- The basic structural and functional unit in people and all living things. Each cell is a small container of chemicals and water wrapped in a membrane. Each cell in the human body — there are 100 trillion cells in each of us — contains the entire human genome, all the genetic information necessary to build a human being. This information is encoded within the cell nucleus in 6 billion base pairs, subunits of DNA, packaged in 23 pairs of chromosomes, one chromosome in each pair coming from each parent. Each of the 46 human chromosomes contains the DNA for thousands of individual genes, the units of heredity. There are notable exceptions including the egg and sperm cells (each of which have only 23 chromosomes containing half the usual amount of DNA) and mature red blood cells (which no longer have a nucleus and so lack chromosomes and DNA).
* * *1. The smallest unit of living structure capable of independent existence, composed of a membrane-enclosed mass of protoplasm and containing a nucleus or nucleoid. Cells are highly variable and specialized in both structure and function, though all must at some stage replicate proteins and nucleic acid s, utilize energy, and reproduce themselves. 2. A small closed or partly closed cavity; a compartment or hollow receptacle. 3. A container of glass, ceramic, or other solid material within which chemical reactions generating electricity take place or solutions are placed for photometric assays. [L. cella, a storeroom, a chamber]- absorption c. a small glass chamber with parallel sides, in which absorption spectra of solutions can be obtained.- absorptive cells of intestine cells on the surface of villi of the small intestine and the luminal surface of the large intestine that are characterized by having microvilli on their free surface.- accessory c. SYN: antigen-presenting cells.- acinar c. any secreting c. lining an acinus, especially applied to the cells of the pancreas that furnish pancreatic juice and enzymes to distinguish them from the cells of ducts and the islets of Langerhans. SYN: acinous c..- adipose c. SYN: fat c..- alpha cells of anterior lobe of hypophysis acidophil cells that constitute about 35% of the cells of the anterior lobe. There are two varieties: one that elaborates somatotropin, another that elaborates prolactin.- alveolar c. any of the cells lining the alveoli of the lung, including the squamous alveolar cells, the great alveolar cells, and the alveolar macrophages. SYN: pneumocyte.- amacrine c. a nerve c. with short branching dendrites but believed to lack an axon; Cajal described and named such cells in the retina.- ameboid c. a c. such as a leukocyte, having ameboid movements, with a power of locomotion. SYN: wandering c.. SYN: migratory c..- amniogenic cells cells from which the amnion develops.- anabiotic c. c. that is capable of resuscitation after apparent death; the existence of anabiotic tumor cells is postulated to explain the recurrence of a cancer after a very long symptomless period following operation.- anaplastic c. 1. a c. that has reverted to an embryonal state; 2. an undifferentiated c., characteristic of malignant neoplasms.- angioblastic cells those cells in the early embryo from which primitive blood cells and endothelium develop.- anterior ethmoidal cells [TA] the anterior group of air cells of the ethmoidal sinuses; each sinus communicates with the middle meatus of the nasal cavity. SYN: cellulae ethmoidales anteriores [TA], anterior cells, anterior ethmoidal air cells, anterior sinuses, sinus ethmoidales anteriores.- antigen-presenting cells (APC) cells that process protein antigens into peptides and present them on their surface in a form that can be recognized by lymphocytes. APCs include Langerhans fol=inflect>cells, dendritic cells, macrophages, B cells, and in humans, activated T cells. SYN: accessory c..- antigen-responsive c. SYN: antigen-sensitive c..- antigen-sensitive c. a small lymphocyte that, although not itself an immunologically activated c., responds to antigenic (immunogenic) stimulus by a process of division and differentiation that results in the production of immunologically activated cells. SYN: antigen-responsive c..- argentaffin cells cells that contain granules which precipitate silver from an ammoniacal silver nitrate solution. SEE ALSO: enteroendocrine cells.- argyrophilic cells cells that bind silver salts but that precipitate silver only in the presence of a reducing agent. SEE ALSO: enteroendocrine cells.- Aschoff c. a large c. component of rheumatic nodules in the myocardium with a characteristic nucleus and relatively little cytoplasm.- Askanazy c. SYN: Hürthle c..- atypical glandular cells of undetermined significance the term in the Bethesda system for reporting cervical and/or vaginal cytologic diagnosis describing cells that show either endometrial or endocervical differentiation and display nuclear atypia that exceed reactive or reparative changes but lack definite features of invasive adenocarcinoma. SEE ALSO: Bethesda system.- atypical squamous cells of undetermined significance (ASCUS) the term in the Bethesda system for reporting cervical/vaginal cytologic diagnosis describing cellular abnormalities that are more marked than those attributable to reactive changes but that quantitatively or qualitatively fall short of a definitive diagnosis of squamous intraepithelial lesion (LSIL); may reflect a benign or a potentially serious lesion. SEE ALSO: Bethesda system, reactive changes, under change.- auditory receptor cells columnar cells in the epithelium of the organ of Corti, having hairs (stereocilia) on their apical ends. See Corti cells.- balloon c. 1. an unusually large degenerated c. with pale-staining vacuolated or reticulated cytoplasm, as in viral hepatitis or in degenerated epidermal cells in herpes zoster; 2. a large form of nevus c. with abundant nonstaining cytoplasm, formed by vacular degeneration of melanosomes.- band c. any c. of the granulocytic (leukocytic) series that has a nucleus that could be described as a curved or coiled band, no matter how marked the indentation, if it does not completely segment the nucleus into lobes connected by a filament. SYN: band neutrophil, rod nuclear c., Schilling band c., stab c., stab neutrophil, staff c..- basket c. 1. a neuron enmeshing the c. body of another neuron with its terminal axon ramifications; 2. SYN: smudge cells. 3. a myoepithelial c. with branching processes that occurs basal to the secretory cells of certain salivary gland and lacrimal gland alveoli.- beaker c. SYN: goblet c..- beta c. of anterior lobe of hypophysis one of a population of functionally diverse cells that contain basophilic granules and secrete hormones such as ACTH, lipotropin, thyrotropin, and the gonadotropins. SYN: basophil c. of anterior lobe of hypophysis.- Betz cells large pyramidal cells in the motor area of the precentral gyrus of the cerebral cortex. SYN: Bevan-Lewis cells.- bipolar c. a neuron having two processes, such as those of the retina or the spiral and vestibular ganglia of the eighth nerve.- Bowenoid cells cells characteristic of Bowen disease; scattered large, round intraepidermal keratinocytes with a hyperchromatic nucleus and pale cytoplasm.- bristle c. hair c. of the inner ear.- bronchic cells SYN: pulmonary alveolus.- C c. 1. a c. of the pancreatic islets of the guinea pig; SYN: gamma c. of pancreas. SEE ALSO: medullary carcinoma of thyroid. 2. calcitonin-secreting round or spindle shaped follicular thyroid c.; ultrastructurally contains numerous 60–550 nm neuroendocrine granules; best identified immunohistochemically with antibodies to calcitonin. SYN: light cells of thyroid, parafollicular cells.- Cajal c. 1. SYN: horizontal c. of Cajal. 2. SYN: astrocyte.- caliciform c. SYN: goblet c..- castration cells altered basophilic cells of the anterior lobe of the pituitary that develop following castration; the body of the c. is occupied by a large vacuole that displaces the nucleus to the periphery, giving the c. a resemblance to a signet ring. SYN: signet ring cells.- centroacinar c. a c. of the pancreatic ductule that occupies the lumen of an acinus; it secretes bicarbonate and water, providing an alkaline pH necessary for enzyme activity in the intestine.- chalice c. SYN: goblet c..- chief c. of parathyroid gland a round clear c. with a centrally located nucleus; secretes parathyroid hormone.- chromaffin c. a c. that stains with chromic salts, in adrenal medulla and paraganglia of the sympathetic nervous system.- chromophobe cells of anterior lobe of hypophysis cells of the adenohypophysis that are devoid of specific acidophilic or basophilic granules when stained with common differential stains.- Clara c. a rounded, club-shaped, nonciliated c. protruding between ciliated cells in bronchiolar epithelium; believed to be secretory in function. SYN: bronchiolar exocrine c..- Clarke cells large multipolar cells characteristic of the thoracic nucleus (Clarke nucleus in lamina VII) of the spinal cord.- Claudius cells columnar cells on the floor of the ductus cochlearis external to the organ of Corti.- clear c. 1. a c. in which the cytoplasm appears empty with the light microscope, as occurs in certain secretory cells of eccrine sweat glands and in the parathyroid glands when the glycogen is unstained; 2. any c., particularly a neoplastic one, containing abundant glycogen or other material that is not stained by hematoxylin or eosin, so that the c. cytoplasm is very pale in routinely stained sections.- clonogenic c. a c. that has the potential to proliferate and give rise to a colony of cells; some daughter cells from each generation retain this potential to proliferate.- clue c. a type of vaginal epithelial c. that appears granular and is coated with coccobacillary organisms; seen in bacterial vaginosis.- cochlear hair cells sensory cells in the organ of Corti in synaptic contact with sensory as well as efferent fibers of the cochlear (auditory) nerve; from the apical end of each c. about 100 stereocilia extend from the surface and make contact with the tectorial membrane. SYN: Corti cells.- column cells neurons in the gray matter of the spinal cord whose axons are confined within the central nervous system.- commissural c. a neuron whose axon passes to the opposite side of the neuraxis. SYN: heteromeric c..- contrasuppressor cells a subpopulation of T cells, distinct from T helper cells, which allegedly inhibit T suppressor c. function.- crescent c. SYN: sickle c..- cytomegalic cells cells containing large intranuclear and intracytoplasmic cytomegalic inclusion bodies caused by cytomegalovirus; a member of the family Herpesviridae.- cytotoxic c. 1. a subset of CD8 T lymphocytes that bind to other cells via class I MHC and are involved in their destruction. SYN: T cytotoxic cells. 2. other cells of the immune system capable of killing pathogens or abberant cells, i.e., macrophages, NK cells, K cells.- cytotrophoblastic cells stem cells that fuse to form the overlying syncytiotrophoblast of placental villi. SYN: Langhans cells (2).- decoy c. benign exfoliated epithelial c. with pyknotic nucleus seen in urinary infections; may be mistaken for malignant c..- delta c. of pancreas a c. of the islets having fine granules and containing somatostatin. SYN: D c..- dust c. SYN: alveolar macrophage.- effector c. a terminally differentiated leukocyte that performs one or more specific functions. SEE ALSO: effector.- egg c. the unfertilized ovum.- endodermal c. embryonic cells forming the yolk sac and giving rise to the epithelium of the alimentary and respiratory tracts and to the parenchyma of associated glands. SYN: entodermal c..- endothelial c. one of the squamous cells forming the lining of blood and lymph vessels and the inner layer of the endocardium. SYN: endotheliocyte.- enterochromaffin cells SYN: enteroendocrine cells.- enteroendocrine cells cells, scattered throughout the digestive tract that are of several varieties and are believed to produce at least 20 different gastrointestinal hormones and neurotransmitters; they contain granules that may be either argentaffinic or argyrophilic. SYN: enterochromaffin cells, Kulchitsky cells.- entodermal c. SYN: endodermal c..- ependymal c. a c. lining the central canal of the spinal cord (those of pyramidal shape) or one of the brain ventricles (those of cuboidal shape).- epithelial reticular c. one of the many-branched epithelial cells that collectively form the supporting stroma for lymphocytes in the thymus; believed to produce thymosin and other factors that control thymic function.- epithelioid c. 1. a nonepithelial c. having certain characteristics of epithelium; 2. large mononuclear histiocytes having certain epithelial characteristics, particularly in areas of granulomatous inflammation where they are polygonal and have eosinophilic cytoplasm.- ethmoid cells ethmoidal air cells; evaginations of the mucous membrane of the middle and superior meatuses of the nasal cavity into the ethmoidal labyrinth forming multiple small paranasal sinuses; they are subdivided into anterior, middle and posterior ethmoidal sinuses. See anterior ethmoidal cells, middle ethmoidal cells, posterior ethmoidal cells. SYN: cellulae ethmoidales [TA], ethmoid air cells [TA], ethmoidal cells [TA], antra ethmoidalia, ethmoidal sinuses, sinus ethmoidales.- fasciculata c. a c. of the zona fasciculata of the adrenal cortex that contains numerous lipid droplets due to the presence of corticosteroids.- fat c. a connective tissue c. distended with one or more fat globules, the cytoplasm usually being compressed into a thin envelope, with the nucleus at one point in the periphery. SYN: adipocyte, adipose c..- fat-storing c. a multilocular fat-filled c. present in the perisinusoidal space in the liver. SYN: lipocyte.- Ferrata c. SYN: hemohistioblast.- flame c. primitive, ciliated excretory c. in trematodes; the movement of the cilia on this c. within the miracidium larva within a schistosome egg indicates egg viability.- foam cells cells with abundant, pale-staining, finely vacuolated cytoplasm, usually histiocytes that have ingested or accumulated material that dissolves during tissue preparation, especially lipids. SEE ALSO: lipophage.- follicular ovarian cells cells of an ovarian follicle that surround the developing ovum; they form the stratum granulosum ovarii and cumulus oophorus.- foreign body giant c. a multinucleate “c.” or syncytium formed around particulate matter in chronic inflammatory reactions, formed by a fusion of macrophages.- formative c. inner c. mass c. of the blastocyst; collectively, these cells give rise to the embryo.- G cells enteroendocrine cells that secrete gastrin, found primarily in the mucosa of the pyloric antrum of the stomach.- ganglion c. originally, any nerve c. (neuron); in current usage, a neuron the c. body of which is located outside the limits of the brain and spinal cord, hence forming part of the peripheral nervous system; ganglion cells are either 1) the pseudounipolar cells of the sensory spinal and cranial nerves (sensory ganglia), or 2) the peripheral multipolar motor neurons innervating the viscera (visceral or autonomic ganglia). SYN: gangliocyte.- ganglion cells of dorsal spinal root pseudounipolar nerve c. bodies in the ganglia of the dorsal spinal nerve roots; the sensory spinal nerves are composed of the peripheral axon branches of these sensory ganglion cells, whereas the central axon branch of each such c. enters the spinal cord as a component of the dorsal root.- ganglion cells of retina the nerve cells of the retina whose central processes (axons) form the optic nerve; their peripheral processes synapse with the bipolar cells and through them with the rod and cone cells; these c. bodies are round or flask-shaped and vary considerably in size. SEE ALSO: ganglionic layer.- Gaucher cells large, finely and uniformly vacuolated cells derived from the reticuloendothelial system, and found especially in the spleen, lymph node s, liver, and bone marrow of patients with Gaucher disease; Gaucher cells contain kerasin (a cerebroside), which accumulates as a result of a genetically determined absence of the enzyme glucosylceramidase.- gemistocytic c. SYN: gemistocytic astrocyte.- germ c. SYN: sex c..- ghost c. 1. a dead c. in which the outline remains visible, but without other cytoplasmic structures or stainable nucleus; 2. an erythrocyte after loss of its hemoglobin.- giant c. a c. of large size, often with many nuclei.- Gierke cells small cells characteristic of the substantia gelatinosa (lamina II) of the dorsal horn of the spinal cord.- gitter c. a lipid-laden microglial phagocyte commonly seen at the edge of healing brain infarcts, a result of cellular phagocytosis of lipid from necrotic or degenerating brain cells. SYN: compound granule c., gitterzelle. [Ger. Gitterzelle, fr. Gitter, lattice, wire-net]- glitter cells polymorphonuclear leukocytes that stain pale blue with gentian violet and contain cytoplasmic granules that exhibit brownian movement; observed in urine sediment and characteristic of pyelonephritis.- globoid c. a large c. of mesodermal origin that is found clustered in the intracranial tissues in globoid c. leukodystrophy.- glomerulosa c. a c. of the zona glomerulosa of the adrenal cortex that is the source of aldosterone; the cells are arranged in spherical or oval groups.- goblet c. an epithelial c. that becomes distended with a large accumulation of mucous secretory granules at its apical end, giving it the appearance of a goblet. SYN: beaker c., caliciform c., chalice c..- granule cells 1. small nerve c. bodies in the external and internal granular layers of the cerebral cortex; 2. small nerve c. bodies in the granular layer of the cerebellar cortex.- granulosa c. a c. of the membrana granulosa lining the vesicular ovarian follicle that becomes a luteal c. of the corpus luteum after ovulation.- granulosa lutein cells cells derived from the membrana granulosa of a mature ovarian follicle that secrete both estrogen and progesterone, and form the major component of the corpus luteum.- great alveolar cells cuboidal cells connected with the squamous pulmonary alveolar cells and having in their cytoplasm lamellated bodies (cytosomes) that represent the source of the surfactant that coats the alveoli. SYN: granular pneumonocytes, type II cells.- hair cells sensory epithelial cells present in the organ of Corti, in the maculae and cristae of the membranous labyrinth of the ear, and in taste buds; they are characterized by having long stereocilia or kinocilia (or both) which, with the light microscope, appear as fine hairs. SEE ALSO: vestibular hair cells, cochlear hair cells, taste cells.- hairy cells medium-sized leukocytes that have features of reticuloendothelial cells and multiple cytoplasmic projections (hairs) on the c. surface, but which may be a variety of B lymphocyte; they are found in hairy c. leukemia.- Haller c. a variant of ethmoidal air c. developing into the floor of the orbit adjacent to the natural ostium of the maxillary sinus. A diseased Haller c. is capable of obstructing that ostium and producing a maxillary sinusitis.- heart failure c. macrophage in the lung during left heart failure that often carries large amounts of hemosiderin. SEE ALSO: siderophore.- HeLa cells the first continuously cultured human malignant cells, derived from a cervical carcinoma of a patient, Henrietta Lacks; used in the cultivation of viruses.- helper cells SYN: T helper cells.- HEMPAS cells the abnormal erythrocytes of type II congenital dyserythropoietic anemia. See HEMPAS.- Hensen c. one of the supporting cells in the organ of Corti, immediately to the outer side of the cells of Deiters.- hilus cells cells in the hilus of the ovary that produce androgens; they are thought to be the ovarian counterpart of the interstitial cells of the testis. SYN: Berger cells.- hobnail c. c. characteristic of a clear c. adenocarcinoma; a round expansion of clear cytoplasm projects into the lumen of neoplastic tubules, but the basal part of the c. containing the nucleus is narrow.- Hofbauer c. a large c. in the connective tissue of the chorionic villi; it appears to be a type of phagocyte.- horizontal c. of Cajal a small fusiform c. found in the superficial layer of the cerebral cortex with its long axis placed horizontally. SYN: Cajal c. (1).- horizontal cells of retina cells in the outer part of the inner nuclear layer of the retina that lie with their axes more or less parallel with the surface. They are thought to connect the rods of one part of the retina with cones of another part.- Hürthle c. a large, granular eosinophilic c. derived from thyroid follicular epithelium by accumulation of mitochondria, e.g., in Hashimoto disease. SYN: Askanazy c..- I c. a cultured skin fibroblast containing membrane-bound inclusions; characteristic of mucolipidosis II. SYN: inclusion c..- immunologically activated c. an immunocyte that is in an elevated state of reactivity capable of carrying out an immune response.- immunologically competent c. a small lymphocyte capable of being immunologically activated by exposure to a substance that is antigenic (immunogenic) for the respective c.; activation involves either the capacity to produce antibody or the capacity to participate in c.-mediated immunity.- inclusion c. SYN: I c..- indifferent c. an undifferentiated, nonspecialized c..- innocent bystander c. the destruction of a c. by an immune process even though that c. was not directly targeted.- interdigitating reticulum c. an antigen-presenting c. in the paracortex of lymph node s, interacting with T lymphocytes.- interstitial cells 1. cells between the seminiferous tubules of the testis that secrete testosterone; SYN: Leydig cells. 2. cells derived from the theca interna of atretic follicles of the ovary; they resemble luteal cells and are an important source of estrogens; 3. pineal cells similar to glial cells with long processes.- irritation c. SYN: Türk c..- Jurkat cells a line of T cells often employed in immunologic research, originally derived from a Burkitt lymphoma.- juvenile c. SYN: metamyelocyte.- juxtaglomerular cells cells, located at the vascular pole of the renal corpuscle that secrete renin and form a component of the juxtaglomerular complex; they are modified smooth muscle cells primarily of the afferent arteriole of the renal glomerulus. SYN: Goormaghtigh cells.- K cells SYN: killer cells.- killer cells cytotoxic cells involved in antibody-dependent c.-mediated immune responses; they may be T lymphocytes with receptors for the Fc portion of IgG molecules, and lyse or damage IgG coated target cells without mediation of complement. See antibody-dependent c.-mediated cytotoxicity. SYN: K cells, null cells (1).- Kulchitsky cells SYN: enteroendocrine cells.- Kupffer cells phagocytic cells of the mononuclear phagocyte series found on the luminal surface of the hepatic sinusoids. SYN: stellate cells of liver.- lacis c. (lah-se′) one of the cells of the juxtaglomerular apparatus found at the vascular pole of the renal corpuscle. [Fr. lacis, meshwork]- Langerhans cells 1. dendritic clear cells in the epidermis, containing distinctive granules that appear rod- or racket-shaped in section, but lacking tonofilaments, melanosomes, and desmosomes; they carry surface receptors for immunoglobulin (Fc) and complement (C3), and are believed to be antigen fixing and processing cells of monocytic origin; active participants in cutaneous delayed hypersensitivity. 2. cells seen in eosinophilic granuloma and lymphoma of the lungs.- Langhans cells 1. multinucleated giant cells seen in tuberculosis and other granulomatous diseases; the nuclei are arranged in an arciform manner at the periphery of the cells; SYN: Langhans-type giant cells. 2. SYN: cytotrophoblastic cells.- LE c. a polymorphonuclear leukocyte containing an amorphous round body that is a phagocytosed nucleus from another c. plus serum antinuclear globulin (IgG) and complement; formed in vitro in the blood of patients with systemic lupus erythematosus. SYN: lupus erythematosus c..- Leishman chrome cells basophilic granular leukocytes (basophils) observed in the circulating blood of some persons with blackwater fever.- lepra cells distinctive, large, mononuclear phagocytes (macrophages) with a foamlike cytoplasm, and also poorly staining saclike structures resulting from degeneration of such cells, observed characteristically in leprous inflammatory reactions; indistinct staining results from numerous, fairly closely packed leprosy bacilli, which are acid-fast and resistant to staining by ordinary methods.- lining c. SYN: littoral c..- Lipschütz c. SYN: centrocyte (1).- littoral c. the cells lining the lymphatic sinuses of lymph node s and the blood sinuses of bone marrow. SYN: lining c.. [L. littoralis, the seashore]- lupus erythematosus c. SYN: LE c..- luteal c., lutein c. a c. of the corpus luteum of the ovary that is derived from the granulosa cells of the preovulatory follicle; it secretes progesterone and estrogen.- M c. SYN: microfold c..- Martinotti c. a small multipolar nerve c. with short branching dendrites scattered through various layers of the cerebral cortex; its axon ascends toward the surface of the cortex.- mast c. a connective tissue c. that contains coarse, basophilic, metachromatic secretory granules; the granules contain heparin, histamine and eosinophilic chemotactic factor. These cells are involved in immediate hypersensitivity reactions and play a role in the regulation of the composition of ground substance. SYN: granule c. of connective tissue, labrocyte, mastocyte, tissue basophil.- mastoid cells [TA] numerous small intercommunicating cavities in the mastoid process of the temporal bone that empty into the mastoid or tympanic antrum. SYN: cellulae mastoideae [TA], mastoid air cells, mastoid sinuses.- memory B cells b lymphocytes that mediate immunologic memory; these allow for enhanced immunologic reaction when an immunologically competent organism is reexposed to an antigen.- memory T cells t lymphoctyes that mediate immunologic memory; these allow for enhanced immunologic reaction when an immunologically competent organism is reexposed to an antigen.- mesangial c. a phagocytic c. in the capillary tuft of the renal glomerulus, interposed between endothelial cells and the basement membrane in the central or stalk region of the tuft. SYN: deep c., intercapillary c..- mesenchymal cells fusiform or stellate cells found between the ectoderm and endoderm of young embryos; the shape of the cells in fixed material is indicative of the fact that in life they were moving from their place of origin to areas where they would become reaggregated and specialized; most mesenchymal cells are derived from mesoderm, but in the cephalic region they also develop from neural crest or surface ectoderm; they are the most strikingly pluripotential cells in the embryonic body, developing at different locations into any of the types of connective or supporting tissues, to smooth muscle, to vascular endothelium, and to blood cells.- mesoglial cells SYN: mesoglia.- mesothelial c. one of the flat cells of mesodermal origin that form the superficial layer of the serosal membranes lining the body cavities of the abdomen and thorax.- Mexican hat c. SYN: target c. (1).- Meynert cells solitary pyramidal cells found in the cortex in the region of the calcarine fissure.- microfold c. specialized intestinal epithelial cells found in association with the lymphoid follicles in Peyer patches of the ileum; characterized by elaborate invaginations of their apical c. surface that harbor numerous lymphocytes and macrophages; believed to phagocytose antigens and present them to underlying lymphoid cells. SYN: M c..- middle ethmoidal cells [TA] the middle group of air cells of the ethmoidal sinuses; each sinus communicates with the middle meatus of the nasal cavity. SYN: cellulae ethmoidales mediae [TA], middle cells, middle ethmoidal air cells, middle ethmoidal sinuses, sinus ethmoidales mediae.- midget bipolar cells bipolar cells in the inner nuclear layer of the retina that synapse with individual cone cells in the outer plexiform layer; other larger bipolar cells in the inner nuclear layer synapse with both rod and cone cells; the axons of both types synapse in the inner plexiform layer with the dendrites of the ganglion cells.- migratory c. SYN: ameboid c..- Mikulicz cells foamy macrophages containing Klebsiella rhinoscleromatis; found in the mucosal nodules in rhinoscleroma.- mirror-image c. 1. a c. whose nuclei have identical features and are placed in the cytoplasm in similar fashion; 2. a binucleate form of Reed-Sternberg c. often found in Hodgkin disease; the twin nuclei are disposed in relation to an imaginary plane between them like a single nucleus together with its image in a mirror.- mitral cells large nerve cells in the olfactory lobe of the brain whose dendrites synapse (in glomeruli) with axons of the olfactory receptor cells of the nasal mucous membrane, and whose axons pass centrally in the olfactory tract to the olfactory cortex.- mossy c. one of the two types of neuroglia cells, consisting of a rather large body with numerous short branching processes.- mother c. a c. which, by division, gives rise to two or more daughter cells. SYN: brood c., metrocyte, parent c..- motor c. a neuron whose axon innervates peripheral effector cells such as muscle fibers or gland cells.- mucoalbuminous cells SYN: mucoserous cells.- mucoserous cells glandular cells intermediate in histologic characteristics between serous and mucous cells. SYN: mucoalbuminous cells, seromucous cells.- Müller radial cells SYN: Müller fibers (2), under fiber.- myeloid c. specifically, any young c. that develops into a mature granulocyte of blood, but frequently used as a synonym for marrow c..- myoepithelial c. a smooth muscle-like c. of ectodermal origin, found between the epithelium and basement membrane in a number of organs such as mammary, sweat, and lacrimal glands.- myoid cells flattened smooth muscle-like cells of mesodermal origin that lie just outside the basal lamina of the seminiferous tubule. SYN: peritubular contractile cells.- Nageotte cells cells found in the cerebrospinal fluid, one or two per cubic millimeter in health, but in greater numbers in various diseases.- natural killer cells large granular lymphocytes which do not express markers of either T or B c. lineage. These cells do possess Fc receptors for IgG and can kill target cells using antibody-dependent c.-mediated cytotoxicity. NK cells can also use perforin to kill cells in the absence of antibody. Killing occurs without previous sensitization. SYN: NK cells.- neuroendocrine transducer c. an endocrine c. that releases its hormonal product into the bloodstream only upon receipt of a nervous impulse.- neurosecretory cells nerve cells, such as those of the hypothalamus, that elaborate a chemical substance (such as a releasing factor, neuropeptide, or, more rarely, a true hormone) that influences the activity of another structure ( e.g., anterior lobe of the hypophysis). See also neurosecretion.- nevus c. the c. of a pigmented cutaneous nevus that differs from a normal melanocyte in that it lacks dendrites. SYN: nevocyte.- nevus c., A-type melanocytes in the epidermis in pigmented nevi, resembling epithelial cells and frequently containing melanin.- NK cells SYN: natural killer cells.- nonclonogenic c. a c. that does not give rise to a colony of cells (large numbers of cells that are genetically identical); may undergo two or more c. divisions, but all daughter cells are destined to die or differentiate (losing all potential to divide).- null cells 1. SYN: killer cells. 2. large granular lymphocytes that lack surface markers or membrane-associated proteins of either B or T lymphocytes.- oat c. SYN: small c..- OKT cells old term for cells recognized by monoclonal antibodies to T lymphocyte antigens; OKT-3 cells are T lymphocytes as a class, because all share a common leukocyte differentiation antigen; OKT-4 cells are helper cells; OKT-8 cells are suppressor cells. OKT-4/OKT-8 expresses the ratio of helper to suppressor cells, sometimes used as a measure of the functional status of the immune system and thus a basis for clinical diagnosis and prognosis. Current usage favors using CD designations. [Ortho-Kung T c.]- olfactory receptor cells very slender nerve cells, with large nuclei and surmounted by six to eight long, sensitive cilia in the olfactory epithelium at the roof of the nose; they are the receptors for smell. SYN: olfactory cells, Schultze cells.- Onodi c. a variant of a posterior ethmoidal air c. in intimate relationship with the optic nerve just distal to the optic chiasm.- Opalski c. a characteristically altered glial c. in the basal ganglia and thalamus in hepatocerebral degeneration and Wilson disease.- osteochondrogenic c. one of the undifferentiated cells in the inner layer of the periosteum of an endochondrally developing bone capable of developing into an osteoblast or a chondroblast.- oxyphil c. c. of the parathyroid gland that increase in number with age; the cytoplasm contains numerous mitochondria and stains with eosin. Similar cells, and tumors composed of them, are found in salivary glands and the thyroid; in the latter, also called Hürthle c..- P c. a characteristic specialized c., with probable pacemaker function, found in the S-A node and A-V junction.- packed human blood cells whole blood from which plasma has been removed; may be prepared any time during the dating period of the whole blood from which it is derived, but not later than 6 days after the blood has been drawn if separation of plasma and cells is achieved by centrifugation.- Paget cells relatively large, neoplastic epithelial cells (carcinoma cells) with hyperchromatic nuclei and abundant palely staining cytoplasm; in Paget disease of the breast, such cells occur in neoplastic epithelium in the ducts and in the epidermis of the nipple, areola, and adjacent skin.- pagetoid cells atypical melanocytes resembling Paget cells, q.v., found in some cutaneous melanomas of the superficial spreading type.- Paneth granular cells cells, located at the base of intestinal glands of the small intestine, which contain large acidophilic refractile granules and may produce lysozyme. SYN: Davidoff cells.- parafollicular cells SYN: C c. (2).- paraganglionic cells cells of the embryonic sympathetic nervous system that become chromaffin cells.- parietal c. one of the cells of the gastric glands; it lies upon the basement membrane, covered by the chief cells, and secretes hydrochloric acid that reaches the lumen of the gland through fine intracellular and intercellular canals (canaliculi). SYN: acid c., oxyntic c..- pericapillary c. SYN: pericyte.- peripolar c. a granular c. located where the parietal and visceral capsules of the renal corpuscle meet; part of the c. faces the filtration space of Bowman.- perithelial c. SYN: pericyte.- permissive c. a c. in which the late phase of viral infection follows the early phase and c. death is coupled with massive synthesis of virus; E.G., monkey cells are permissive for SV40.- pessary c. a red blood c. in which the hemoglobin has disappeared from the center, leaving only the periphery visible.- phalangeal c. the supporting cells of the organ of Corti, attached to the basement membrane and receiving the hair cells between their free extremities. SEE ALSO: phalanx (2). SYN: Deiters cells (1).- photo c. a light-detecting electronic device used to measure x-ray transmission through a patient for automatic termination of the exposure or to calculate a digital image.- physaliphorous c. cells containing a bubbly or vacuolated cytoplasm, e.g., as characteristically seen in chordoma.- Pick c. a relatively large, rounded or polygonal, mononuclear c., with indistinctly or palely staining, foamlike cytoplasm that contains numerous droplets of a phosphatide, sphingomyelin; such cells are widely distributed in the spleen and other tissues, especially those rich in reticuloendothelial components, in patients with Niemann-Pick disease. SYN: Niemann-Pick c..- pigment cells of iris cells of the stromal layer of the iris; in dark eyes (but not in blue) they contain granules of pigment.- pillar cells cells forming the outer and inner walls of the tunnel in the organ of Corti. SYN: Corti pillars, Corti rods, pillar cells of Corti, tunnel cells.- plasma c. an ovoid c. with an eccentric nucleus; the cytoplasm is strongly basophilic because of the abundant RNA in its endoplasmic reticulum; plasma cells are derived from B lymphocytes and are active in the formation and secretion of antibodies. SYN: plasmacyte.- pluripotent cells primordial cells that may still differentiate into various specialized types of tissue elements; e.g., mesenchymal cells.- polychromatic c. a primitive erythrocyte in bone marrow, with basophilic material as well as hemoglobin (acidophilic) in the cytoplasm. SYN: polychromatophil c..- polychromatophil c. SYN: polychromatic c..- posterior ethmoidal cells [TA] the posterior group of air cells of the ethmoidal sinuses; each sinus communicates with the superior meatus of the nasal cavity. SYN: cellulae ethmoidales posteriores [TA], posterior cells, posterior ethmoidal air cells, sinus ethmoidales posteriores.- pregnancy cells hypophysial chromophobe cells that increase in number and accumulate eosinophil granules during pregnancy.- pregranulosa cells capsular cells surrounding the primordial ova in the embryonic ovary; they are derived from celomic epithelium.- prickle c. one of the cells of the stratum spinosum of the epidermis; so called because of typical shrinkage artifacts that occur in histologic preparations, resulting in intercellular bridges at points of desmosomal adhesion. SYN: spine c..- primitive reticular c. SYN: reticular c..- primordial c. a c. from a group that constitutes the primordium of an organ or part of the embryo.- primordial germ c. the most primitive undifferentiated sex c., found initially outside the gonad. SYN: gonocyte.- pseudo- Gaucher c. a plasma c., microscopically resembling a Gaucher c., found in the bone marrow in some cases of multiple myeloma.- pseudounipolar c. SYN: unipolar neuron.- pseudoxanthoma c. relatively large phagocytic cells (macrophages) that contain numerous small lipid vacuoles or hemosiderin (or both), in organizing hemorrhagic or inflammatory lesions.- pus c. SYN: pus corpuscle.- pyramidal cells neurons of the cerebral cortex which, in sections perpendicular to the cortical surface, exhibit a triangular shape with a long apical dendrite directed toward the surface of the cortex; there are also lateral dendrites, and a basal axon that descends to deeper layers.- pyrrol c., pyrrhol c. a c. of the mononuclear macrophage system that has a special affinity for pyrrol blue, taking up the dye by a process of pinocytosis.- Raji c. a c. of a cultured line of lymphoblastoid cells derived from a Burkitt lymphoma; it possesses numerous receptors for certain complement components and is thus suitable for use in detection of immune complexes. It expresses certain complement receptors as well as Fc receptors for immunoglobulin G.- reactive c. SYN: gemistocytic astrocyte.- Reed-Sternberg c. large transformed lymphocytes, probably B c. in origin, generally regarded as pathognomonic of Hodgkin lymphoma; a typical c. has a pale-staining acidophilic cytoplasm and one or two large nuclei showing marginal clumping of chromatin and unusually conspicuous deeply acidophilic nucleoli; binucleate Reed-Sternberg c. frequently shows a mirror-image form (mirror-image c.). SYN: Reed c., Sternberg c., Sternberg-Reed c..- Renshaw cells inhibitory interneurons that are innervated by collaterals from motoneurons and in turn form synapses with the same and adjacent motoneurons to exert inhibition; identified physiologically and by intracellular injection technic.- resting wandering c. SYN: fixed macrophage.- reticular c. c. with processes making contact with those of other similar cells to form a cellular network ensheathing a network of reticular fibers, which constitutes the stroma of all lymphoid organs except the thymus. SYN: primitive reticular c..- rhagiocrine c. SYN: macrophage.- Rieder cells abnormal myeloblasts (12 to 20 μm in diameter) in which the nucleus may be widely and deeply indented ( i.e., suggestive of lobulation), or may actually be a bi- or multilobate structure; such cells are frequently observed in acute leukemia, and probably represent a more rapid maturation of the nucleus than that of the cytoplasm.- rosette-forming cells term usually used for T lymphocytes with an affinity for sheep erythrocytes and which, when suspended in serum, bind the uncoated, nonsensitized erythrocytes in a rosette formation.- sarcogenic c. SYN: myoblast.- satellite cells neuroglial cells surrounding the c. body of a ganglion c. in the spinal, cranial, and autonomic ganglia.- satellite c. of skeletal muscle an elongated spindle-shaped c. occupying depressions in the sarcolemma and between it and the basal lamina; believed to play a role in muscle repair and regeneration by fusing with adjacent myofiber. SYN: sarcoplast.- scavenger c. SYN: phagocyte.- Schwann cells cells of ectodermal (neural crest) origin that compose a continuous envelope around each nerve fiber of peripheral nerves; such cells are comparable to the oligodendroglia cells of brain and spinal cord; like the latter, they may form membranous expansions that wind around axons and thus form the axon's myelin sheath. SYN: neurilemma cells, neurolemma cells.- segmented c. a polymorphonuclear leukocyte matured beyond the band c. so that two or more lobes of the nucleus occur.- sensitized c. 1. a c. that has been either exposed to antigen or opsonized with antibodies and/or complement. 2. a small, “committed,” c. derived, by division and differentiation, from a resting lymphocyte; 3. a c., including a bacterial c., that has combined with specific antibody to form a complex capable of reacting with complement components;- sensory c. a c. in the peripheral nervous system that receives afferent (sensory) input; sensory receptor cells.- serous c. a c., especially of the salivary gland, that secretes a watery or thin albuminous fluid, as opposed to a mucous c.. SYN: albuminous c. (1).- Sertoli cells elongated cells in the seminiferous tubules that ensheathe spermatids, providing a microenvironment that supports spermiogenesis; they secrete androgen-binding protein and establish the blood-testis barrier by forming tight junctions with adjacent Sertoli cells. SYN: nurse cells.- Sézary c. an atypical T lymphocyte seen in the peripheral blood in the Sézary syndrome; it has a large convoluted nucleus and scanty cytoplasm containing PAS-positive vacuoles.- shadow cells SYN: smudge cells.- sickle c. an abnormal, crescentic erythrocyte that is characteristic of sickle c. anemia, resulting from an inherited abnormality of hemoglobin (hemoglobin S) causing decreased solubility at low oxygen tension. SYN: crescent c., drepanocyte, meniscocyte.- silver c. one of a number of cells seen in plaques of multiple sclerosis, having round or oval nuclei, the body of the c. containing many yellow or light brown particles; the cells are characteristic of multiple sclerosis, but are found in other conditions, including syphilis.- small c. a short, blunty spindle-shaped c. that contains a relatively large, hyperchromatic nucleus, frequently observed in some forms of undifferentiated bronchogenic carcinoma. SYN: oat c..- small cleaved c. a lymphoid c. of follicular center c. origin that has an irregularly shaped nucleus with clumped chromatin, absent nucleoli, and one or more clefts in the nuclear membrane.- smudge cells immature leukocytes of any type that have undergone partial breakdown during preparation of a stained smear or tissue section, because of their greater fragility; smudge cells are seen in largest numbers in chronic lymphocytic leukemia. SYN: basket c. (2), Gumprecht shadows, shadow cells.- spider c. 1. SYN: astrocyte. 2. a c. in a rhabdomyoma of the heart, with central nucleus and cytoplasmic mass connected to the c. wall by strands of cytoplasm separated by clear glycogen-filled areas.- spine c. SYN: prickle c..- spur c. a spiculated red c. with 5–10 spiny projections of varying length distributed irregularly over the c. surface; seen in patients with liver disease and abetalipoproteinemia.- squamous alveolar cells highly attentuated squamous cells that form the gas-permeable epithelium lining the alveoli of the lungs. SYN: type I cells.- standard c. an electrical c. having a definite known voltage; used to calibrate other electric cells.- stellate cells of cerebral cortex small star-shaped cells in the second and fourth layers of the cortex, and large stellate cells in the deeper part of the third layer in the visual cortex.- strap c. an elongated tumor c. of uniform width that may show cross-striations; found in rhabdomyosarcoma.- supporting c. SYN: sustentacular c..- suppressor cells cells of the immune system that inhibit or help to terminate an immune response, e.g., suppressor macrophages and suppressor T cells.- surface mucous cells of stomach cells lining the gastric surface and foveolae; an acid-resistant mucous product at the apical end of each c. that apparently diffuses out to lubricate and protect the mucosal surface. SYN: theca cells of stomach.- sustentacular c. one of the ordinary elongated cells resting on the basement membrane that surround and serve as a support to the shorter specialized cells in certain organs, such as the labyrinth of the inner ear or olfactory epithelium. SYN: supporting c..- sympathicotropic cells large epithelioid cells in the hilum of the ovary associated with unmyelinated nerve fibers.- sympathochromaffin c. the c. type in the embryonic suprarenal gland from which both sympathetic ganglion cells and chromaffin cells are developed.- synovial c. fibrotoplastlike cells that form 1–6 epithelioid layers in the synovial membrane of joints; believed to contribute proteoglycans and hyaluronate to the synovial fluid.- T c. SYN: T lymphocyte.- tanned red cells erythrocytes subjected to mild treatment with chemicals such as tannic acid so that they adsorb onto their surface soluble antigens; used in hemagglutination tests.- target c. 1. an erythrocyte with a dark center surrounded by a light band that again is encircled by a darker ring; it thus resembles a shooting target; such cells appear in target-c. anemias or after splenectomy; SYN: Mexican hat c.. 2. a c. lysed by cytotoxic T lymphocytes, as in graft rejection.- taste cells darkly staining cells in a taste bud that appear to have extending into the gustatory pore long hairlike microvilli containing a number of closely packed microtubules; the taste cells stand in synaptic contact with sensory nerve fibers of the facial, glossopharyngeal, or vagus nerves. SYN: gustatory cells.- TDTH cells a functional subset of T helper cells that are involved in delayed-type hypersensitivity reactions.- theca lutein c. a steroid secretory c. of the corpus luteum that comes from the theca interna of the ovarian follicle at the time of ovulation and secretes progesterone under the control of prolactin. SYN: paraluteal c., paralutein c..- T helper cells (Th) a subset of lymphocytes that secrete various cytokines that regulate the immune response : subset 1, which synthesize gamma interferon and interleukin 2 and are involved in c.-mediated immunity; subset 2, which synthesize interleukins 4, 5, 10, and are involved in immunoglobulin synthesis. SYN: helper cells.- T helper subset 1 cells a subset of CD4+ T cells that can secrete interferon gamma and IL-2 and are responsible for cellular immunity.- T helper subset 2 cells a subset of CD4+ T cells that synthesize IL-4, IL-5, and IL-10 and facilitate immunoglobulin synthesis.- Tiselius electrophoresis c. the special container in a Tiselius apparatus containing the solution to be analyzed electrophoretically.- Toker c. an epithelial c. with clear cytoplasm found in 10% of normal nipples; contains keratin 7, like Paget carcinoma cells, from which it must be distinguished cytologically.- Touton giant c. a xanthoma c. in which the multiple nuclei are grouped around a small island of nonfoamy cytoplasm.- transducer c. any c. responding to a mechanical, thermal, photic, or chemical stimulus by generating an electrical impulse synaptically transmitted to a sensory neuron in contact with the c..- tubal air cells (of pharyngotympanic tube) [TA] occasional small air cells in the inferior wall of the pharyngotympanic tube, near the tympanic orifice, communicating with the tympanic cavity. SYN: cellulae pneumaticae tubae auditivae [TA], air cells of auditory tube.- tufted c. a particular type of c. in the olfactory bulb comparable to the bulb's mitral c. with respect to afferent and efferent relationships, but smaller and more superficially located.- Türk c. a relatively large, immature c. with certain morphologic features resembling those of a plasma c., although the nuclear pattern is similar to that of a myeloblast; found in circulating blood only in pathologic conditions. SYN: irritation c., Türk leukocyte.- tympanic cells [TA] numerous groovelike depressions in the walls of the tympanic cavity, communicating with the tubal air cells. SYN: cellulae tympanicae [TA], tympanic air cells.- undifferentiated c. a primitive c. that has not assumed the morphologic and functional characteristics it will later acquire.- veil c. an antigen-presenting c. that has veil-like cytoplasmic processes and circulates in the blood and lymph. SYN: veiled cells (1).- vestibular hair cells cells in the sensory epithelium of the maculae and cristae of the membranous labyrinth of the inner ear; afferent and efferent nerve fibers of the vestibular nerve end synaptically upon them; from the apical end of each c. a bundle of stereocilia and a kinocilium extend into the statoconial membrane of the maculae and the cupula of the cristae.- Virchow cells 1. the lacunae in osseous tissue containing the osteocytes; 2. an obsolete term for the osteocytes themselves; 3. SYN: corneal corpuscles, under corpuscle.- virus-transformed c. a c. that has been genetically changed to a tumor c., the change being subsequently transmitted to all descendent cells; cells transformed by oncogenic RNA viruses continue to produce virus in high concentration without being killed; DNA tumor virus-transformed cells develop (along with other changes) tumor-associated antigens and rarely produce virus.- vitreous c. a c. occurring in the peripheral part of the vitreous body that may be responsible for production of hyaluronic acid and possibly of collagen. SYN: hyalocyte.- Warthin-Finkeldey cells giant cells with multiple overlapping nuclei, found in lymphoid tissue in measles, especially during the prodromal stage.- wasserhelle c. SYN: water-clear c. of parathyroid.- water-clear c. of parathyroid a variety of chief c., so called because the cytoplasm contains much glycogen that is not preserved or stained in the usual preparation. SYN: wasserhelle c..- WI-38 cells the first normal human cells, derived from fetal lung tissue, continuously cultivated. [Wistar Institute]- yolk cells primitive embryonic cells lying between the endoderm and mesoderm; they probably give rise to the endothelium of vitelline vessels.- zymogenic c. a c. that secretes an enzyme; specifically a chief c. of a gastric gland or an acinar c. of the pancreas. SYN: albuminous c. (2), chief c. of stomach, peptic c..* * *Cost Effectiveness of Lipid Lowering [study]
* * *cell 'sel n1) a small compartment or bounded space2) a small usu. microscopic mass of protoplasm bounded externally by a semipermeable membrane, usu. including one or more nuclei and various nonliving products, capable alone or interacting with other cells of performing all the fundamental functions of life, and forming the smallest structural unit of living matter capable of functioning independently
* * *n.the basic unit of all living organisms, which can reproduce itself exactly (see mitosis). Each cell is bounded by a cell membrane of lipids and protein, which controls the passage of substances into and out of the cell. Cells contain cytoplasm, in which are suspended a nucleus and other structures (organelle) specialized to carry out particular activities in the cell.Complex organisms are built up of millions of cells that are specially adapted to carry out particular functions. The process of cell differentiation begins early on in the development of the embryo and cells of a particular type (e.g. blood cells, liver cells) always give rise to cells of the same type. Each cell has a particular number of chromosome in its nucleus. The sex cells (sperm and ova) always contain half the number of chromosomes of all the other cells of the body (see meiosis); at fertilization a sperm and ovum combine to form a cell with a complete set of chromosomes that will develop into the embryo.
* * *(sel) [L. cella compartment] 1. the smallest living unit capable of independent function, consisting of cytoplasm containing various subcellular compartments (organelles and cytosol) and separated from the external environment by the plasma membrane. Eukaryotic cells also include a nucleus containing the genome and nucleolus; prokaryotic cells lack a nucleus and DNA is present as a naked chromosome. Cells may exist as independent organisms or, with specialization for specific functions, be subunits of more complex organisms. See Plates 11 and 12. 2. a small, more or less enclosed space; see also cellula.
PLATE 11 THE CELL: CELL STRUCTURES AND EPITHELIAL CELL TYPES
PLATE 12 CELL ORGANELLES AND PLASMA MEMBRANE
Medical dictionary. 2011.