Tissues

Tissue

Tissue

Collection of specialized cells organized to perform a function

Germ layers

Forms embryonic discs that is the source of stem cells

Ectoderm

Covers the external surfaces of the body

Endoderm

Lines epithelium of digestive tract (except mouth and anus)

Mesoderm

Lines epithelium of heart, blood & lymph vessels, urinary system, m & f repro system

Basal lamina

Amorphous material where the basal surfaces of the deepest layers of the cell rest

Basal lamina

Separates the epithelium from the connective tissues

Lamina lucida

Lucent layer made of laminin and proteoglycans

Lamina densa

Electron dense layer consisting of collagen type IV and proteoglycans

Lamina interna

Electron lucent layer not always present; consist of collagen type VII, fibronectin thrombospondin and proteoglycans

Lamina fibroreticularis

Layer of extracellular material that contains reticular fibers (200-500nm) where the basal lamina sits in most

Surface epithelium

Epithelial tissue that covers the body surfaces or lines body cavities

Glandular epithelium

Epithelial tissue which are concerned with production of secretions

Simple squamous

Exhibits irregular polygonal outlines and best seen with silver dyes

Lung alveoli, Bowman capsule, blood & lymphatic vessels, luminal surface of heart

Simple squamous (where)

Simple cuboidal

Forms the walls of tubes that carry secretory and excretory products and it regulates ion and water concentration in certain specialized salivary ducts

Salivary glands, collecting tubules of kidney, pancreas, ovary

Simple cuboidal (where)

Stomach, intestines, large ducts of some exocrine glands, uterus, pulmonary bronchi, oviduct

Simple columnar ()

Pseudostratified columnar epithelium

Only appears stratified but is actually composed of single layer of cells of variable shape and height w/nuclei at 2 or more levels

Spongy part of male urethra

Pseudostratified columnar epithelium. ()

Ciliated pseudostraified columnar epithelium

Kind of epithelium that lines the trachea and bronchi

scleroprotein keratin

Superficial strat squam are filled with?

Keratinized stratified squamous

Found mainly in the skin and forms highly specialized barrier against friction, abrasion, infection, and water loss

Oral cavities, esophagus, vagina

Nonkera stratified squamous ()

stratified cuboidal

Relatively rare epithelium lines the ducts of some glands (salivary, sweat)

stratified columnar

Lines the large ducts of some exocrine glands

Transitional epithelium

Intermediate between strat cub and strat squam

Transitional epithelium

Unique to mammals and lines urinary bladder

Microvilli

Finger like projections protruding from apical surface

Microvilli

Lines the small intestine that form fuzzy, fine vertical lines called Striated border

Cilia

Apical surface of the cell that are specialized for transport of fluids or mucus over the surface of the epithelium

Flagella

Tail of the spermatozoon is more than 50nm long and its main function is to propel the cell along the female genital tract

Steriocilia

Microvilli that are as long as cilia but are non-motile

Intercellular junctions

Used by cell to communicate with other cells

Interdigitation

Simplest of these cell to cell attatchments

Zonula occludens

Cell membrane of each epithelial cells at this junction closely sticks to the cell membrane of adjacent cells

Zonula adherens

Cells are very close to each other but they don’t fuse

Desmosome

Don’t form a bond but a “button-like” adhesions; numerous in the keratinized squamous epithelium of the skin

Desmosome

Characterized by a dense plaque of intracellular attachment proteins (Desmoplakins)

Gap junction

Broad areas where apposed plasma membranes are perforated by connexons

Connexons

Allow exchange of ions and small molecules between cells

Hemidesmosomes

Help anchor epithelial cells to the underlying basal lamina (identical to half a desmosome)

Basal infoldings

Basal striations that increase absorbing capacity of a cell

Glandular epithelium

Organized to form the functional component of organs called glands that produce secretions

Endocrine glands

Secretes hormones that contain receptors.

Exists as distinct organs such as adrenals and thyroid glands (ductless)

Exorcrine glands

Deliver secretions via ducts onto the covering or lining epithelium

Unicellular glands

Simplest type of gland composed of a single cell. (Mucous cells or the goblet cells)

Constitute surface and glandular epithelium of the digestive and respiratory tract. Cup shaped

Secretory epithilial sheet

Any covering epithelium where most cells are secretory. Seen in ependyma

Intraepithelial gland

Group of secretory cells in a covering epithelium that gather around a small orifice which serve as duct

Exocrine glands with ducts

Consist of glands with true ducts

merocrine

Release secretion by exocytosis

Major salivary glands

Ex of merocrine

Holocrine

Release secretion that entails destruction of the secretory cells whose remnants are then discharged by the gland together with secretions

Sebaceous gland

Ex of holocrine

Apocrine

Apical part of the secretory cell is released together with the secretory product

Ceruminous gland

Ex of apocrine

Myoepithelial cells

Flattened stellate cells that are between epithelial cells and basal lamina

Sweat glands, mammary glands, lacrimal glands, and major salivary glands

Where is myoepithelial cell present