cell (sel) [L. cella, a chamber]
GENERALIZED HUMAN CELL AND ORGANELLES
The basic unit of life. A cell is a group of self-sustaining biochemical reactions that are isolated from the environment by a selectively permeable lipid membrane. Among the key reactions are those that maintain a stable intracellular concentration of ions; for mammalian cells, typical internal concentrations include 140 mM K+, 5-15 mM Na+, 5-15 mM Cl-, and a pH of 7.2, which can be significantly different from their concentrations outside the cell. Other key reactions move molecules and molecular complexes within the cell, sometimes changing the cell's shape. These reactions, along with many others, require energy, and the generation of energy by breaking apart preexisting hydrocarbon molecules ("food") is the job of glycolysis and other characteristic intracellular metabolic reactions. See: glycolysis
Intracellular chemical reactions are controlled by enzymes that are organized in stable molecular complexes called organelles. The polymer-based organelles include centrioles and the cytoskeleton; nucleic acid-based organelles include ribosomes; and membrane-enclosed organelles include the nucleus, endoplasmic reticula, Golgi complexes, lysosomes, peroxisomes, mitochondria, and storage and transport vesicles. See: illustrationIndividual mammalian cells are usually microscopic, typically ranging from 5 µm to 50 µm in diameter. In humans, lymphocytes are small cells (~6 µm in diameter), columnar epithelial cells (10 µm x 20 µm) are medium-size cells, and mature ova (120-150 µm) are some of the largest cells.
In mammals, all new cells arise from existing cells through cell division, and an animal's growth results largely from increases in the number of its cells, most of which differentiate into specialized cell types to form the body's various tissues. Cell division involves two major processes: karyokinesis, the division of the nucleus, and cytokinesis, the division of the remainder of the cell. When generating somatic daughter cells, karyokinesis uses a process called mitosis, which produces daughter cells with a full complement of chromosomes. When generating germ cells, karyokinesis includes a process called meiosis, which produces daughter cells with half the normal number of chromosomes. See: meiosis and mitosis for illus.
Alpha cell of the pancreas.
A monocyte or macrophage that participates in the immune response. See: antigen-presenting cell; macrophage
A cell present in the acinus of an acinous gland, e.g., of the pancreas.
adult stem cell
A precursor cell that can also give rise to identical precursor cells: daughters of a stem cell can develop into a terminally-differentiated cell type or they can remain a stem cell. Adult stem cells are found in many tissues, such as bone marrow, brain, retina, skin, intestines, liver, testis, and pancreas. Synonym: somatic stem cell See: embryonic stem cell
A macrophage along a blood vessel, together with perivascular undifferentiated cells associated with it.
An air-filled sinus cavity in a bone.
1. An enteroendocrine cell that produces glucagon and is found in the pancreatic islets. Synonym: A cell
2. An acidophil of the adenohypophysis (anterior pituitary gland).
1. In the lung, either of two types of epithelial cells lining the alveoli. Type I cells are simple thin squamous epithelial cells. Type II cells secrete pulmonary surfactant. Type II cells are smaller and more numerous than Type I cells.
2. In the mammary glands, the milk-secreting epithelial cells, which are activated during lactation.
A modified nerve cell in the retina that has dendrites but no axon. See: neuron
anterior horn cell
A somatic motor neuron that has its cell body in the ventral (anterior) horn of the gray matter of the spinal cord; its axon passes out through a ventral root and innervates skeletal muscle.
antigen-presenting cell Abbreviation: APC
A cell that breaks down antigens and displays their fragments on surface receptors next to major histocompatibility complex molecules. This presentation is necessary for some T lymphocytes that are unable to recognize soluble antigens. Macrophages are the primary antigen-presenting cells, but B cells and dendritic cells also can act as APCs. See: T cell; macrophage processing cell
The abbreviated name for an 'amine precursor uptake and decarboxylation cell'. These cells are the constituents of a diffuse neuroendocrine system and all have metabolic pathways that make and utilize serotonin (5-HT). APUD cells include chromaffin cells, enterochromaffin cells, and SIF cells as well as certain cells found in the parathyroid gland, thyroid gland, pituitary gland, hypothalamus, and placenta.
A cell in the epithelium of the stomach, intestines, and appendix that secretes serotonin.
atypical glandular cells Abbreviation: AGC
An abnormal finding on a Pap test. This classification is divided into “favor neoplasia” or “not otherwise specified (NOS).” NOS is subdivided into endocervical or endometrial origin. Atypical endocervical cells are important because of their risk for significant disease. Synonym: atypical glandular cells of undetermined significance
atypical glandular cells of undetermined significance Abbreviation: AGUS
Atypical glandular cells.
A lymphocyte that synthesizes and secretes antibodies. B lymphocytes originate and differentiate in the bone marrow and then populate the spleen, lymph nodes, and other lymphoid tissues. When exposed to an antigen, a B cell divides to form (a) plasma cells, which produce antigen-specific antibodies, and (b) a lesser number of memory B cells, which can quickly differentiate into plasma cells upon a second exposure to the original antigen. Antibody production is a key part of the humoral immune response of adaptive immunity. The humoral immune response is effective against bacteria, viruses, and other pathogens, and provides the rationale for vaccination. Synonym: B lymphocyte
See: ; T cell
2. Pancreatic beta cell.
The developing leukocyte at a stage at which the nucleus is not segmented.
1. A rounded or cuboidal epithelial stem cell found in the bottom layer of pseudostratified epithelia, such as the epidermis and the lining of the airways of the lung.
2. Either of two types of cell found in the bottom layer of the olfactory epithelium; one type is a flattened "basal cell proper", and the other is a rounded stem cell called a globose cell.
3. A rounded stem cell found in the taste buds and a progenitor of the specialized taste receptor cells.
1. Myoepithelial cell.
2. One of the nonspiny granule cells found in the cerebral cortex.
3. One of the small interneurons found in the outermost layer of the cerebellar cortex along with stellate cells.
1. Any of the insulin-secreting cells of the pancreas that constitute the bulk of the islets of Langerhans. Synonym: B cell
2. A basophil cell of the adenohypophysis (anterior pituitary gland).
Betz cell See: Betz cells
1. A precursor cell for a specific cell type.
2. An immature cell of a specific type.
Any cell normally found circulating in the blood stream. Blood cells include red cells and white cells; red cells generally remain inside blood vessels, while white cells can also more into the tissues outside the blood vessel walls. See: blood for illus.
An osteoblast, osteoclast, or osteocyte.
bone marrow cell
An epithelial cell found sparsely in the lining of the bronchial tree. The cell's surface has long stiff microvilli, and the cell has the appearance of an absorptive cell.
An erythrocyte with 10 to 30 spicules distributed over the surface of the cell, as seen in heart disease, stomach cancer, kidney disease, and dehydration. Synonym: echinocyte
A cell present in a neoplasm and differentiated from normal tissue cells because of its degree of anaplasia, irregularity of shape, nuclear size, changes in the structure of the nucleus and cytoplasm, increased number of mitoses, and ability to metastasize.
capsule cellSatellite cell.
An enlarged and vacuolated basophil cell seen in the pituitary in gonadal insufficiency or following castration.
Helper T cell.
A suppressor T cell, e.g., a cytotoxic T cell.
CD 34+ cell
A cell with the CD34 protein on its surface membrane. Some CD34 cells that are hemopoietic stem cells can be separated out from peripheral blood.
Any of the cells trapped within cementum that maintain cementum as a living calcified tissue by their metabolic activity.
A duct cell of the pancreas more or less invaginated into the lumen of an acinus.
chalice cellGoblet cell.
1. Any of the cells of the parathyroid gland that secretes the parathyroid hormone.
2. Any of the cells of the gastric glands that secretes pepsinogen.
A cell that produces, stores, and secretes catecholamines (dopamine and norepinephrine). Chromaffin cells are found in the medulla of the adrenal glands and in small clusters in the sympathetic ganglia.
A cuboidal epithelial cell found in the lining of the terminal and the respiratory bronchioles of the lungs. Clara cells are nonciliated, and they secrete surfactant, like the type II alveolar epithelial cells found deeper in the bronchial tree.
A vaginal epithelial cell, thickly coated with coccobacillary organisms. Clue cells are a hallmark of bacterial vaginosis.
An epithelial cell with height greater than its width.
columnar epithelial cell
A cell in the retina whose scleral end forms a cone that serves as a light receptor. Vision in bright light, color vision, and acute vision depend on the function of the cones. See: rod cell
A T cell that inhibits the activity of suppressor T cells. Although a contrasuppressor cell shares this functional capability with T helper cells, it is distinguished from other CD4+ cells by its other cell surface markers and the unique group of cytokines it produces.
A cell in the cortex of an organ, e.g., a neuron in the cerebral cortex.
A cell – usually epithelial – with a height about equal to its width and depth.
Cytotoxic T cell.
cytotoxic T cell
A CD8+ T lymphocyte that can destroy microorganisms directly through the release of perforin and proteolytic enzymes. These cells are particularly important in the defense against viruses, rejection of allografts, and, possibly, new malignant cells. Synonym: CD8 cell; cytotoxic cel; killer T cell
An enteroendocrine cell that produces somatostatin and is found in the pancreatic islets, stomach, and small intestine. Synonym: delta cell; somatostatin cell
A cell formed by cell division.
A cell found in the urine with inclusion bodies in its nucleus. It indicates infection with BK virus in renal transplant recipients.
Pancreatic D cell.
One type of antigen-presenting cell that helps T cells respond to foreign antigens. Dendritic cells are found in epithelial tissues and include the Langerhans' cells of the skin and the interdigitating cells in lymph nodes; they also circulate in the blood.
Downey cell See: Downey cell
A macrophage that migrates into the lumen of lung aveoli and ingests debris, particles of air pollution, and pathogens to keep the airspaces clear.
1. An embryonal carcinoma cell, which is a cultured cell line.
2. An enterochromaffin cell that secretes substance P and is found in the stomach and small intestine.
A cell that carries out the final response or function of a particular process. The main effector cells of the immune system, for example, are activated lymphocytes and phagocytes—the cells involved in destroying pathogens and removing them from the body. See: leukocyte
embryonic stem cell Abbreviation: ES cell
A cell from the inner cell mass of the blastocyst (the 3-5 day old mammalian embryo) that can give rise to all the somatic cells of the body. Embryonic stem cells can be maintained as pure stem cell cultures. See: adult stem cell
The type of epithelial cell that lines blood vessels and lymph vessels; these cells are usually squamous (flattened) and form sheets one layer thick. Endothelial cells are derived from mesenchyme cells of the embryo. A sheet of endothelial cells is called an endothelium. See: endothelium
enterochromaffin cell Abbreviation: EC cell
An enteroendocrine cell that produces serotonin and is found in the small intestine. Enterochromaffin cells are very similar to the cells, found throughout the peripheral sympathetic nervous system, that are called simply 'chromaffin cells'.
One of the scattered hormone-producing cells found in the pancreatic islets and throughout the gastrointestinal (mainly, small intestinal) mucosa.
Any of the epithelial cells that form a one-cell-thick layer lining the ventricles and the central canal of the central nervous system. The ventricular (apical) surfaces of many ependymal cells are covered with cilia or microvilli. In most places, the ependymal layer does not have a basal lamina. Specialized regions of ependymal cells include the covering of the blood vessels and loose connective tissue of the choroid plexuses; here, the ependyma is specialized to secrete cerebrospinal fluid.
Any of the cells forming the cellular sheets that cover surfaces, both inside and outside the body. Epithelial cells are closely packed and take on polyhedral shapes, from tall (columnar) through squat (cuboidal) to flat (squamous). Epithelial cells adhere strongly to one another, and one of their surfaces -- the basal surface -- sticks firmly to a thin extracellular film of fibrils called a basal lamina. A sheet of epithelial cells derived from embryonic epithelia (the ectoderm or the endoderm) is called an epithelium. See: epithelium
ethmoid air cell
The type of cell composing multicellular, as well as a number of unicellular, organisms. Unlike prokaryotic cells, eukaryotic cells have many of their intracellular functions organized within structures called organelles. Some organelles -- notably, the nucleus, which contains the DNA -- are enclosed by intracellular membranes.
An enteroendocrine cell that produces pancreatic polypeptide and is found in the pancreatic islets.
A bone marrow cell with a bright red cytoplasm, occasionally found in the marrow of patients with multiple myeloma.
An optical cell used in photometers and cell counters, through which the sample and any standards are passed for detection and measured or counted by optical or electrometric means. See: cytometry
A cell that contains vacuoles; a lipid-filled macrophage.
1. The secretory cell of the thyroid gland; it produces the thyroid hormones, T3 (triiodothyronine) and T4 (tetraiodothyronine or thyroxine).
2. Any of the flattened somatic cells that form a monolayer around each primary oocyte in the ovary. After puberty, when an oocyte matures, during a monthly cycle, its follicular cells divide, become cuboidal, and form a multilayered coating for the oocyte; at this stage, the follicular cells are called granulosa cells.
A supporting cell in the adenohypophysis (anterior pituitary gland); it produces bioactive peptides, including growth factors and cytokines.
foreign body giant cell
An enteroendocrine cell found in the stomach that produces the hormone gastrin.
1. Any neuron whose cell body is located within a ganglion.
2. A neuron of the retina of the eye whose cell body lies in the ganglion cell layer. The axons of ganglion cells form the optic nerve.
A cell whose function is to reproduce the organism. Early in development, primordial germ cells are found in the genital ridges of the embryo. Later, in the testis, the primordial germ cells are called spermatogonia, and in the ovary, they are called oogonia. When they mature, the germ cells (i.e., spermatogonia and oogonia) differentiate into haploid gametes (i.e., spermatozoa and ova). Synonym: primordial germ cell
A multinucleated phagocyte created by several individual macrophages that have merged around a large pathogen or a substance resistant to destruction, such as a splinter or surgical suture. See: granuloma
2. A large multinucleated (40-60 nuclei) tumor cell characteristic of certain bone and tendon tumors.
3. A large multinucleated cell that invades the walls of the aorta and its major branches in giant cell arteritis.
One of three types of nonneuronal cell in the central nervous system: astrocytes, oligodendrocytes, and microglial cells. SYN neuroglial cell Synonym: neuroglial cell
A macrophage present at sites of brain injury. The cells are packed with lipoid granules from phagocytosis of damaged brain cells. See: microglia
One of the two varieties of basal cell found in the olfactory epithelium. It is a rounded neuroblast or neural stem cell for the olfactory receptor cells.
A mucous cell sitting between nonsecretory cells, such as is found in the intestinal epithelium.
Golgi cell See: Golgi, Camillo
graft facilitating cell
Any of a group of CD8 positive, t-cell receptor negative cells that help donated bone marrow engraft in the recipient.
1. Any of the small neurons that pack the granular cell layer of the cerebellar cortex, immediately below the Purkinje cell layer. Granule cells receive inputs (mossy fibers) from the spinal cord and brainstem (except the inferior olive). Axons of granule cells run perpendicular to the Purkinje cell dendrites, on which they synapse.
2. Any of the neurons of the cerebral cortex that are not pyramidal cells. Cortical granule cells are categorized as spiny or nonspiny. Synonym: stellate cell
3. A small axon-less neuron found in the olfactory bulb.
One of the many cuboidal cells that surround and nurture the maturing oocyte. See: follicular cell (2)
An epithelial cell possessing stereocilia in the maculae, cristae ampullaris, and the organ of Corti. These cells are receptors for the senses of position and hearing.
heart failure cell
A red-colored (from ingested red cells) lung macrophage often found in the sputum of patients with congestive heart failure.
A line of human epithelial cells that grows well in culture. It is an immortal cancer cell that has been maintained in continuous tissue cultures for decades from a patient with carcinoma of the cervix. It is named for the first two letters of the patient's first and last names, Henrietta Lacks. HeLa cells have been used in thousands of experiments on cell growth, differentiation, and cancer, and in virology, pharmacology, and other fields.
HELMET CELLS: (Orig. mag. ×640)
A schistocyte or fragmented blood cell, seen in hemolytic anemias. See: illustration
A type of T lymphocyte whose surface is marked by CD4 receptors; it is involved in both cell-mediated and antibody-mediated immune responses. It secretes cytokines that stimulate the activity of B cells and other T cells and binds with class II histocompatibility antigens, which are processed by macrophages and other antigen-presenting cells. Synonym: helper T cell See: antigen processing
; T cell
; cell-mediated immunity
helper T cell
hematopoietic stem cell
A progenitor cell in the bone marrow that can replicate itself as well as produce precursor cells of the various blood cell lineages.
An androgen-producing cell found in the ovarian hilum. It is analogous to the male Leydig cell.
holly leaf cell
A cell found in blood smears of persons with sickle cell anemia.
A neuron of the inner nuclear layer of the retina. The axons of these cells run horizontally and connect various parts of the retina.
Hürthle cell See: Hürthle cell
hybridoma cell See: hybridoma
A cell that contains more than the normal number of chromosomes and hence stains more densely.
An enteroendocrine cell that produces the enzyme cholecystokinin-pancreozymin (pancreaticozymin) and is found in the small intestine.
A type of antigen-presenting cell found in lymph nodes and lymphoid tissue.
Any of the many cells found in connective tissue of the ovary, in the seminiferous tubules of the testes, and in the medulla and cortex of the kidney. The cells in the testes and ovaries produce hormones such as testosterone and estrogen.
intestinal absorptive cell
In the small intestine, any of the tall columnar cells topped with a brush border made of thousands of microvilli.
A cell of the islets of Langerhans of the pancreas.
The early developmental form of a leukocyte.
A modified smooth muscle cell in the wall of the afferent arteriole leading to a glomerulus of the kidney. This type of cell secretes renin when blood pressure decreases to activate the renin-angiotensin mechanism, which increases sodium retention, thus elevating the blood pressure.
An enteroendocrine cell that produces gastric inhibitory peptide (glucose-dependent insulinotropic peptide) and is found in the small intestine. This peptide stimulates the beta cells of the pancreas to secrete insulin.
Natural killer cell.
killer T cellCytotoxic T cell.
An APUD cell found in the lung.
Kupffer cell See: Kupffer cell
An enteroendocrine cell that produces glucagon-like peptide-1 and is found in the small intestine. This peptide signals the pancreas to secrete insulin after a meal.
A cell that is always mitotically active, such as the epithelial cells lining the stomach and the stem cells in the red bone marrow.
Abbreviation for lymphokine-activated killer cell. These natural killer cells, obtained from the patient's blood, have been activated in culture with interleukin-2.LAK cells; the cells can then be used to treat patients with solid malignant tumors.
A type of dendritic antigen-presenting cell that typically resides in the skin.
L.E. CELL (center): (Orig. mag. ×1000)
Historically, an abbreviation for lupus erythematosus
cell, a polymorphonuclear leukocyte that contains the phagocytized nucleus of another cell. It is characteristic but not diagnostic of lupus erythematosus.
This distinctive cell may form when the blood of patients with systemic lupus erythematosus is incubated and further processed according to a specified protocol. The plasma of some patients contains an antibody to the nucleoprotein of leukocytes. These altered nuclei, which are swollen, pink, and homogeneous, are ingested by phagocytes. These are the L.E. cells. The ingested material, when stained properly, is lavender and displaces the nucleus of the phagocyte to the inner surface of the cell membrane. The L.E. cell phenomenon can be demonstrated in most patients with systemic lupus erythematosus but is not essential for diagnosis.
Leydig cell See: Leydig's cell
A macrophage found in the sinuses of lymphatic tissue.
A cell of the corpus luteum of the ovary that contains fatty yellowish granules. Granulose lutein cells are hypertrophied follicle cells; these lutein (paralutein) cells develop from the theca interna.
An obsolete term for lymphocyte.
lymphokine-activated killer cell
1. A microfold cell, which is a cell in the gastrointestinal epithelium covering patches of lymphoid tissue. M cells transport antigens from the intestinal lumen to the underlying lymphoid tissues for recognition and processing.
2. An APUD cell that produces melanotropin and is found in the pituitary gland.
An astrocyte or an oligodendrocyte.
Bone marrow cell.
A large tissue cell resembling a basophil, which is essential for inflammatory reactions mediated by immunoglobulin E (IgE) but does not circulate in the blood. Mast cells are present throughout the body in connective tissue, but are concentrated beneath the skin and the mucous membranes of the respiratory and digestive tracts. Mast cells are covered with IgE molecules, which bind with foreign antigens and stimulate degranulation, releasing such mediators as histamine, prostaglandins, leukotrienes, and proteinases from densely packed granules within the cytoplasm. These mediators produce type I (immediate) hypersensitivity reactions (e.g., urticaria, allergic rhinitis, asthma, angioedema, and systemic anaphylaxis). See: illustration
Mastoid air cell.
mastoid air cell
Any of the variable-sized, air-filled sinuses inside the mastoid antrum. About 20% of adult skulls have no mastoid air cells.
matrix stem cell
A stem cell derived from Wharton's jelly.
A cell derived from B or T lymphocytes that can quickly recognize a foreign antigen to which the body has been previously exposed. Memory T cells stimulate T helper lymphocytes and cytotoxic T cells; memory B cells stimulate the production of antigen-specific antibodies by B plasma cells. Both types of memory cells survive for years, providing a durable adaptive immune response against foreign antigens.
One of the two basic somatic cell lineages -- the other being epithelial cells. In contrast to epithelial cells, mesenchyme cells are not polarized and are frequently motile. In the early embryo, mesenchyme cells fill many of the spaces enclosed by epithelia. Later, mesenchyme cells will secrete the space-filling extracellular matrix molecules, such as collagen and glycoproteins, that characterize connective tissue.
mesenchymal stem cell
A stem cell found in connective tissue and capable of producing cells of the connective tissue lineages, such as cartilage, bone, muscle, and fat cells.
The type of epithelial cell that lines serous (pleural, peritoneal, and pericardial) cavities, blood vessels, and lymph vessels; these cells are usually squamous (flattened) and form sheets one layer thick. Mesothelial cells are derived from mesenchyme cells of the embryo. A sheet of mesothelial cells is called a mesothelium. See: mesothelium
A small glial cell of the central nervous system and retina. Microglia have spiky branched processes and are arranged homogeneously throughout the brain and spinal cord. They are activated by disease and injury, after which they become phagocytic and sometimes resume their embryonic motility like a macrophage.
One of the two principal neurons of the olfactory bulb -- the other being the tufted cell. In a complex synaptic formation called a glomerulus, each of the mitral and tufted cells receives synaptic inputs from axons of the olfactory nerve. The axons of the mitral and tufted cells form the olfactory tract and synapse in the olfactory cortex.
An astrocyte or other glial cell with many branching processes. See: neuroglia
A cell that gives rise to similar cells through fission or budding. Synonym: parent cell
Any cell in a mucosal epithelium.
An epithelial cell that secretes mucus and IgA antibodies. Mucous cells and serous cells are the two varieties of secretory cells found in exocrine glands. Synonym: mucus cell
multinucleated giant cell
muscle cell See: muscle
Any white blood cell other than lymphocytes.
A cell present in the bone marrow of patients with multiple myeloma.
A smooth muscle cell found in some epithelia; it lies between glandular cells and the basal lamina of sweat, mammary, lacrimal, and salivary glands. Synonym: basket cell
natural killer cell Abbreviation: NK cell
A large granular lymphocyte – a defensive cell of innate immunity – that bonds to cells and lyses them by releasing cytotoxins. Natural killer cells are null cells, lymphocytes that do not have B cell or T cell surface markers, and they can be activated without previous antigen exposure. NK cells destroy cells infected with viruses and some types of tumor cells in cultures. They also secrete gamma interferon (INF?), tumor necrosis factor alpha (TNFa), and granulocyte-macrophage colony-stimulating factor (GMCSF), enhancing the effect of T lymphocytes. Synonym: killer cell
neural crest cell
Embryonic cells of the neuron-glia lineage that form along the ridges (neural folds) of the neural plate and that migrate into the developing organism to produce a variety of tissues. The migratory ability of these embryonic epithelial cells is similar to the motility of mesenchyme cells; this has led neural crest cells to be called mesectodermal cells. In the neural lineage, neural crest cells give rise to the dorsal root ganglia, the placodes that will develop into the olfactory and auditory sensory organs, the pituitary gland, the peripheral autonomic nervous system, and the neurenteric and APUD cells. In the glial lineage, neural crest cells give rise to Schwann cells and other peripheral satellite cells. In addition, neural crest cells of the cranial region give rise to certain facial connective tissue, including the bones of the nasal cavities, the roof of the mouth, and the sella turcica.
Niemann-Pick cell See: Niemann-Pick cell
Natural killer cell.
Any cell found in the bone marrow that cannot reconstitute the marrow or give rise to more differentiated blood cells.
A large lymphocyte without the cell markers of either a T cell or a B cell. Natural killer cells are examples of null cells.
Olfactory receptor cell.
olfactory receptor cell
A cell of the olfactory mucosa that has receptors for the sense of smell. Olfactory cells are continuously replaced from stem cells throughout adult life. Synonym: olfactory cell
Any of the mesenchyme precursor cells committed to the bone lineage and capable of producing osteoblasts and osteocytes. Osteoprogenitor cells are found in bone, bone marrow, and other connective tissue.
A parietal cell of the gastric glands; it produces hydrochloric acid and the intrinsic factor.
An abnormal but not malignant cell seen in some cytologic specimens obtained during Papanicolaou tests (Pap tests). It is found in women with vaginal atrophy, in some postpartum women, some women suffering from anorexia or starvation, and some who have used progesterone for contraception.
parent cellMother cell.
One of the cells supporting the hair cells of the organ of Corti. These cells form several rows of outer phalangeal cells (Deiters' cells) and a single row of inner phalangeal cells.
phantom cell See: red cell ghost
Any cell that normally contains pigment granules.
A cell derived from a B lymphocyte that has been sensitized to a specific foreign antigen and produces antibodies to that particular antigen. It may be found in the blood or in tissue fluid. Synonym: plasmacyte
An enteroendocrine endocrine cell found in the pancreatic islets that produces pancreatic polypeptide.
The immediate precursor of a lymphocytic B cell.
A cell with spiny processes that connect with similar processes of adjoining cells. These are found in the stratum spinosum of the keratinized epithelium of the epidermis.
In physical therapy, a device consisting of a container, two solid conducting elements, and an electrolyte for the production of electric current by chemical energy.
Primordial germ cell.
primordial germ cell
A germ cell before it begins its maturation into a haploid gamete. Synonym: primordial cell
progenitor cellA cell (sometimes a stem cell) that produces cells of a particular lineage, e.g., a neuroblast.
The form of cell composing many primitive unicellular organisms, such as bacteria. Prokaryotic cells do not have nuclei, which are partitioned by an intracellular membrane; instead the DNA forms one main coil in the cell cytoplasm.
Purkinje cell See: Purkinje, Johannes E. von
A leukocyte present in pus. Pus cells are often degenerated or necrotic.
A large, common neuron found in the cerebral cortex. Pyramidal cells are flask-shaped or triangular, and, in the parts of the cortex with six layers, they occupy the fifth layer. Pyramidal cell dendrites project up into the most superficial layer of the cortex, while pyramidal cell axons run in the opposite direction, i.e., downward and out of the cortex. Synonym: pyramidal neuron
radial glial cell
A structural macroglial cell that is a key component of the developing nervous system. Radial glial cells first appear in the neural tube, where their cell bodies are suspended between two thin cell processes; the apical process attaches to the inner (ventricular) surface of the neural tube, and the basal process attaches to the outer (pial) surface. Early in development, neuroblasts migrate radially along the scaffolding formed by the radial glial cell processes, and growing axons may follow the scaffolding longitudinally. Later, many radial glial cells retract their processes and differentiate into astrocytes.
A small cell that is filled with hemoglobin, has no nucleus, and is shaped like a biconcave disc. Red cells transport oxygen to tissues and carbon dioxide to the lungs. Individual red cells have a life span of 3-4 months, and new red cells are continually being produced in the bone marrow. In a healthy person, 99% of the cells circulating in the blood are red cells. Synonym: erythrocyte; red blood cell; red blood corpuscle See: erythrocyte
red blood cell Abbreviation: RBC
Renshaw cell See: Renshaw cell
2. A cell not performing its normal function (i.e., a nerve cell that is not conducting an impulse or a muscle cell that is not contracting).
1. An undifferentiated cell of the spleen, bone marrow, or lymphatic tissue that can develop into one of several types of connective tissue cells or into a macrophage.
An out-of-date term for a cell of the mononuclear phagocytic system.
Rieder cell See: Rieder cell
A cell in the retina of the eye whose scleral end is long and narrow, forming a rod-shaped sensory receptor. Rods are stimulated by light and are essential for vision in dim light. See: cone cell
A rose-shaped cluster of phagocytes surrounding lysed nuclear material or red blood cells. Rosette cells occur frequently in blood in which L.E. cells are present. Rosette cells are not diagnostic of lupus erythematosus. See: L.E. cell
Rouget cell See: Rouget cell
An enteroendocrine cell that produces secretin and is found in the small intestine.
1. A stem cell associated with skeletal muscle that may form a limited number of new muscle cells after injury.
2. One of the neuroglia cells enclosing the cell bodies of sensory neurons in spinal ganglia. Synonym: capsule cell
A phagocyte that cleans up disintegrating tissues or cells.
Schwann cell See: Schwann cell
A segmented neutrophil (i.e., one with a nucleus of two or more lobes connected by slender filaments).
selenoid cell See: red cell ghost
A cell that when stimulated gives rise to nerve impulses that are conveyed to the central nervous system.
A type II alveolar cell that secretes pulmonary surfactant; it is adjacent to a septum of the alveoli.
An epithelial cell that secretes a watery fluid containing proteins, glycoproteins, and often antibodies (IgA, IgG, and IgM). Serous cells and mucous cells are the two varieties of secretory cells found in exocrine glands.
Sertoli cell See: Sertoli cell
SICKLED CELLS IN SICKLE CELL DISEASE
A vacuolated cell with the nucleus off center. Mucus-secreting adenocarcinomas usually contain these cells.
skeletal muscle cell See: muscle
smooth muscle cell See: muscle
Any cell that is not a germ cell.
somatic stem cell
Adult stem cell.
spiculed red cell
Crenated red blood cells with surface projections. In most instances, this is a normal variation in red cell equilibrium and is reversible. See: acanthocyte
A flat epithelial cell. Synonym: squamous epithelial cell
squamous epithelial cell
1. Granule cell of the cerebral cortex.
2. One of the small interneurons found in the outer layer of the cerebellar cortex along with basket cells.
stellate reticuloendothelial cell
A Kupffer cell, one of the macrophages that line the sinusoids of the liver.
An embryonic stem cell or an adult stem cell.
Sternberg-Reed cell See: Reed-Sternberg cell
A red blood cell that contains small basophilic-staining dots. It is seen in lead poisoning, malaria, severe anemia, and leukemia.
striated muscle See: muscle
suppressor T cell
A subpopulation of regulatory T lymphocytes that develop in the thymus gland, that slows or stops a specific immune response.
A supporting cell, as in the acoustic macula, organ of Corti, olfactory epithelium, taste buds, or testes.
One of the large epithelial cells that occur in groups in the hilus of the ovary. They are thought to be chromaffin cells.
A chromaffin cell of ectodermal origin present in the fetal adrenal gland. Sympathetic and medullary cells originate from these cells.
syncytial giant cell
A lymphocyte that responds to specific antigens, with the assistance of antigen-presenting cells (APCs). T cells arise in the bone marrow and migrate to the thymus gland, where they mature; then they circulate between blood and lymph, serving as one of the primary cells of the adaptive immune response. Immature T cells are called thymocytes. Mature T cells are antigen specific. Their surface receptors (T cell receptors, abbrev. TCRs) respond only to a single antigen. T cells are further categorized using another family of surface protein markers called clusters of differentiation (CDs). All T cells have a CD3 marker. Additional markers differentiate the subclasses of T cells. CD4 T helper cells serve primarily as regulators, secreting cytokines that stimulate the activities of other white blood cells. CD8 T cells (cytotoxic T cells) directly lyse (kill) organisms, an important defense against viruses; most CD8 T cells also produce gamma interferon (INF?), one of the strongest stimulators of macrophage activity. Synonym: T lymphocyte
See: immune response
; immunological surveillance
; T-cell receptor
A T cell can only recognize the "foreignness" of antigens after they have been modified by macrophages and other antigen-presenting cells (APCs). After this, T cells dominate the adaptive immune response by mobilizing B cells and other T cells of the cell-mediated immune pathways. T cells are responsible for type IV hypersensitivity reactions, such as graft rejection, and for tumor cell recognition and destruction.
; cell-mediated immunity
TARGET CELLS: In hemoglobin C disease (×600)
An erythrocyte with a dark rounded central area surrounded by a lightly stained clear ring, which in turn is surrounded by a dense ring of peripheral cytoplasm. It is present in certain blood disorders, such as thalassemia, and in patients who have no spleen. See: hemoglobin C disease
for illus Synonym: codocyte
2. . The cell at which a signal (e.g., hormone or nerve impulse) is aimed.illustration
A phagocyte that has ingested the unaltered nuclei of cells. These nuclei can be observed unchanged within the phagocytes.
Any of the neuroepithelial cells within a taste bud that are receptors for the sense of taste. Each possesses on the free surface a short gustatory hair that projects through the inner taste pore. Synonym: taste receptor cell
taste receptor celltaste cell.
An abnormally shaped blood cell, sometimes found on blood smears of patients with bone marrow fibrosis, iron deficiency, or thalassemias. Synonym: dacrocyte
Any of the fibroblasts of white fibrous connective tissue of tendons arranged in parallel rows.
terminally differentiated cell
A cell sufficiently committed to a particular function that it can no longer divide, e.g. a red cell.
thymic epithelial cell
The epithelial cells that form the internal scaffolding of the thymus. These cells vary in shape and size but generally align in sheets and cords, partitioning the thymus into islands of close-packed lymphocytes in the organ's cortex. Thymic epithelial cells are not simply structural and they interact actively with adjacent lymphocytes.
Any cell characteristic of the thymus, including thymic epithelial cells and thymocytes (thymic lymphocytes).
Any cell characteristic of the thyroid gland, but usually referring to a thyroid follicular cell.
An undifferentiated embryonic cell that has the potential to develop into any type of cell.
Touton giant cell See: Touton cell
The stretchable epithelial cells that compose the transitional epithelium (uroepithelium), which lines most of the urinary tract. Transitional cells are strongly interconnected. They are cuboidal when not under pressure, and they become flattened and squamous when stretched. Transitional epithelia are 4-6 cells thick, and the top transitional cells -- those on the lumenal surface -- fuse to become larger and polyploid.
One of the epithelial cells forming the surface of the spherical blastocyst stage embryo. Trophoblast cells are destined to give rise to many of the extraembryonic tissues.
tufted See: mitral cell
Türk irritation cell See: Türk irritation cell
Tzanck cell See: Tzanck cell
A cell resembling an embryonic cell in that it does not have the specific morphologic or functional characteristics of any particular adult cell type.
A cell with a single cell process.
A lineage of cells used in cell cultures and isolated from kidney epithelial cells of the African green monkey (Cercopithecus aethiops).
A rod cell or cone cell of the retina.
A rarely used term for a cell (such as a macrophage) that moves like an ameba.
white blood cell Abbreviation: WBC
1. the basic structural unit of living organisms.
2. a small more or less enclosed space.
All living cells arise from other cells, either by division of one cell to make two, as in mitosis and meiosis, or by fusion of two cells to make one, as in the union of the sperm and ovum to make the zygote in sexual reproduction.
All cells are bounded by a structure called the cell membrane or plasma membrane, which is a lipid bilayer composed of two layers of phospholipids. Each layer is one molecule thick with the charged, hydrophilic end of the lipid molecules on the surface of the membrane and the uncharged hydrophobic fatty acid tails in the interior of the membrane.
Cells are divided into two classes, eukaryotic cells and prokaryotic cells:
Eukaryotic cells have a true nucleus, which contains the genetic material, composed of the chromosomes
, each of which is a long linear deoxyribonucleic acid
(DNA) molecule associated with protein. The nucleus is bounded by a nuclear membrane, which is composed of two lipid bilayer membranes.
Prokaryotic cells, the bacteria, have no nucleus, and their genetic material, consisting of a single circular naked DNA molecule, is not separated from the rest of the cell by a nuclear membrane.
Eukaryotic cells are larger and more complex than prokaryotic cells. They also have membrane-bounded structures, such as mitochondria, chloroplasts, Golgi apparatus, endoplasmic reticulum and lysosomes, that prokaryotic cells lack.
The contents of a cell are referred to collectively as the protoplasm. In eukaryotic cells the contents of the nucleus are referred to as nucleoplasm and the rest of the protoplasm as the cytoplasm.
The lipid bilayer of eukaryotic cells is impermeable to many substances, such as ions, sugars and amino acids; however, membrane proteins selectively move specific substances through the cell membrane by active or passive transport. Water, gases such as oxygen and carbon dioxide, and nonpolar compounds pass through the cell membrane by diffusion. Materials can also be engulfed and taken into the cell enclosed in a portion of the cell membrane. This is called phagocytosis when solids are ingested and pinocytosis when liquids are ingested. The reverse process is called exocytosis. All of these processes permit the cell to maintain an internal environment different from its exterior. See also body fluids.
The cells of the body differentiate during development into many specialized types with specific tasks to perform. Cells are organized into tissues and tissues into organs. Embedded in the cell membrane are a wide range of molecules that vary with the cell type and are typically composed of proteins or glycoproteins that have a cytoplasmic transmembrane and external domains. These molecules serve as cell receptors and are involved in signal transduction for a wide range of ligands, including hormones, cytokines and incidentally serve as receptors for viruses and drugs.
See also betz cells
, gaucher's cells
, golgi's cells
, hela cells
, hürthle cell
, kupffer's cells
, merkel cell
Structure of the cell as seen by light microscopy. By permission from Guyton R, Hall JE, Textbook of Medical Physiology, Saunders, 2000
macrophages involved in the processing and presentation of antigens making them immunogenic.
acinar cell, acinous cell
any of the cells lining an acinus, especially applied to the zymogen-secreting cells of the pancreatic acini.
one that adheres to the glass or plastic container in cell cultures, to form the monolayer. See also cell culture
1. cells in the islets of Langerhans that secrete glucagon.
2. acidophilic cells of the anterior pituitary.
enterochromaffin cells containing cytoplasmic granules capable of reducing silver compounds, located throughout the gastrointestinal tract, chiefly in the basilar portions of the gastric glands and the crypts of Lieberkühn. They secrete serotonin.
an immature neutrophil in which the nucleus is not lobulated but is in the form of a continuous band, horseshoe shaped, twisted or coiled. Called also band-form granulocyte and stab cell.
an early keratinocyte, present in the basal layer of the epidermis.
cells in the cerebellar cortex whose axons carry basket-like groups of fibrils which enclose the cell body of each Purkinje cell.
1. basophilic cells in the pancreas that secrete insulin and make up most of the bulk of the islets of Langerhans; they contain granules that are soluble in alcohol.
2. basophilic cells of the anterior pituitary.
one of the formed elements of the blood. See also blood
the nucleus of the cell and the adjacent cytoplasm in cells which have processes, e g. neurons which consist of a cell body, an axon and dendrites.
a nucleated cell in the lacunae of bone. Called also osteocyte.
cells whose cytoplasm shows fine brown granules when stained with potassium bichromate, occurring in the adrenal medulla and in scattered groups in various organs and throughout the body.
any of the cells derived from the fertilized ovum by mitosis; a blastomere.
a cell formed by division of a mother cell.
fluid loss from cells due to elevation of the osmotic pressure of blood and tissue fluid; a potent stimulus to thirst.
macrophage-like cells with long, filamentous processes located in the cortex of lymph nodes and the skin. Important in antigen trapping, processing and presentation. See also langerhans' cell
the process whereby cells become specialized usually with concurrent loss of reproductive capacity.
embryonic stem cell
a stem cell of fetal origin. See stem cell (below).
enlarged macrophages with enlarged lysosomes and much endoplasmic reticulum. May fuse to form multinucleated giant cell (below).
one of the groups of acidophilic cells in the adenohypophysis. Contains granules that stain with azocarmine dye.
a cell with a vacuolated appearance due to the presence of complex lipoids; seen in xanthoma.
a large nerve cell, especially one of those of the spinal ganglia.
a very large, multinucleate cell; applied to megakaryocytes of bone marrow, to giant cells formed by coalescence and fusion of macrophages occurring in infectious granulomas and about foreign bodies, and to certain cancer cells.
a unicellular mucous gland found in the epithelium of various mucous membranes, especially that of the respiratory passages and intestines.
one containing granules, such as a keratinocyte in the stratum granulosum of the epidermis, when it contains a dense collection of darkly staining granules.
heart failure c's, heart lesion c's
iron-containing, rust-colored macrophages found in the pulmonary alveoli in congestive heart failure.
a subset of T lymphocytes which cooperate with B and other T lymphocytes for the synthesis of antibodies to many antigens; they play an integral role in immunoregulation.
a mononucleate cell produced from a binucleate heterokaryon after the latter undergoes mitosis. Such cells are initially unstable, tending to lose randomly some of the double complement of chromosomes. Used for mapping genes to particular chromosomes. See also heterokaryon
immunologically competent cell interstitial c's
the cells of the connective tissue of the ovary or of the testis (Leydig's cells) which furnish the internal secretion of those structures, i.e. testosterone.
cells composing the islets of Langerhans in the pancreas. See alpha cells, beta cells (above).
specialized cells, containing secretory granules, located in the tunica media of the afferent glomerular arterioles. They cause aldosterone production by secreting the enzyme renin and play a role in the regulation of blood pressure and fluid balance.
K c's, killer c's
T lymphocytes or null lymphocytes that have cytotoxic activity against target cells coated with specific IgG antibody.
accumulation of cells between the arterioles at the glomerular hilus. Called also granular cell.
precursor of the malignant interdigitating reticular cell in Hodgkin-like lymphoma in humans.
a mature neutrophilic polymorphonuclear leukocyte characteristic of lupus erythematosus. See also lupus erythematosus
interstitial cells of the testis, which secrete testosterone.
the plump, pale-staining, polyhedral cells of the corpus luteum.
lymphocytes and plasma cells.
a connective tissue cell that has basophilic, metachromatic cytoplasmic granules that contain histamine, heparin, hyaluronic acid, slow-reacting substance of anaphylaxis (SRS-A), and, in some species, serotonin. Have Fc receptors specific for IgE in the cell membrane.
cell-mediated immune reaction cell migration
movement of cells from their place of origin to other tissues; one of the fundamental processes of development.
. See also neuroglia cells (below).
a cell that divides to form new, or daughter, cells.
a plasma cell with large, clear cytoplasmic pockets.
natural killer c's, NK c's
cells capable of mediating cytotoxic reactions without themselves being specifically sensitized against the target.
any cell of the nervous system; a neuron
neuroglia c's, neuroglial c's null c's
lymphocyte-like cells that lack specific antigen receptors and other surface markers characteristic of B and T lymphocytes; they include K and NK cells; their numbers are elevated in active systemic lupus erythematosus and other disease states.
a set of specialized cells of the mucous membrane of the nose; the receptors for smell.
round, oval or polyhedral cells with foamy, lipid-containing cytoplasm found in the bone marrow and spleen in Niemann-Pick disease.
a spherical or ellipsoidal cell with a single, eccentrically placed nucleus containing dense masses of chromatin in a wheel-spoke arrangement, an area of perinuclear clearing which contains the Golgi apparatus, and generally abundant cytoplasm. Plasma cells are produced by cell division of B lymphocytes following antigen stimulation and are involved in the synthesis and release of antibody. Called also plasmacyte and plasmocyte.
a dividing keratinocyte of the prickle-cell layer of the epidermis, with delicate radiating process connecting with other similar cells.
large branching cells of the middle layer of the cerebellar cortex.
red cell, red blood cell
giant histiocytic cells, typically multinucleate, which are the common histological characteristic of Hodgkin's disease in humans.
the cells forming the reticular fibers of connective tissue; those forming the framework of lymph nodes, bone marrow and spleen. They are weakly phagocytic, stromal in origin and are distinct from the monocyte-macrophage system.
any of the large nucleated cells whose cell membrane spirally enwraps the axons of myelinated peripheral neurons supplying the myelin sheath between two nodes of Ranvier.
elongated cells in the tubules of the testes to which the spermatids become attached; they provide support, protection and, apparently, nutrition until the spermatids are transformed into mature spermatozoa.
a crescentic or sickle-shaped erythrocyte seen in some humans and deer. The abnormal shape caused by the presence of varying proportions of hemoglobin S.
a cell in which the nucleus has been pressed to one side by an accumulation of intracytoplasmic mucin.
the cells of the body other than the germ cells.
conversion of a simple cell type into a specialized cell type capable of a special function, e.g. a secretory cell; a major part of the growth of an embryo and the differentiation of basic mesenchymal tissue into specialized organs.
spindle shaped cells of the dermis or subcutis; principal component of spindle cell tumors.
spiculed mature erythrocyte.
flat, scalelike epithelial cells.
see band cell (above).
any star-shaped cell, as a Kupffer cell or astrocyte, having many filaments extending in all directions.
1. any precursor cell.
2. a primitive hematopoietic cell that is capable of self-replicating or differentiating into precursor cells of erythrocytes or any of the leukocytes.
an erythrocyte containing granules that take a basic or bluish stain with Wright's stain.
a not well defined subset of T lymphocytes that are reported to inhibit antibody and cell-mediated immune responses. They may play a role in immunoregulation, and are believed to be abnormal in various autoimmune and other immunological disease states. See also T lymphocytes.
1. an abnormally thin erythrocyte showing, when stained, a dark center and a peripheral ring of hemoglobin, separated by a pale, unstained zone containing less hemoglobin; seen in various anemias and other disorders. Called also codocyte.
2. any cell selectively affected by a particular agent, such as a hormone or drug.
3. cell containing nonself antigens in its cell membranes that is a target for nonimmune and immune cytolysis, e.g. virus-infected or tumor cell.
cells in the taste buds associated with the nerves of taste.
see glandular therapy.
an embryonic cell that is capable of developing into any type of body cell.
a lymphocyte with increased basophilia.
the neuroepithelial elements of the retina.
white cell, white blood cell