tissue
collection of specialized cells and the extracellular substances surrounding them
extracellular matrix
noncellular substances surrounding the cells
epithelial, connective, muscle and nervous
four primary tissue types
histology
microscopic study of tissues
biopsy
process of removing tissue sample from patients surgically or with a needle for diagnostic purposes
autopsy
examination of the organs of a dead body to determine the cause of death or to study the changes caused by disease
embryonic tissue
embryonic stem cells
endoderm
mesoderm
ectoderm
embryonic germ layers
endoderm
inner layer; forms the lining of the digestive tract and its derivatives
mesoderm
middle layer; forms tissues such as muscle, bone and blood vessels
ectoderm
outer layer; forms the skin
neuroectoderm
portion of the ectoderm that becomes the nervous system
epithelial tissue (epithelium)
tissue that covers and protects surfaces both inside and outside the body; mostly composed of cells; nonvascular
apical (free) surface
surface of epithelium not attached to other cells
later suface
surface of epithelium attached to other cells
basal surface
the surface attached to the basement membrane in most epithelium
basement membrane
specialized type of extracellular material secreted by epithelial and connective tissue cells; helps attach the cells to the underlying tissue and plays an important role in supporting and guiding cell migration during tissue repair
protecting underlying structures
acting as a barrier
permitting the passage of substances
secreting substances
absorbing substances
major functions of epithelial tissue
connective tissue
consists of cells separated from each other by abundant exracellular matrix
enclosing and separating other tissues
connecting tissues to one another
supporting and moving parts of the body
storing compounds
cushioning and insulating
transporting
protecting
major functions of connective tissue
-blast
creates the extracellular matrix
-cyte
maintains the extracellular matrix
-clast
breaks down the extracellular matrix for remodeling
fibroblast
cells that form fibrous connective tissue
fibrocyte
cells that maintain fibrous connective tissue
chodroblast
forms cartilage
chondrocyte
maintains cartilage
osteoblast
forms bone
osteocyte
maintains bone
osteoclast
breaks down bone
adipose cell (adipocyte)
contains large amounts of lipid; the lipid pushes the rest of the cell contents to the periphery
mast cell
cell that commonly lies beneath membranes in loose connective tissue and along small blood vessels and organs; contain chemicals that are released in response to injury, trauma and infection
white blood cell (leukocyte)
cell that continuously moves from blood vessels into connective tissues; movement increases dramatically in response to injury or infection
macrophage
derived from from monocytes; phagocytizes foreign and injured cell; play a major roll in protecting against infection; can be either fixed or wandering
platelets
fragments of hemopoetic cells containing enzymes and special proteins that function in the clotting process to reduce bleeding from a wound
undifferentiated mesenchymal cell
typical adult stem cell that persists in connective tissue; has the potential to form multiple cells
collagen fibers
protein fibers that consist of collagen; very strong and flexible, but inelastic
reticular fibers
protein fibers that consist of very fine collagen fibers; very short, thin fibers that branch to form a networks that fill spaces between organs
elastic fibers
protein fibers that consist of elastin; have the ability to return to the original shape after being stretched or compressed
collagen
reticular
elastic
types of protein fibers
ground substance
constituted mostly by hyaluronic acid and proteoglycans; background against which collagen fibers are microscopically examined
hyaluronic acid
long, unbranched polysaccharide chain composed of repeated disaccharide units; gives a slippery quality to fluids
proteoglycan monomer
large molecule that consists of glycosaminoglycans; each attached by one end to a protein core
proteoglycan aggregate
proteoglycan monomer attached to a hyaluronic acid
adhesive molecule
holds the proteoglycan aggregate together and to structures such as the plasma membrane
chondronectin
adhesive molecule found in the ground substance of cartilage
osteonectin
adhesive molecule found in the ground substance of bone
fibronectin
adhesive molecule found in the ground substance of fibrous connective tissue