0401 Epithelium Flashcards
• Describe appearance of different types of epithelia seen on light microscopy • Be able to provide different examples of the location of epithelial types in the body • Know basic functions of different types of epithelia • Know the basic appearances and purpose of cilia, microvilli and goblet cells, revise desmosomes
What is epithelial tissue and where is it found
Epithelial tissue is one of the four major tissue types. It lines/covers most body surfaces and can also be found in glands
What is simple squamous epithelium and where is it found
It is a single layer of flat, scale like cells (wider than they are all). It is found in the lungs, kidneys and plueral cavities
What is simple cuboidal epithelium and where is it found
Cuboidal epithelium is characterized by cube-like cells with large, spherical central nuclei (as wide as they are tall). It is found in the lining of kidney ducts and salivary/pancreas ducts
What are cilia? What are it’s functions and where might you find them
Cilia are short extensions of cytoplasm and cell membrane at the free surface. It’s primary function is transportation and mucus secretion. E.g. lining fallopian tubes
What are microvilli? What are it’s functions and where might you find them
Microvilli are closely bunched, tiny projections of the free surface of cells. They have a core of actin filaments and primary function is absorption and secretion. E.g. stomach epithelium
What are goblet cells? What are it’s functions and where might you find them
Goblet cells are modified columnar cells in glands that primarily secrete mucus. E.g.the small and large intestines
What is simple pseudostratified epithelium and where is it found
Pseudostratified epithelium is simple epithelium that looks like >1 layer (all cells must rest on basement membrane). It is responsible for secretion, lubrication, protection and transportation. E.g. respiratory epithelium of bronchus
What is stratified squamous epithelium? What are it’s primary functions?
SSW is when there are 2 or more layers of squamous cells (basal layer is generally cuboidal). It’s functions are mainly protective and can be keratinised (e.g. epidermis of skin) and non-keratinised (lining of mouth)
What is keratin and what is it’s role? Give an example of keratinised and non-keratinised epithelium
Keratin is a tough protective protein which prevents water loss, resists friction and repels bacteria. E.g. keratinised = epidermis of skin , non-keratinised = lining of mouth
What is stratified transitional epithelium? What are it’s primary functions?
Intermediate between stratified cuboidal and stratified squamous (basal cuboidal). Its primary function is protection and distension. E.g. the bladder
What is stratified cuboidal epithelium? What are it’s primary functions?
Multiple layers of cuboidal epithelia. It is a robust lining with minimal absorption and secretion. It can be found in the larger ducts of exocrine glands like salivary glands
What is stratified columnar epithelium? What are it’s primary functions?
Multiple layers of cells with surface columnar epithelia. Its main function is protection and secretion. It is very rare (e.g. part of the male urethra)
What is stratified transitional epithelium? What are it’s primary functions?
Transitional epithelium is epithelium that changes between cuboidal and squamous cells. Its main functions are protective and distension (expandable). E.g. the bladder
What are endocrine glands (e.g.?) and are exocrine glands (e.g.)
Endocrine glands secrete hormones directly into blood (e.g. islet cells of pancreas). Exocrine glands release products onto free surface of skin or into cavities (e.g. sweat and salivary glands)
List some functions of epithelium
Diffusion, protection, containment, excretion, absorption, secretion, contraction, sensation
