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The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and hypodermis. [1] The epidermal layer provides a barrier to infection from environmental pathogens [2] and regulates the amount of water released from the body into the atmosphere through transepidermal water loss.
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 ...
Tanycytes are highly specialized ependymal cells found in the third ventricle of the brain, and on the floor of the fourth ventricle. Each tanycyte has a long basal process that extends deep into the hypothalamus. It is possible that their function is to transfer chemical signals from the cerebrospinal fluid to the central nervous system.
Embryonic vertebrate subdivisions of the developing human brain hindbrain or rhombencephalon is a developmental categorization of portions of the central nervous system in vertebrates. It includes the medulla , pons , and cerebellum .
The apical ectodermal ridge (AER) is a structure that forms from the ectodermal cells at the distal end of each limb bud and acts as a major signaling center to ensure proper development of a limb. After the limb bud induces AER formation, the AER and limb mesenchyme —including the zone of polarizing activity (ZPA)—continue to communicate ...
Located between the stratum granulosum and stratum corneum layers, it is composed of three to five layers of dead, flattened keratinocytes. [ 3 ] [ 4 ] The keratinocytes of the stratum lucidum do not feature distinct boundaries and are filled with eleidin , an intermediate form of keratin .
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. [50] Nanorods are used in experiments because of their unique fluorescent properties but have shown mediocre penetration.
The trunk of the body contains, from superior to inferior, the thoracic region encompassing the chest [1] the mammary region encompassing each breast; the sternal region encompassing the sternum; the abdominal region encompassing the stomach area; the umbilical region is located around the navel; the coxal region encompassing the lateral (side ...