Hard tissue are lightweight yet strong and hard, and serve multiple functions. Mineralized osseous tissue or bone tissue, is of two types – cortical and cancellous and gives it rigidity and a coral-like three-dimensional internal structure. Other types of tissue found in bones include marrow, endosteum, periosteum, nerves, blood vessels and cartilage. Bone is an active tissue composed of different cells. Osteoblasts are involved in the creation and mineralisation of bone; osteocytes and osteoclasts are involved in the reabsorption of bone tissue. The mineralised matrix of bone tissue has an organic component mainly of collagen and an inorganic component of bone mineral
Fatty streak Fatty streak A fatty streak is the first grossly visible (visible to the naked eye) lesion in the development of atherosclerosis. It appears as an irregular yellow-white discoloration on the luminal surface of an artery. It consists of aggregates of foam cells, which are lipoprotein-loaded macrophages, located in the intima, the innermost layer of the artery, beneath the endothelial cells that layer the lumina through which blood flows. Fatty streaks may also include T cells, aggregated platelets, and smooth muscle cells. It is the precursor lesion of atheromas that may become atheromatous plaques. Almost all children older than 10 in