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Histology

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epithelium
a sheet of cells that covers a body surface or lines a body cavity
apical surface
upper free surface exposed to the body exterior or the cavity of an internal organ
basal surface
surface exposed to the superficial surface of external organs and the deep surface of the epidermis
microvilli
fingerlike extensions of the plasma surface
cilia
tiny hairlike projections that propel substances along their free surface
basal lamina
noncellular adhesive sheet made of glycoproteins that determines which molecules are allowed to enter the epithelium
reticular lamina
just deep of the basal lamina, belongs to connective tissue
basement membrane
reinforces epithelial sheet, resists stretching and tearing, defines epithelial boundary
simple epithelia
consists of a single cell layer, found where absorption, secretion, and filtration occur
stratified epithelia
consists of two or more cell layers, common in high abrasion areas where protection is important(skin, mouth lining)
squamous cells
flattened and scale-like cells
cuboidal cells
box-like cells
columnar cells
tall and column-shaped
endothelium
simple squamous epithelia that provides slick, friction reducing lining in lymphatic vessels and in all hollow organs of the cardiovascular system
mesothelium
simple squamous epithelia found in serous membranes lining the ventral body cavity and covering its organs
simple squamous epithelium
this is found where filtration and the exchange of substances by diffusion is a priority, cells flattened laterally
simple cuboidal epithelium
the function of this is absorption and secretion, single layer of cells as tall as they are wide
simple columnar epithelium
lines the digestive tract from the stomach through the rectum, important for absorptions and secretion, single layer of tall, closely packed cells
stratified squamous epithelium
functions as a protective surface, cells are constantly being replaced by division of it's basal cells
connective tissue
functions as binding and support, protection, insulation, and transportation
ground substance
unstructured material that fills the space between the cells and contains the fibers
collagen fibers
extremely tough and provide high tensile strength, made from collagen protein
elastic fibers
found where elasticity is needed(skin, lungs, blood vessel walls), fibers stretch and recoil
reticular fibers
supports soft tissue of organs, allows more give than other collagen fibers
macrophages
central actors in the immune system, phagocytize foreign material
loose areolar connective tissue
gel-like matrix with all three fiber types; cells: fibroblasts, macrophages, mast cells, white blood cells
adipose tissue
provides reserve food fuel; insulates against heat loss; supports and protects organs; found under skin in hypodermis, within abdomen, in breasts
brown adipose tissue
fat cells that use lipid fuels to heat the bloodstream to warm the body
dense regular connective tissue
poorly vascularized, makes up tendons and most ligaments
dense irregular connective tissue
found in the skin as the leathery dermis, made of thick collagen fibers arranged irregularly
elastic connective tissue
found in large arteries, allows recoil of tissue following stretching
cartilage
has qualities between dense connective tissue and bone, is avascular, lacks nerve fibers
hyaline cartilage
supports and reinforces, has resilient cushioning properties, resists compressive stress
elastic cartilage
maintains the shape of a structure while allowing great flexibility
fibrocartilage
tensile strength with the ability to absorb compressive shock
bone
supports and protects body structures, rigid, provides cavities for fat storage and blood synthesis
blood
consists of cells in plasma, transports nutrients throughout the body
cardiac muscle tissue
short, branched, striated, single nucleas, connected by intercalated discs
skeletal muscle tissue
long, cylindrical, striated, multinucleate
smooth muscle tissue
short, spindle shaped, non-striated, single central nucleas