Network blood vessel

Blood platelets are key players in the blood-clotting mechanism. These tiny fragments of cytoplasm are shed into the circulation from the surface of megakaryocytes located in the bone marrow. When the lining of a blood vessel is injured, activated platelets release clotting factors, adhere to each other and to damaged surfaces, and send out numerous filopodia. The shape changes that occur in activated platelets are the result of actin polymerization. Before activation, there are no microfilaments because profilin binds to G-actin and prevents its polymerization. After activation, profilin dissociates from G-actin, and bundles and networks of F-actin filaments rapidly appear within the platelet. 

Approximately 15 per cent of osteoblasts become entrapped in their own matrix to become osteocytes. Osteocytes have a vast three-dimensional network of cell processes (canaliculi), providing nourishment and cell-cell interactions. Because they are located throughout bone tissue and have an extensive canalicular network, osteocytes are assumed to be a vital component of sensing mechanical signals. Nutrients are essential for the vitality of bone tissue and are obtained from the blood supply, limiting most osteocytes to lie within 150 p.m of a blood vessel, resulting in a high cellular density 25000 osteocytes within a square millimetre of bone... 

Figure 2. Idealized solid tumor, after Jain.45 It has been partly cut away to reveal the complex network of blood vessels.

Blood vessel A tube in the body through which blood circulates. Blood vessels include a network of arteries, arterioles, capillaries, venules, and veins. [NIH]... 

Type I, II, and III collagens are fibrillar, and are found in tendon, skin, bone, cornea, carti lage, vitreous body, and blood vessels. Types IX and XII are fibril-associated, and are found in cartilage, tendon, and ligaments. Type IV and VII form networks in basement membrane and beneath stratified squamous epithelia. 

The lungs are covered extensively by a vast network of blood vessels, and almost all the blood in circulation flows through lungs. Deoxygenated blood is supplied to the lungs by the pulmonary artery. The pulmonary veins are similar to the arteries in branching, and their tissue structure is similar to that of systemic circulation. The total blood volume of the lungs is about 450 mL, which is about 10 percent of total-body blood volume.118... 

The TEMs revealed a change of material structure in the contact region with the newly built blood vessel. Beside cellulose we discovered still different structures in region 1 (Fig. 24a). Branches of fibroblasts, cellular compounds of the newly built vessel, have penetrated the cellulosic network and in this way anchored themselves in the artificial vessel prosthesis. Sections of the fibroblast branches and the contact region are clearly visible (Fig. 24b). 

The system that circulates blood is the cardiovascular system, shown in schematic form in Figure 9.1. It consists of two major components the muscular part of the heart, called the myocardium, and the network of blood vessels composed of arteries, veins, and capillaries. Blood circulation is the body s transportation system that supplies tissues with the oxygen, nutrients and their metabolites, and hormones that they need for their function. Blood carries carbon dioxide, encapsulated dead cell matter, and other wastes away from tissues. Circulating blood is crucial to maintaining body homeostasis, with temperature, pH, and other crucial parameters kept within the narrow ranges required for good health. A number of toxicants have adverse effects on the cardiovascular system. 

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