Search results
Results From The WOW.Com Content Network
Histologic image of the epidermis with its layers named in white text.. The Malpighian layer (stratum mucosum or stratum malpighii) of the epidermis is generally defined as both the stratum basale (basal layer) and the thicker stratum spinosum (spinous layer/prickle cell layer) immediately above it as a single unit, [1] [2] although it is occasionally defined as the stratum basale specifically ...
The neural tube cells give rise to the central nervous system, neural crest cells give rise to the peripheral and enteric nervous system, melanocytes, and facial cartilage, and the epidermal region will give rise to the epidermis, hair, nails, sebaceous glands, olfactory and oral epithelium, and eyes.
The epidermis primarily consists of keratinocytes [4] (proliferating basal and differentiated suprabasal), which comprise 90% of its cells, but also contains melanocytes, Langerhans cells, Merkel cells, [6]: 2–3 and inflammatory cells. Epidermal thickenings called Rete ridges (or rete pegs) extend downward between dermal papillae. [7]
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 ...
After formation of the tube, the brain forms into three sections; the hindbrain, the midbrain, and the forebrain. The types of neuroectoderm include: Neural crest. pigment cells in the skin; ganglia of the autonomic nervous system; dorsal root ganglia. facial cartilage; aorticopulmonary septum of the developing heart and lungs; ciliary body of ...
During the third week of embryonic growth, the brain begins to develop in the early fetus in a process called morphogenesis. [2] Neuroepithelial cells of the ectoderm begin multiplying rapidly and fold in forming the neural plate, which invaginates during the fourth week of embryonic growth and forms the neural tube. [2]
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 ...
Stages of development of the brain vesicles. Four neural tube subdivisions each eventually develop into distinct regions of the central nervous system by the division of neuroepithelial cells: the forebrain (prosencephalon), the midbrain (mesencephalon), the hindbrain (rhombencephalon) and the spinal cord.