Chapter 20 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
Disease caused by abnormal and uncontrolled cell
proliferation, followed by invasion and colonization of body
sites normally reserved for other cells.
cancer
Disease caused by abnormal and uncontrolled cell
proliferation, followed by invasion and colonization of body
sites normally reserved for other cells.
cell junction
Specialized 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 micropibril
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 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
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.
fibronection
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 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.
metastisis
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 (protooncogene) involved in the control of cell growth or division.
organoid
Capable of giving rise to any type of cell or tissue.
plasmodesma
Capable of giving rise to any type of cell or tissue.
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 supressor gene
A gene that in a normal tissue cell inhibits cancerous
behavior. 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.
