Tenocyte

	Tenocyte Vertebrates Tendon cells, or tenocytes, are elongated fibroblast type cells. The cytoplasm is stretched between the collagen fibres of the tendon. They have a central cell nucleus with a prominent nucleolus. Tendon cells have a well-developed rough endoplasmic reticulum and they are responsible for synthesis and turnover of tendon fibres and ground substance. Invertebrates Tendon cells form a connecting epithelial layer between the muscle and shell in molluscs. In gastropods, for example, the retractor muscles connect to the shell via tendon cells. Muscle cells are attached to the collagenous myo-tendon space via hemidesmosomes. The myo-tendon space is then attached to the base of the tendon cells via basal hemidesmosomes, while apical hemidesmosomes, which sit atop microvilli, attach the tendon cells to a thin layer of collagen. This is in turn attached to the shell via organic fibres which insert into the shell. Molluscan tendon cells appear columnar and contain a l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Bing] [Yahoo] [DuckDuckGo] [Baidu]
picture info	Tendon A tendon or sinew is a tough, high-tensile-strength band of dense fibrous connective tissue that connects muscle to bone. It is able to transmit the mechanical forces of muscle contraction to the skeletal system without sacrificing its ability to withstand significant amounts of tension. Tendons are similar to ligaments; both are made of collagen. Ligaments connect one bone to another, while tendons connect muscle to bone. Structure Histologically, tendons consist of dense regular connective tissue. The main cellular component of tendons are specialized fibroblasts called tendon cells (tenocytes). Tenocytes synthesize the extracellular matrix of tendons, abundant in densely packed collagen fibers. The collagen fibers are parallel to each other and organized into tendon fascicles. Individual fascicles are bound by the endotendineum, which is a delicate loose connective tissue containing thin collagen fibrils and elastic fibres. Groups of fascicles are bounded by the epite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Bing] [Yahoo] [DuckDuckGo] [Baidu]
	Hemidesmosomes Hemidesmosomes are very small stud-like structures found in keratinocytes of the epidermis of skin that attach to the extracellular matrix. They are similar in form to desmosomes when visualized by electron microscopy, however, desmosomes attach to adjacent cells. Hemidesmosomes are also comparable to focal adhesions, as they both attach cells to the extracellular matrix. Instead of desmogleins and desmocollins in the extracellular space, hemidesmosomes utilize integrins. Hemidesmosomes are found in epithelial cells connecting the basal epithelial cells to the lamina lucida, which is part of the basal lamina. Hemidesmosomes are also involved in signaling pathways, such as keratinocyte migration or carcinoma cell intrusion. Structure Hemidesmosomes can be categorized into two types based on their protein constituents. Type 1 hemidesmosomes are found in stratified and pseudo-stratified epithelium. Type 1 hemidesmosomes have five main elements: integrin α6 β4, plectin in it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Bing] [Yahoo] [DuckDuckGo] [Baidu]
picture info	Human Cells There are many different types of cells in the human body. Cells derived primarily from endoderm Exocrine secretory epithelial cells * Brunner's gland cell in duodenum ( enzymes and alkaline mucus) Insulated goblet cell of respiratory and digestive tracts (mucus secretion) Stomach Foveolar cell (mucus secretion) Chief cell (pepsinogen secretion) ** Parietal cell (hydrochloric acid secretion) * Pancreatic acinar cell (bicarbonate and digestive enzyme secretion) * Paneth cell of small intestine (lysozyme secretion) Type II pneumocyte of lung ( surfactant secretion) Club cell of lung Barrier cells Type I pneumocyte (lung) Gall bladder epithelial cell * Centroacinar cell (pancreas) * Intercalated duct cell (pancreas) Intestinal brush border cell (with microvilli) Hormone-secreting cells Enteroendocrine cell K cell (secretes gastric inhibitory peptide) L cell (secretes glucagon-like peptide-1, peptide YY3-36, oxyntomodulin, and glucagon-like peptide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Bing] [Yahoo] [DuckDuckGo] [Baidu]