[L. cella, a chamber]
In the biological sciences, the basic unit of life. It 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 to 15 mM Na+, 5 to 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 shape of the cell. These reactions require energy; energy is generated by breaking apart hydrocarbon molecules by glycolysis and other characteristic intracellular metabolic reactions.
SEE: glycolysis; SEE: metabolism; SEE: mitochondrion

Intracellular chemical reactions are controlled by enzymes that are organized in organelles (stable molecular complexes). 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.

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COMMON COMPONENTS AND ORGANELLES OF HUMAN CELLS Individual mammalian cells are usually microscopic, typically ranging from 5 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 to 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 SEE: mitosis for illus

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A cell

SEE: Alpha cell.

accessory cell

A monocyte or macrophage that participates in the immune response.
SEE: antigen-presenting cell; SEE: macrophage

acidophilic cell

SEE: acidophil

acinar cell

A cell present in the acinus of an acinous gland, e.g., of the pancreas.

adipose cell

SEE: Adipocyte.

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.
SYN: SEE: somatic stem cell
SEE: embryonic stem cell

adventitial cell

A macrophage along a blood vessel, together with its undifferentiated perivascular cells.

air cell

An air-filled sinus cavity in a bone.

alpha cell

1. An enteroendocrine cell that produces glucagon and is found in the pancreatic islets.
SYN: SEE: A cell
2. An acidophil of the adenohypophysis.
SEE: acidophil (2)

alveolar cell

1. Either of two types of epithelial cells lining the alveoli of the lung. Type I cells are simple, thin squamous epithelial cells. Type II cells, which are smaller and more numerous than Type I cells, secrete pulmonary surfactant.
2. In the mammary glands, the milk-secreting epithelial cells, which are activated during lactation.

amacrine cell

A modified nerve cell in the retina that has dendrites but no axon.
SEE: neuron

ameloblast cell

SEE: ameloblast

amine precursor uptake and decarboxylation cell

ABBR: APUD cell Any of the constituent cells of a diffuse neuroendocrine system, having metabolic pathways that make and utilize serotonin (5-HT). APUD cells include chromaffin cells, enterochromaffin cells, and certain cells found in the parathyroid gland, thyroid gland, pituitary gland, hypothalamus, and placenta.

amphophilic cell

A cell that stains with either acid (eosin) or basic (hematoxylin) stains.
SYN: SEE: amphocyte; SEE: amphophil

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.

antibody-secreting cell

A B lymphocyte that differentiates after stimulation by an antigen and a presenting cell to produce and release large amounts of immunoglobulin.

antigen-presenting cell

ABBR: 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 APCs, but B cells and dendritic cells also can act as APCs.
SEE: T cell

argentaffin cell

A cell in the epithelium of the stomach, intestines, and appendix that secretes serotonin.

astroglial cell

SEE: Astrocyte.

atypical glandular cell

ABBR: AGCs A cell that is an abnormal finding on a Pap test. These cells are divided into “favor neoplasia” or “not otherwise specified” (NOS). NOS is further subdivided into endocervical or endometrial origin. Atypical endocervical cells are important because of their risk for significant disease.
SYN: SEE: atypical glandular cell of undetermined significance

atypical glandular cell of undetermined significance

ABBR: AGUS SEE: Atypical glandular cell.

B cell

A lymphocyte that synthesizes and secretes antibodies. B cells 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 1) plasma cells, which produce antigen-specific antibodies, and 2) 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.
SYN: SEE: B lymphocyte
SEE: T cell

band cell

The developing leukocyte at a stage at which the nucleus is not segmented.

basal cell

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.
SEE: basal cell proper; SEE: globose cell
3. A rounded stem cell found in the taste buds and a progenitor of the specialized taste receptor cells.

basal cell proper

A flattened cell found in the bottom layer of the olfactory epithelium.
SEE: basal cell (2)

basket cell

1. A smooth muscle cell found in some epithelia. It lies between glandular cells and the basal lamina of sweat, mammary, lacrimal, and salivary glands.
SYN: SEE: myoepithelial cell
2. Any of the granule cells found in the cerebral cortex.
3. Any of the small interneurons found in the outermost layer of the cerebellar cortex together with stellate cells.
SEE: stellate cell

basophilic cell

SEE: basophil

beta cell

1. Any of the insulin-secreting cells of the pancreas that constitute the bulk of the islets of Langerhans.
2. A basophil of the adenohypophysis.

Betz cell

SEE: Betz cells

bipolar cell

SEE: bipolar neuron

blast cell

1. A precursor cell for a specific cell type.
2. An immature cell of a specific type.

blood cell

Any cell normally found circulating in the bloodstream. Blood cells include red cells and white cells. Red cells generally remain inside blood vessels; white cells can also move into the tissues outside the blood vessel walls.
SEE: blood for illus

bone cell

An osteoblast, osteoclast, or osteocyte.
SEE: osteoblast; SEE: osteoclast (2); SEE: osteocyte

bone marrow cell

SEE: Myeloid cell.

brush cell

An epithelial cell found sparsely in the lining of the bronchial tree. The surface of the cell has long stiff microvilli.

burr cell

SEE: Echinocyte.

cancer cell

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 cell

SEE: Satellite cell (2).

cartilage cell

SEE: Chondrocyte.

castration cell

An enlarged and vacuolated basophil seen in the pituitary in gonadal insufficiency or following castration.
SEE: basophil

CD3 cell

SEE: helper cell; SEE: T cell

CD4 cell

SEE: helper cell; SEE: T cell

CD8 cell

SEE: cytotoxic T cell; SEE: suppressor 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.

cementoblast cell

SEE: cementoblast

cementocyte cell

Any of the cells trapped within cementum whose metabolic activity maintains the cementum as living calcified tissue.
SEE: cementum

centroacinar cell

A duct cell of the pancreas invaginated into the lumen of an acinus.

chemoreceptor cell

SEE: chemoceptor

chief cell

1. Any of the cells of the parathyroid gland that secretes parathyroid hormone.
2. Any of the cells of the gastric glands that secretes pepsinogen.

chromaffin cell

A cell that produces, stores, and secretes catecholamines. The cells are found in the medulla of the adrenal glands and in small clusters in the sympathetic ganglia.

chromophobe cell

SEE: chromophobe

circulating tumor cell

SEE: Micrometastasis.

Clara cell

SEE: Clara cell

cleavage cell

SEE: Blastomere.

clue cell

A vaginal epithelial cell, thickly coated with coccobacillary organisms. The cells are a hallmark of bacterial vaginosis.

columnar cell

An epithelial cell with height greater than its width.
SYN: SEE: columnar epithelial cell

columnar epithelial cell

SEE: Columnar cell.

cone 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

contrasuppressor cell

A T cell that inhibits the activity of suppressor T cells. A contrasuppressor cell shares this function with T helper cells, but it is distinguished from other CD4+ cells by its other cell surface markers and its unique group of cytokines.
SEE: helper cell; SEE: T cell

cortical cell

A cell in the cortex of an organ, e.g., a neuron in the cerebral cortex.

cuboid cell

A cell, usually epithelial, with a height approx. equal to its width and depth.

cytotoxic cell

SEE: 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.
SYN: SEE: cytotoxic cell; SEE: killer T cell

D cell

An enteroendocrine cell that produces somatostatin and is found in the pancreatic islets, stomach, and small intestine.
SYN: SEE: delta cell; SEE: somatostatin cell

daughter cell

A cell formed by cell division.

decoy cell

A cell found in the urine with inclusion bodies in its nucleus. It indicates infection in renal transplant recipients.

delta cell

SEE: D cell.

dendritic cell

An antigen-presenting cell that helps T cells respond to foreign antigens. Dendritic cells circulate in the blood and are also found in epithelial tissues, the Langerhans cells of the skin, and the interdigitating cells in lymph nodes.

Downey cell

SEE: Downey cell

dust 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.

EC cell

1. A cultured cell line of an embryonal carcinoma cell.
2. An enterochromaffin cell that secretes substance P and is found in the stomach and small intestine.

effector cell

A cell that carries out the final response or function of a particular process. The main effector cells of the immune system are activated lymphocytes and phagocytes.
SEE: leukocyte

effector B cell

SEE: Plasma cell

embryonic stem cell

ABBR: ES cell A cell from the inner cell mass of the blastocyst 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

endothelial cell

Any of the epithelial cells that line blood vessels and lymph vessels. These cells are derived from mesenchyme cells of the embryo, are usually squamous, and form sheets one layer thick.
SEE: endothelium

enterochromaffin cell

ABBR: EC cell An enteroendocrine cell that is found in the small intestine and produces serotonin. Enterochromaffin cells are similar to chromaffin cells.

enteroendocrine cell

Any of the scattered hormone-producing cells found in the pancreatic islets and throughout the gastrointestinal mucosa.

ependymal cell

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. Specialized regions of ependymal cells include the covering of the blood vessels and loose connective tissue of the choroid plexus.
SYN: SEE: ependymoblast; SEE: ependymocyte
SEE: choroid plexus

epithelial cell

Any of the cells forming the cellular sheets that cover surfaces 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) sticks firmly to the basal lamina.
SEE: epithelium

ethmoid cell

SEE: Ethmoid sinus.

ethmoid air cell

SEE: Ethmoid sinus.

eukaryotic cell

The type of cell composing multicellular and a number of unicellular organisms. Unlike prokaryotic cells, eukaryotic cells have many of their intracellular functions organized within organelles.
SEE: organelle

F cell

An enteroendocrine cell that produces pancreatic polypeptide and is found in the pancreatic islets.

fat cell

SEE: Adipocyte.

flame cell

A bone marrow cell with a bright red cytoplasm, occasionally found in the marrow of patients with multiple myeloma.

flow cell

An optical cell used in photometers and cell counters. Samples and standards are passed for detection and measured or counted by optical or electrometric means.
SEE: cytometry

flower cell

Abnormal lymphocytes with petal-shaped nuclei.

foam cell

A lipid-filled macrophage that contains vacuoles.

follicle cell

SEE: Follicular cell.

follicular cell

1. The secretory cell of the thyroid gland.
SEE: thyroid hormone
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.
SYN: SEE: follicle cell

folliculostellate cell

A supporting cell in the adenohypophysis. It produces bioactive peptides, including growth factors and cytokines.

foreign body giant cell

SEE: Giant cell.

G cell

An enteroendocrine cell that is found in the stomach and produces gastrin.

ganglion cell

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.

germ cell

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.

giant cell

1. 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; SEE: tuberculosis
2. A large multinucleated (40 to 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.
SYN: SEE: foreign body giant cell; SEE: multinucleated giant cell; SEE: syncytial giant cell

gitter cell

A macrophage present at sites of brain injury. The cells are packed with lipoid granules from phagocytosis of damaged brain cells.
SEE: microglia

glial cell

glia cell One of three types of cells in the central nervous system that are not neuronal.
SYN: SEE: neuroglial cell; SEE: neurogliacyte
SEE: astrocyte; SEE: microglial cell; SEE: oligodendrocyte

globose cell

One of two types of basal cell found in the olfactory epithelium. It is a rounded neuroblast or neural stem cell for the olfactory receptor cells.

goblet cell

A mucous cell located between nonsecretory cells, as is found in the intestinal epithelium.

Golgi cell

SEE: Golgi, Camillo

graft facilitating cell

Any of a group of CD8+ T-cell receptor-negative cells that help donated bone marrow engraft in the recipient.

granule cell

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 from the spinal cord and brainstem. 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.
3. A small neuron that has no axons, found in the olfactory bulb.

granulosa cell

One of the many cuboidal cells that surround and nurture the maturing oocyte.
SEE: follicular cell

gustatory cell

SEE: Taste cell.

hair cell

An epithelial cell possessing stereocilia in the maculae, cristae ampullaris, and organ of Corti. These cells are receptors for the senses of position and hearing. Hair cells do not regenerate after they are damaged or lost.

heart failure cell

A red lung macrophage often found in the sputum of patients with congestive heart failure. The red color is due to ingested red cells.

HeLa cell

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 cell

A schistocyte or fragmented blood cell, seen in hemolytic anemias.

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HELMET CELLS (Orig. mag. ×640)

helper cell

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.
SYN: SEE: helper T cell
SEE: antigen processing; SEE: T cell; SEE: cell-mediated immunity

helper T cell

SEE: Helper cell

hematopoietic stem cell

A progenitor cell in the bone marrow that can replicate itself and produce precursor cells of the various blood cell lineages.

hilus cell

An androgen-producing cell found in the ovarian hilum and analogous to a Leydig cell.
SEE: Leydig cell

holly leaf cell

A cell found in blood smears of people with sickle cell anemia.

horizontal cell

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

hyperchromatic cell

A cell that contains more than the normal number of chromosomes and hence stains more densely.

I cell

An enteroendocrine cell that is found in the small intestine and produces cholecystokinin.

IgE-effector cell

Any of the white blood cells, including basophils and eosinophils, released during allergic reactions.

interdigitating cell

A type of antigen-presenting cell found in lymph nodes and lymphoid tissue.

interstitial cell

Any of the numerous 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.

interstitial cell of Cajal

Any of the nerve cells in the gastrointestinal tract that form pacemaking networks that allow normal peristalsis to occur. Diseases affecting the number or the functioning of these cells cause gastrointestinal motility disorders.

intestinal absorptive cell

In the small intestine, any of the tall columnar cells topped with a brush border made of microvilli.

islet cell

A cell of the islets of Langerhans of the pancreas.

juvenile cell

The early developmental form of a leukocyte.

juxtaglomerular cell

A modified smooth muscle cell in the wall of the afferent arteriole leading to a glomerulus of the kidney. This cell secretes renin when blood pressure decreases to activate the renin-angiotensin mechanism, which increases sodium retention, thus elevating the blood pressure.

K cell

An enteroendocrine cell that is found in the small intestine and produces glucose-dependent insulinotropic peptide.

killer cell

SEE: Natural killer cell

killer T cell

SEE: Cytotoxic T cell.

Kulchitsky cell

An APUD cell found in the lung.

Kupffer cell

SEE: Kupffer cell

L cell

An enteroendocrine cell that is found in the small intestine and produces glucagon-like peptide-1.

labile cell

A cell that is always mitotically active, such as the epithelial cells lining the stomach and the stem cells in the red bone marrow.

lactotroph cell

SEE: lactotroph

Langerhans cell

SEE: Langerhans cell under SEE: Langerhans, Paul

LE cell

An abbreviation for lupus erythematosus (LE) cell, a polymorphonuclear leukocyte that contains the phagocytized nucleus of another cell. This cell may form when the blood of patients with systemic lupus erythematosus (SLE) is incubated and further processed according to 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, which are the LE 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 LE cell phenomenon can be demonstrated in most patients with SLE but is not essential for diagnosis.

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LE CELL (center) (Orig. mag. ×1000)

Leydig cell

SEE: Leydig cell

littoral cell

A macrophage found in the sinuses of lymphatic tissue.

liver cell

Any of the cells that make up 70% to 85% of the liver's cytoplasmic mass. These cells are involved in synthesis and storage of protein; the transformation of carbohydrates; the synthesis of cholesterol, bile salts and phospholipids; and the detoxification, modification, and excretion of exogenous and endogenous substances. They also initiate the formation and secretion of bile.

lutein cell

A cell of the corpus luteum of the ovary that contains fatty yellowish granules. Granulose lutein cells are hypertrophied follicle cells that develop from the theca interna.

lymphoid cell

SEE: Lymphocyte.

lymphokine-activated killer cell

ABBR: LAK cell Any of the natural killer cells obtained from the patient's blood and activated in culture with interleukin-2 LAK cells. The cells can then be used to treat patients with solid malignant tumors.

macroglial cell

An astrocyte or an oligodendrocyte.
SEE: astrocyte; SEE: oligodendrocyte

marrow cell

SEE: Myeloid cell.

mast cell

A large tissue cell resembling a basophil, essential for allergic and inflammatory reactions mediated by immunoglobulin E (IgE). Mast cells do not circulate in the blood although the substances they release may have systemic effects. 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.

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mastoid cell

SEE: Mastoid air cell

mastoid air cell

Any of the variable-sized, air-filled sinuses inside the mastoid process. About 20% of adult skulls have no mastoid air cells.
SYN: SEE: mastoid cell

matrix stem cell

A stem cell derived from Wharton jelly.

memory cell

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.

mesectodermal cell

SEE: Neural crest cell

mesenchyme cell

One of the two basic somatic cell lineages. The second somatic cell lineage is the epithelial. 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.

mesothelial cell

The type of epithelial cell that lines serous (pleural, peritoneal, and pericardial) cavities, blood vessels, and lymph vessels. These cells are usually squamous and form sheets (mesothelia) one layer thick. They are derived from mesenchyme cells of the embryo.
SEE: mesothelium

microfold cell

ABBR: M cell
1. 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.

microglial cell

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.

mitral cell

One of the two principal neurons of the olfactory bulb. The other principal neuron of the olfactory bulb is the tufted cell. In a glomerulus, the mitral and tufted cells receive 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.

mossy cell

An astrocyte or other glial cell with many branching processes.
SEE: glial cell; SEE: neuroglia

mother cell

A cell that gives rise to similar cells through fission or budding.
SYN: SEE: parent cell

mucosal cell

Any cell in a mucosal epithelium.

mucous cell

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.

multinucleated giant cell

SEE: Giant cell

multipolar cell

SEE: Multipolar neuron.

multi-potential progenitor cell

SEE: Stem cell.

muscle cell

SEE: muscle

myeloid cell

Any white blood cell other than lymphocytes.
SYN: SEE: bone marrow cell

myeloma cell

A cell present in the bone marrow of patients with multiple myeloma.

myoepithelial cell

SEE: Basket cell (1).

natural killer cell

ABBR: NK cell A large granular lymphocyte that bonds to cells and lyses them by releasing cytotoxins. NK cells are null cells and cannot 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, tumor necrosis factor alpha, and granulocyte-macrophage colony-stimulating factor, which enhance the effect of T lymphocytes.
SYN: SEE: killer cell

nerve cell

SEE: Neuron.

neural crest cell

Any of the embryonic cells of the neuron-glia lineage that form along the neural folds and 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 and 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.
SYN: SEE: mesectodermal cell

neuroglial cell

SEE: Glial cell.

Niemann-Pick cell

SEE: Niemann-Pick cell

nonstem cell

Any cell found in the bone marrow that cannot reconstitute the marrow or give rise to more differentiated blood cells.

null cell

1. A large lymphocyte without the cell markers of either a T cell or a B cell. Natural killer cells are examples of null cells.
2. A cell within a pituitary adenoma that neither produces nor secretes hormones.

nurse cell

A cell that binds to an oocyte and stimulates its development by supplying it with messenger RNA, ribosomes, and proteins.

odontoblast cell

SEE: odontoblast

oligodendroglial cell

SEE: oligodendrocyte.

olfactory cell

SEE: 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.
SYN: SEE: olfactory cell

osteoprogenitor cell

Any of the mesenchyme precursor cells capable of producing osteoblasts and osteocytes. Osteoprogenitor cells are found in bone, bone marrow, and other connective tissue.

oxyntic cell

SEE: Parietal cell

parabasal cell

Small, ovoid, or round epithelial cells seen on cytological examination of vaginal smears. They have relatively large nuclei relative to their proportion of cytoplasm.

parent cell

SEE: Mother cell.

parietal cell

A large cell on the margin of the gastric glands of the stomach that secretes hydrochloric acid and intrinsic factor.
SYN: SEE: oxyntic cell
SEE: achlorhydria; SEE: anemia, pernicious; SEE: intrinsic factor

phalangeal cell

One of the cells supporting the hair cells of the organ of Corti. These cells form several rows of Deiters cells (outer phalangeal cells) and a single row of inner phalangeal cells.
SEE: Deiters cell (under Deiters, Otto F.C.)

phantom cell

SEE: red cell ghost

pigment cell

Any cell that normally contains pigment granules.

pillar cell

One of two groups of cells (inner and outer) resting on the basement membrane of the organ of Corti in which elongated bodies (pillars) develop. These enclose the inner tunnel (Corti tunnel).

plasma cell

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.
SYN: SEE: effector B cell

plasmacytoid dendritic cell

ABBR: pDC Any of a subset of dendritic cells that, after contact with malignant cells or pathogens, migrate to lymph nodes and lymphoid organs, secrete interferons and other regulatory cytokines, and stimulate cellular immune responses by T lymphocytes. Overactivation of pDCs is commonly identified in autoimmune diseases like systemic lupus erythematosus and systemic sclerosis.

postganglionic cell

SEE: Postganglionic neuron

PP cell

An enteroendocrine cell that is found in the pancreatic islets and produces pancreatic polypeptide.

pre-B cell

The immediate precursor of a lymphocytic B cell.

precursor cell

SEE: Stem cell.

preganglionic cell

SEE: Preganglionic neuron.

prickle 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.

primary cell

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 cell

SEE: germ cell

primordial germ cell

SEE: germ cell

progenitor cell

SEE: A cell (sometimes a stem cell) that produces cells of a particular lineage, e.g., a neuroblast.

prokaryotic cell

A 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

pus cell

A leukocyte present in pus. Pus cells are often degenerated or necrotic.

pyramidal cell

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, 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.

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.

red cell

SEE: Erythrocyte.

red blood cell

ABBR: RBC SEE: Erythrocyte.

regulatory B cell

ABBR: Breg A B lymphocyte that releases interleukin-10 and/or transforming growth factor-beta, and thereby lowers inflammation.

Renshaw cell

SEE: Renshaw cell

resting cell

1. A cell that is not dividing.
SEE: interphase
2. A cell not performing its normal function, e.g., a nerve cell that is not conducting an impulse or a muscle cell that is not contracting.

reticular cell

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.
2. A cell of reticular connective tissue.
SEE: reticular tissue

reticuloendothelial cell

A cell of the mononuclear phagocyte system.
SEE: mononuclear phagocyte system

Rieder cell

SEE: Rieder cell

rod 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

rosehip cell

An inhibitory neuron in the central nervous system. It synapses with pyramidal cells in the cerebral cortex.
SYN: SEE: rosehip neuron

rosette cell

A rose-shaped cluster of phagocytes surrounding lysed nuclear material or red blood cells. Rosette cells occur frequently in blood in which lupus erythematosus (LE) cells are present. Rosette cells are not diagnostic of LE.
SEE: LE cell

Rouget cell

SEE: Rouget cell

S cell

An enteroendocrine cell that is found in the small intestine and produces secretin.

satellite cell

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.
SYN: SEE: amphicyte; SEE: capsule cell

scavenger cell

A phagocyte that cleans up disintegrating tissues or cells.

Schwann cell

SEE: Schwann cell, under Schwann, Theodore

segmented 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

sensory cell

A cell that when stimulated gives rise to nerve impulses that are conveyed to the central nervous system.

septal cell

A type II alveolar cell that is adjacent to a septum of the alveoli and secretes pulmonary surfactant.

serous cell

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

sex cell

SEE: Gamete.

sickle cell

An abnormal erythrocyte shaped like a sickle.
SYN: SEE: drepanocyte
SEE: sickle cell anemia

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signet-ring cell

A vacuolated cell with an off-center nucleus. Mucus-secreting adenocarcinomas usually contain these cells.

skeletal muscle cell

SEE: muscle

smooth muscle cell

SEE: muscle

somatic cell

Any cell that is not a germ cell.

somatic stem cell

SEE: Adult stem cell.

somatostatin cell

SEE: D cell.

spiculed red cell

Crenated red blood cells with surface projections. This is usually a normal variation in red cell equilibrium and is reversible.
SEE: acanthocyte

spider cell

SEE: Astrocyte.

squamous cell

A flat epithelial cell.
SYN: SEE: squamous epithelial cell

squamous epithelial cell

SEE: Squamous cell.

stellate cell

1. A granule cell of the cerebral cortex.
2. Any of the small interneurons found in the outer layer of the cerebellar cortex along with basket cells.
SEE: basket cell (3)

stellate reticuloendothelial cell

A Kupffer cell, one of the macrophages that line the sinusoids of the liver.

stem cell

An embryonic stem cell or an adult stem cell.

Sternberg-Reed cell

SEE: Reed-Sternberg cell

stipple 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 and slow or stop a specific immune response. Also known as “regulatory T cell.”

sustentacular cell

A supporting cell, as in the acoustic macula, organ of Corti, olfactory epithelium, taste buds, or testes.

sympathicotrophic cell

One of the large epithelial cells that occur in groups in the hilus of the ovary. They are thought to be chromaffin cells.

sympathochromaffin cell

A chromaffin cell of ectodermal origin present in the fetal adrenal gland. Sympathetic and medullary cells originate from these cells.

syncytial giant cell

SEE: Giant cell

T 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) 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 (INFγ), one of the strongest stimulators of macrophage activity.
SYN: SEE: T lymphocyte
SEE: immune response; SEE: lymphocyte; SEE: immunological surveillance; SEE: T-cell receptor; SEE: thymocyte
A T cell can only recognize the “foreignness” of antigens after they have been modified by macrophages and other 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.

SEE: cytokine; SEE: cell-mediated immunity

target cell

1. 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
SYN: SEE: codocyte; SEE: leptocyte
2. The cell at which a signal, e.g., hormone or nerve impulse, is aimed.

Descriptive text is not available for this image

TARGET CELLS In hemoglobin C disease (×600)

tart cell

A phagocyte that has ingested the unaltered nuclei of cells. These nuclei can be observed unchanged within the phagocytes.

taste cell

Any of the neuroepithelial cells within a taste bud that are receptors for the sense of taste. Each cell possesses on the free surface a short gustatory hair that projects through the inner taste pore.
SYN: SEE: gustatory cell; SEE: taste receptor cell

taste receptor cell

SEE: Taste cell.

tear-drop cell

An abnormally shaped blood cell, sometimes found on blood smears of patients with bone marrow fibrosis, iron deficiency, or thalassemias.
SYN: SEE: dacrocyte

tendon cell

SEE: Tenocyte.

terminally differentiated cell

A cell sufficiently committed to a particular function that it can no longer divide.

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: they interact actively with adjacent lymphocytes.

thymus cell

Any cell characteristic of the thymus, including thymic epithelial cells and thymocytes.
SEE: thymic epithelial cell; SEE: thymocyte

thyroid cell

Any cell characteristic of the thyroid gland, but usually referring to a thyroid follicular cell.

totipotent cell

An undifferentiated embryonic cell that has the potential to develop into any type of cell.

Touton giant cell

SEE: Touton cell

transitional cell

The stretchable epithelial cells that compose the transitional epithelium, 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 four to six cells thick, and the top transitional cells on the lumenal surface fuse to become larger and polyploid.

trophoblast cell

Any 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 cell

SEE: Mitral cell.

Türk irritation cell

SEE: Türk irritation cell

Tzanck cell

SEE: Tzanck cell

undifferentiated 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.

unipolar cell

A cell with a single cell process.

Vero cell

A lineage of cells isolated from kidney epithelial cells of the African green monkey (Cercopithecus aethiops) and used in cell cultures.

visual cell

A rod cell or cone cell of the retina.
SEE: cone cell; SEE: rod cell

wandering cell

A rarely used term for a cell (such as a macrophage) that moves like an ameba.

white cell

SEE: Leukocyte.

white blood cell

ABBR: WBC SEE: Leukocyte.