Epithelial Tissue Flashcards
What is embryonic origin from mostly ectoderm and endoderm.
Epithelial Tissue
What are some common features of epithelial tissues?
- Avascular
- High capacity for repair
- Always on a connective tissue bed
- Very little or no intercellular substance-closely packed cells.
- Always rests on the basement membrane in between the connective tissue.
What are the types of epithelial tissues based on cell shape?
- Squamous: width of the cell is greater than its height.
- Cuboidal: the width, depth, and height are approximately the same
- Columnar: the height of the cell exceeds its width
What are types of epithelia tissues based on surface additions ?
& cell arrangement ?
- keratin
- cilia
- Microvilli
- simple: when the tissues is one layer thick
- stratified: when the tissues is more than one layer thick
What is simple squamous, cuboidal, and columnar?
- squamous: can be ciliated and is found in capillaries, alveoli of the lungs, Bowman’s capsule of the kidneys.
- cuboidal: non ciliated, found in tubules and ducts.
- columnar: ciliated/non-ciliated, found in digestive tract, gall bladder, and uterine tube.
What is psuedostratified?
the cells appear to be stratified although some cells do not reach the surface.
ciliated/non ciliated: found in the upper respiratory tract, male urethra, and trachea.
What is psuedostratified?
the cells appear to be stratified although some cells do not reach the surface.
ciliated/non ciliated: found in the upper respiratory tract, male urethra, and trachea.
What is stratified squamous, cuboidal, and columnar?
- squamous: most common, keratinized/non keratinized: found in cornea, epidermis, esophagus, and oral cavity.
- cuboidal: sweat glands, large ducts of the exocrine glands.
- columnar: rare, olfactory mucosa, largest ducts of exocrine gland.
What is stratified squamous, cuboidal, and columnar?
- squamous: most common, keratinized/non keratinized: found in cornea, epidermis, esophagus, and oral cavity.
- cuboidal: sweat glands, large ducts of the exocrine glands.
- columnar: rare, olfactory mucosa, largest ducts of exocrine gland.
What is a membrane?
defined as surface epithelium along with its always present underlying connective tissue
What are the two types of membranes?
Mucous membranes: lines the cavities that connect with the outside of the body. (alimentary canal, respiratory tract, and genitourinary tract)
Serous membrane: lines the peritoneal, pericardial, and pleural cavities.
What are the specific names given to epithelium in certain locations?
- Epithelium: covering internal and external surfaces of the body.
- Mesothelium: lining body cavities especially the heart
- Endothelium: lining the lumen of blood and lymphatic vessels.
Where does mesothelium and endothelium come from ? & what does it develop from
Mesothelium and Endothelium come from the mesodermal layer and develops from undifferentiated mesencymal cells.
Where does mesothelium and endothelium come from ? & what does it develop from
Mesothelium and Endothelium come from the mesodermal layer and develops from undifferentiated mesencymal cells.
What is Glandular Epithelium?
Exocrine glands: secrete their products onto a surface directly or through epithelial ducts or tubules that are connected to a surface. Classified as: unicellular (secretory component consists of a single type of cell) multicellular: (composed of more than one secretory cell type) which is further classified as :
simple: the duct is unbranched
compound: the duct is branched
tubular: secretory portion is shaped like a tube.
acinar: secretory portion is shaped like a flask.
Endocrine grands: lack a duct system and secrete directly into tissue from which it enters the blood steam and reaches target cells.
Secretions are called hormones.
What is the rate of cell turnover?
The rate of cell turnover is characteristic of the specific type of epithelium.
What are the functions of the Epithelium?
Protection
Secretion
Excretion
Absorption
Lubrication
Sensory
Reproduction
