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In addition to their role as UV radical scavengers, melanocytes are also part of the immune system, and are considered to be immune cells. [20] Although the full role of melanocytes in immune response is not fully understood, melanocytes share many characteristics with dendritic cells : branched morphology; phagocytic capabilities; presentation ...
In some melanocytes, the melanosomes remain static within the cell. In others the cell can extend its surface lengthwise as temporary projections known as pseudopodia , which carry melanosomes away from the center of the cell, thereby increasing the cell's effectiveness in absorbing light.
Sampling of human stratum corneum using a tape-stripping method [1]. The stratum corneum (Latin for 'horned layer') is the outermost layer of the epidermis.Consisting of dead tissue, it protects underlying tissue from infection, dehydration, chemicals and mechanical stress.
The neural crest is a ridge-like structure that is formed transiently between the epidermal ectoderm and neural plate during vertebrate development. Neural crest cells originate from this structure through the epithelial-mesenchymal transition, and in turn give rise to a diverse cell lineage—including melanocytes, craniofacial cartilage and bone, smooth muscle, dentin, peripheral and enteric ...
Although, in general, human beings possess a similar concentration of melanocytes in their skin, the melanocytes in some individuals and ethnic groups produce variable amounts of melanin. The ratio of eumelanin (74%) and pheomelanin (26%) in the epidermis is constant regardless of the degree of pigmentation. [ 27 ]
Each melanocyte in the epidermis has several dendrites that stretch out to connect it with many keratinocytes. The melanin is then stored within keratinocytes and melanocytes in the perinuclear area as supranuclear "caps", where it protects the DNA from UVR-induced damage .
One study compared the two shapes and recorded data that showed spherical particles located deep in the epidermis and dermis whereas ellipsoidal particles were mainly found in the stratum corneum and epidermal layers. [48] Nanorods are used in experiments because of their unique fluorescent properties but have shown mediocre penetration.
A major application of Walsh diagrams is to explain the regularity in structure observed for related molecules having identical numbers of valence electrons (e.g. why H 2 O and H 2 S look similar), and to account for how molecules alter their geometries as their number of electrons or spin state changes.