiva are covered with highly keratinized, pale masticatory and firm-stippled mucosa covers (Dadgostar 2015). The oral mucosal tissue comprises of epithelial layers (stratified squamous cells) as the outermost part (facing the oral cavity) followed by basement membrane (basal lamina), and lower connective tissue lamina propria (loose irregular connective tissue); beneath oral mucosa lies submucosal layer (dense irregular connective tissue) (Squier and Kremer 2001; Hamdoon 2013; Cruchley and Bergmeier 2018).