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Lens Placode
The Lens placode is a thickened portion of ectoderm which serves as the precursor to the lens A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements .... SOX2 and Pou2f1 are involved in its development. See also * Placode References External links * * https://web.archive.org/web/20071213145329/http://cwx.prenhall.com/bookbind/pubbooks/martini10/chapter18/custom3/deluxe-content.html * https://web.archive.org/web/20070912010420/http://isc.temple.edu/neuroanatomy/lab/embryo_new/eye/2/ Embryology of nervous system Eye {{developmental-biology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Ectoderm
The surface ectoderm (or external ectoderm) forms the following structures: *Skin (only epidermis; dermis is derived from mesoderm) (along with glands, hair, and nails) *Epithelium of the mouth and nasal cavity and glands of the mouth and nasal cavity *Tooth enamel (as a side note, dentin and dental pulp are formed from ectomesenchyme which is derived from ectoderm (specifically neural crest cells and travels with mesenchmyal cells) *Epithelium of anterior pituitary *Lens, cornea, lacrimal gland, tarsal glands and the conjunctiva of the eye *Apical ectodermal ridge inducing development of the limb buds of the embryo. *Sensory receptors in epidermis See also *List of human cell types derived from the germ layers This is a list of cells in humans derived from the three embryonic germ layers – ectoderm, mesoderm, and endoderm. Cells derived from ectoderm Surface ectoderm Skin * Trichocyte * Keratinocyte Anterior pituitary * Gonadotrope * Corticotro ... References Exte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lens (anatomy)
The lens, or crystalline lens, is a transparent biconvex structure in the eye that, along with the cornea, helps to refract light to be focused on the retina. By changing shape, it functions to change the focal length of the eye so that it can focus on objects at various distances, thus allowing a sharp real image of the object of interest to be formed on the retina. This adjustment of the lens is known as '' accommodation'' (see also below). Accommodation is similar to the focusing of a photographic camera via movement of its lenses. The lens is flatter on its anterior side than on its posterior side. In humans, the refractive power of the lens in its natural environment is approximately 18 dioptres, roughly one-third of the eye's total power. Structure The lens is part of the anterior segment of the human eye. In front of the lens is the iris, which regulates the amount of light entering into the eye. The lens is suspended in place by the suspensory ligament of the lens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pou2f1
POU domain, class 2, transcription factor 1 is a protein that in humans is encoded by the ''POU2F1'' gene. Interactions POU2F1 has been shown to interact with: * EPRS, * Glucocorticoid receptor, * Glyceraldehyde 3-phosphate dehydrogenase, * Host cell factor C1, * Ku80, * MNAT1 * NPAT, * Nuclear receptor co-repressor 2, * POU2AF1, * RELA, * Retinoid X receptor alpha, * SNAPC4, * Sp1 transcription factor, and * TATA binding protein. See also * Octamer transcription factor Octamer transcription factors are a protein family, family of transcription factors which binds to the "ATTTGCAT" Nucleic acid sequence, DNA sequence. Their DNA-binding domain is a POU domain. There are eight Octamer proteins in humans (Oct1–11) ... References Further reading * * * * * * * * * * * * * * * * * * External links * {{Transcription factors, g3 POU-domain proteins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Placode
A neurogenic placode is an area of thickening of the epithelium in the embryonic head ectoderm layer that gives rise to neurons and other structures of the sensory nervous system. Placodes are embryonic structures that give rise to structures such as hair follicles, feathers and teeth. The term "neurogenic placode" generally refers to cranial placodes that have neurogenic potential - i.e. those that give rise to neurons associated with the special senses and cranial ganglia. Cranial placodes include a diverse range of structures found across chordates, but the neurogenic placodes found in vertebrates arose later in evolution. In humans The cranial placodes that have neurogenic potential (i.e. give rise to neurons) can be divided into two groups, the dorsolateral placodes and the epibranchial placodes. * dorsolateral placodes includes: ** The trigeminal placode, which consists of ophthalmic and maxillomandibular parts, and gives rise to the cells of the trigeminal ganglion ** Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embryology Of Nervous System
Embryology (from Greek ἔμβρυον, ''embryon'', "the unborn, embryo"; and -λογία, ''-logia'') is the branch of animal biology that studies the prenatal development of gametes (sex cells), fertilization, and development of embryos and fetuses. Additionally, embryology encompasses the study of congenital disorders that occur before birth, known as teratology. Early embryology was proposed by Marcello Malpighi, and known as preformationism, the theory that organisms develop from pre-existing miniature versions of themselves. Aristotle proposed the theory that is now accepted, epigenesis. Epigenesis is the idea that organisms develop from seed or egg in a sequence of steps. Modern embryology, developed from the work of Karl Ernst von Baer, though accurate observations had been made in Italy by anatomists such as Aldrovandi and Leonardo da Vinci in the Renaissance. Comparative embryology Preformationism and epigenesis As recently as the 18th century, the prevailing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
