EPITHELIAL TISSUE

What are the two types of epithelial tissue?

1. covering - outer covering and inner lining

2. glandular - exocrine and endocrine

How are covering epithelia classified?

arrangement and shape

What are the arrangement of epithelial cells?

simple - single-layer

stratified - two or more layers

pseudostratified - appears to have multiple layers but actually doesn’t (all cells in contact with BM

What is the function of simple arrangement?

secretion, absorption, filtration

What is the function of stratified arrangement?

protective

What are the shapes of cells?

squamous (flat and thin)

cuboidal (as tall as wide)

columnar (rectangular)

transitional (stratified epithelium which can change shape from cuboidal to flat)

Where is transitional epithelium located in the body?

BLADDER

What are the features of simple squamous epithelium?

delicate

where there is filtration - kidneys, diffusion - lungs, secretion where slippery surface needed - outer layer of serous membrane

What are the subtypes of simple squamous epithelium?

mesothelium - lines percardial, pleural, peritoneal cavities

endothelium - lines inside of heart and the blood and lymphatic vessels

What is serosa?

mesothelium, cells and connective tissue they are under

What are the features of simple cuboidal?

where there is secretion and absorption

Where is simple cuboidal epithelium located?

pancreas ducts, parts of kidney, ducts of glands, secretory chambers of thyroid

What is cillia?

A membrane modification. It moves all the stuff that needs to be moved inside tubes etc (might be in fallopian tubes, throat)

Where do we see cillia?

simple columnar epithelium

what are the features of non ciliated simple columnar epithelium?

single layer

microvilli on apical surface

have goblet cells (modified columnar cell)

What are the features of ciliated columnar epithelium

single layer

have goblet cells

What are the features of stratified squamous epithelium?

located where mechanical or chemical stresses are severe

What are the two types of stratified squamous epithelium?

keratinised

non keratinised

Where is keratinised stratified squamous epithelium located?

dry trauma areas (skin)

Where is non-keratinised stratified squamous epithelium located?

wet trauma areas (mouth, throat, tongue, oesophagus, anus, vagina)

What are the features of pseudo-stratified columnar epithelium?

can be cilliated or non cilliated

What are the features of ciliated pseudo-stratified columnar epithelium?

secrete mucus from goblet cells and move it

located in most of upper airways

What are the features of non-ciliated pseudo-stratified columnar epithelium?

have no goblet cells

located in larger ducts of glands, epididymis, part of male urethra

absorption and protection

What is glandular epithelia?

single cell or group of cells that secrete substances

Where do endocrine glands secrete?

directly into blood

Where do exocrine glands secrete?

into ducts that empty onto the surface of covering or lining epithelium

What organ has both endocrine and exocrine glandular tissues?

pancreas

Exocrine glands can be single cells or…

multicellular

What are the characteristics used to describe multicellular exocrine glands

structure

structure of secretory area

relationship between the two

a gland is simple if

it has a single duct that does not divide on its way the the gland cells

a gland is compound if

the duct divides one or more times on its way to the gland cells

What is epithelial tissue?

A body tissue that covers the body surface, lines hollow organs, cavities and ducts and forms the glands of the body

What are the key functions of epithelial tissues?

Selective barriers (limit or aid transfer)

Secretory (onto a free surface)

Protective (especially from abrasion)