What is the general structural features of epithelium?
-sheets: tightly bound contiguous cells
-no blood vessels
-rich in nerve endings
sharing a common border; touching
gives rise to the oral and nasal mucosae, cornea, epidermis of the skin, and glands of the skin and the mammary glands.
The liver, the pancreas, and the lining of the respiratory and gastrointestinal tract are derived from _________________.
The uriniferous tubules of the kidney, the lining of the male and female reproductive systems, the endothelial lining of the circulatory system, and the mesothelium of the body cavities develop from the ______________ germ layer.
a layer of extracellular matrix secreted by the epithelial cells, on which the epithelium sits
Epithelium stands on __________________ which is an extracellular matrix layer between the epithelium and the underlying connective tissue.
basement membrane (basal lamina)
What does the basement membrane (basal lamina) serve as?
an underlying support and cushion for epithelium
What are the 3 surfaces each epithelial cell has?
1. Free outer (apical) surface
2. Lateral surface
3. Basal surface
What surface of epithelial cells face the surface of the body or the lumen of internal organs?
Free outer (apical) surface
Which surface of epithelial cells is cilia and microvilli located (if present)?
Free outer (apical) surface
What surface of epithelial cells face the adjacent neighboring cells?
Which surface of epithelial cells is junctional complexes located?
What are the types of junctional complexes are located on the lateral surfaces of epithelial cells?
Tight junctions: occluding junctions
Zonulae adherens: adhesive junctions
Desmosomes: adhesive junctions
Gap junctions: communicating junctions
What surface of epithelial cells face the underlying connective tissues?
Which surface of epithelial cells would hemidesmosomes and membrane infoldings be located?
Epithelial tissue is present in what 2 forms?
Cover mainly the external (skin) and internal surfaces of the body.
epithelia lining the blood vessels and lymphatic vessels.
epithelia lining the body cavities
Epithelia that are specialized for secretion. Actually in-growths of covering epithelium, which descend into the underlying connective tissue.
Some of the glandular epithelia have kept their connection (through the ______) with the covering epithelium and are specialized as _________________.
Which epithelia cover the digestive and respiratory tracts?
Which epithelia line the pleura, peritoneum and pericardium?
Glands that delivers their products to the external environment.
Some glandular epithelia have become detached from covering epithelia and form _______________.
Glands that delivers their products to the blood stream.
Epithelial cells found in sensory organs, such as olfactory(nose) and gustatory(taste buds) cells.
Sensory epithelial cells
Epithelial cells found in seminiferous tubules of testis producing sperm.
germinal epithelial cells
Epithelial cells found in sweat, salivary, and mammary glands.
Epithelium originates from what?
One of three primary embryonic germ layers.
What are the three primary embryonic germ layer that epithelium originates from?
The epithelium of the skin is derived from _____________.
The epithelium lining of the body cavity (mesothelium) and the blood or lymphatic vessels (endothelium) are derived from ______________.
The epithelium lining the digestive, respiratory or urinary tract is derived from ____________.
What are the functions of epithelium?
What is the classification of epithelial cells containing only one layer?
What is the classification of epithelial cells containing more than one layer, multiple layers?
What is the classification of cells having a flat, thin shape?
What is the classification of cells having a truncated hexagonal solid shape with a square profile shape and centrally located nuclei?
What is the classification of cells having a tall hexagonal solid shape with ovoidal nuclei?
Single layer of flat cells.
simple squamous epithelium
Single layer of cells shaped like truncated hexagonal solids and a square profile shape.
simple cuboidal epithelium
Single layer of tall cells shaped like hexagonal solids and ovoid nuclei.
Several layers of cells with the surface-most layer possessing nuclei and flat shaped.
stratified squamous epithelium (nonkeratinized)
Several layers of cells with the surface-most layer containing dead, non-nucleated and flate in shape.
stratified squamous epithelium (keratinized)
Multiple layers with the superficial layer comprising of columnar shaped cells.
stratified columnar epithelium
Appearing to be stratified but actually composed of a single layer of cells. Some are broad and narrow and some are tall and reach the surface but all reach the basal lamina with nuclei located at different levels.
Pseudostratified columnar epithelium
Several layers of large dome shaped cells that can become flattened and thinner.