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Solitary Chemosensory Cells
{{More footnotes needed, date=October 2018 Solitary chemosensory cells (SCCs) (also called solitary chemoreceptor cells) are isolated elements located in epithelia of the apparatuses of endodermic origin (such as respiratory and digestive apparatuses). In the aquatic vertebrates, SCCs are also present in the skin. In oral cavity, SCCs precedes the development of taste buds. For long time, SCCs were considered to be typical of aquatic vertebrates. Recently, these elements were also demonstrated in mammals. The SCCs share common morphological and biochemical characteristics with the taste cells located in taste buds of the oro-pharyngeal cavity. In particular, they may express molecules of the chemoreceptorial cascade (such as trans-membrane taste receptors, the G-protein gustducin, PLCbeta2, IP3R3, TRPM5). Morphologically, the elements of SCCs are polymorphic. Some of them have an apical tuft of rigid microvilli Microvilli (singular: microvillus) are microscopic cellular membran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epithelia
Epithelium or epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is a thin, continuous, protective layer of compactly packed cells with a little intercellular matrix. Epithelial tissues line the outer surfaces of organs and blood vessels throughout the body, as well as the inner surfaces of cavities in many internal organs. An example is the epidermis, the outermost layer of the skin. There are three principal shapes of epithelial cell: squamous (scaly), columnar, and cuboidal. These can be arranged in a singular layer of cells as simple epithelium, either squamous, columnar, or cuboidal, or in layers of two or more cells deep as stratified (layered), or ''compound'', either squamous, columnar or cuboidal. In some tissues, a layer of columnar cells may appear to be stratified due to the placement of the nuclei. This sort of tissue is called pseudostratified. All glands are made up of epithelia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endoderm
Endoderm is the innermost of the three primary germ layers in the very early embryo. The other two layers are the ectoderm (outside layer) and mesoderm (middle layer). Cells migrating inward along the archenteron form the inner layer of the gastrula, which develops into the endoderm. The endoderm consists at first of flattened cells, which subsequently become columnar. It forms the epithelial lining of multiple systems. In plant biology, endoderm corresponds to the innermost part of the cortex ( bark) in young shoots and young roots often consisting of a single cell layer. As the plant becomes older, more endoderm will lignify. Production The following chart shows the tissues produced by the endoderm. The embryonic endoderm develops into the interior linings of two tubes in the body, the digestive and respiratory tube. Liver and pancreas cells are believed to derive from a common precursor. In humans, the endoderm can differentiate into distinguishable organs after 5 week ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taste Buds
Taste buds contain the taste receptor cells, which are also known as gustatory cells. The taste receptors are located around the small structures known as papillae found on the upper surface of the tongue, soft palate, upper esophagus, the cheek, and epiglottis. These structures are involved in detecting the five elements of taste perception: saltiness, sourness, bitterness, sweetness and umami. A popular myth assigns these different tastes to different regions of the tongue; in fact, these tastes can be detected by any area of the tongue. Via small openings in the tongue epithelium, called taste pores, parts of the food dissolved in saliva come into contact with the taste receptors. These are located on top of the taste receptor cells that constitute the taste buds. The taste receptor cells send information detected by clusters of various receptors and ion channels to the gustatory areas of the brain via the seventh, ninth and tenth cranial nerves. On average, the human to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gustducin
Gustducin is a G protein associated with taste and the gustatory system, found in some taste receptor cells. Research on the discovery and isolation of gustducin is recent. It is known to play a large role in the transduction of bitter, sweet and umami stimuli. Its pathways (especially for detecting bitter stimuli) are many and diverse. An intriguing feature of gustducin is its similarity to transducin. These two G proteins have been shown to be structurally and functionally similar, leading researchers to believe that the sense of taste evolved in a similar fashion to the sense of sight. Gustducin is a heterotrimeric protein composed of the products of the GNAT3 (α-subunit), GNB1 (β-subunit) and GNG13 (γ-subunit). Discovery Gustducin was discovered in 1992 when degenerate oligonucleotide primers were synthesized and mixed with a taste tissue cDNA library. The DNA products were amplified by the polymerase chain reaction method, and eight positive clones were shown to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TRPM5
Transient receptor potential cation channel subfamily M member 5 (TRPM5), also known as long transient receptor potential channel 5 is a protein that in humans is encoded by the ''TRPM5'' gene. Function TRPM5 is a calcium-activated non-selective cation channel that induces depolarization upon increases in intracellular calcium, it is a signal mediator in chemosensory cells. Channel activity is initiated by a rise in the intracellular calcium, and the channel permeates monovalent cations as K+ and Na+. TRPM5 is a key component of taste transduction in the gustatory system of bitter, sweet and umami tastes being activated by high levels of intracellular calcium. It has also been targeted as a possible contributor to fat taste signaling. The calcium dependent opening of TRPM5 produces a depolarizing generator potential which leads to an action potential. TRPM5 is expressed in pancreatic β-cells where it is involved in the signaling mechanism for insulin secretion. The potentiat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microvilli
Microvilli (singular: microvillus) are microscopic cellular membrane protrusions that increase the surface area for diffusion and minimize any increase in volume, and are involved in a wide variety of functions, including absorption, secretion, cellular adhesion, and mechanotransduction. Structure Microvilli are covered in plasma membrane, which encloses cytoplasm and microfilaments. Though these are cellular extensions, there are little or no cellular organelles present in the microvilli. Each microvillus has a dense bundle of cross-linked actin filaments, which serves as its structural core. 20 to 30 tightly bundled actin filaments are cross-linked by bundling proteins fimbrin (or plastin-1), villin and espin to form the core of the microvilli. In the enterocyte microvillus, the structural core is attached to the plasma membrane along its length by lateral arms made of myosin 1a and Ca2+ binding protein calmodulin. Myosin 1a functions through a binding site for filamentous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffuse Chemosensory System
The diffuse chemosensory system (DCS) is an anatomical structure composed of solitary chemosensory cells and chemosensory clusters. The concept of DCS has been advanced in 2005, after the discovery that cells similar to gustatory elements are present in several organs of the respiratory and digestive apparatuses. The elements forming the DCS share common morphological and biochemical characteristics with the taste cells located in taste buds of the oropharyngeal cavity. In particular, they may express molecules of the chemoreceptorial cascade (e.g. trans-membrane taste receptors, the G-protein gustducin, PLCbeta2, IP3R3, TRPM5). Morphologically, the elements of the DCS are polymorphic. Some of them have an apical tuft of rigid microvilli (brush cells). Other elements have secretory exocrine granules and others may have endocrine differentiation. Often these elements are innervated. To date, the functional role for the DCS is unknown also if several hypotheses have been adv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemosensory Clusters
{{Short description, Aggregates of chemoreceptor cells Chemosensory clusters are aggregates formed by a small number of chemoreceptor cells with characteristics similar to those found in the taste cells of the oropharyngeal cavity. The chemosensory clusters are similar to the taste buds but are smaller, resembling the developing taste buds. Chemosensory clusters are located in the larynx distally to the portion in which are present laryngeal taste buds and proximally to the region in which solitary chemosensory cells are found. Rarely, chemosensory clusters may be found in the distal portion of the airway. The elements forming the chemosensory clusters share common morphological and biochemical characteristics with the taste cells located in taste buds of the oropharyngeal cavity. In particular, they may express molecules of the chemoreceptorial cascade (e.g. trans-membrane taste receptors, the G-protein G proteins, also known as guanine nucleotide-binding proteins, are a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sensory Systems
The sensory nervous system is a part of the nervous system responsible for processing sense, sensory information. A sensory system consists of sensory neurons (including the sensory receptor cells), neural pathways, and parts of the brain involved in sensory perception. Commonly recognized sensory systems are those for Vision (sense), vision, Auditory system, hearing, somatic sensation, touch, taste, olfaction, smell, and Vestibular system, balance. Senses are transducers from the physical world to the realm of the mind where people interpret the information, creating their perception of the world around them. The receptive field is the area of the body or environment to which a receptor organ and receptor cells respond. For instance, the part of the world an eye can see, is its receptive field; the light that each Rod cell, rod or Cone cell, cone can see, is its receptive field. Receptive fields have been identified for the visual system, auditory system and somatosensory sys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
