Ch 20 - Cell Communities; Tissues, Stem Cells and Cancer Flashcards
adherens junction
cell junction that helps hold together epithelial cells in a sheet of epithelium; actin filaments inside the cell attach to its cytoplasmic face
apical
describes the top or the tip of a cell, structure or organ; in an epithelial cell, for example, this surface is opposite the base or basal surface
basal
situated near the base; opposite of apical
basal lamina
thin mat of extracellular matrix, secreted by epithelial cells upon which these cells sit
cadherin
a member of a family of Ca2+-dependent proteins that mediates the attachment of one cell to another in animal tissues
cancer
disease caused by abnormal and uncontrolled cell proliferation, followed by invasion and colonization of body sites normally reserved for other cells
cell junction
specialize region of connection between two cells or between a cell and the extracellular matrix
cell wall
mechanically strong fibrous layer deposited outside the plasma membrane of some cells. prominent in most plants, bacteria, algae and fungi, but not present in most animal cells
cellulose microfibril
long, thin polysaccharide fiber that helps strengthen plant cell walls
collagen
triple-stranded, fibrous protein that is a major component of the extracellular matrix and connective tissues; it is the main protein in animal tissues, and different forms can be found in skin, tendon, bone, cartilage and blood vessels
connective tissue
tissues such as bone, tendons and the dermis of the skin, in which extracellular matrix makes up the bulk of the tissue and carries the mechanical load
desmosome
specialized cell-cell junction, usually formed between two epithelial cells, that serves to connect the ropelike keratin filaments of the adjoining cells, providing tensile strength.
differentiated cell
cell that has undergone a coordinated change in gene expression, enabling it to perform a specialized function
embryonic stem (ES) cell
an undifferentiated cell type derived from the inner cell mass of an early mammalian embryo and capable of differentiating to give rise to any of the specialized cell types in the adult body
epithelium (plural epithelia)
sheet of cells covering an external surface or lining an internal body cavity
extracellular matrix
complex network of polysaccharides (such as glycosaminoglycans or cellulose) and proteins (such as collagen) secreted by cells. a structural component of tissues that also influences their development and physiology
fibroblast
cell type that produces the collagen-rich extracellular matrix in connective tissues such as skin and tendon. proliferates readily in wounded tissue and in tissue culture
fibronectin
extracellular matrix protein that helps cells attach to the matrix by acting as a ‘linker’ that binds to a cell-surface integrin molecule on one end and to a matrix component, such as collagen, on the other
gap junction
in animal tissues, specialized connection between juxtaposed cells through which ions and small molecules can pass from one cell to the other
genetic instability
an increased rate of mutation often caused by defects in the systems that govern the accurate replication and maintenance of the genome; the resulting mutations sometimes drive the evolution of cancer
glycosaminoglycan (GAG)
polysaccharide chain that can form a gel that acts as a ‘space filler’ in the extracellular matrix of connective tissues; helps animal tissues resist compression
hemidesmosome
structure that anchors epithelial cells to the basal lamina beneath them
induced pluripotent stem (iPS) cell
somatic cell that has been reprogrammed to resemble and behave like a pluripotent embryonic stem (ES) cell through the artificial introduction of a set of genes encoding particular transcription regulators
integrin
one of a family of transmembrane proteins present on cell surfaces that enable cells to make and break attachments to the extracellular matrix, allowing them to crawl through a tissue
metastasis
the spread of cancer cells from the initial site of the tumor to form secondary tumors at other sites in the body
oncogene
a gene that, when activated, can potentially make a cell cancerous. typically a mutant form of a normal gene (proto-oncogene) involved in the control of cell growth and division.
organoid
a miniature, three-dimensional collection of tissues formed from the proliferation, differentiation and self-assembly of pluripotent cells in culture
plasmodesma (pl. plasmodesmata)
cell-cell junction that connects one plant cell to the next; consist of a channel of cytoplasm lined by membrane
pluripotent
capable of giving rise to any type of cell or tissue
proteoglycan
molecule consisting of one or more glycosaminoglycan chains attached to a core protein; these aggregates can form gels that regulate the passage of molecules through the extracellular medium and guide cell migration
proto-oncogene
gene that, when mutated or overexpressed, can transform a normal cell into a cancerous one
stem cell
relatively undifferentiated, self-renewing cell that produces daughter cells that can either differentiate into more specialized cell types or can retain the developmental potential of the parent cell
tight junction
cell-cell junction that seals adjacent epithelial cells together, preventing the passage of most dissolved molecules from one side of the epithelial sheet to the other
tissue
cooperative assembly of cells and matrix woven together to form a distinctive multicellular fabric with a specific function
tumor suppressor gene
a gene that in a normal tissue cell inhibits cancerous behaviour. loss or inactivation of both copies of such a gene from a diploid cell can cause it to behave as a cancer cell
Wnt protein
member of a family of extracellular signal molecules that regulates cell proliferation and migration during embryonic development and that maintains stem cells in a proliferative state
