Flashcards
Lecture 3 - Epithelia
Cards in this deck (22)
- 1What are the 4 main types of tissue in the bodyConnective tissue
Nervous tissue
Muscle
Epithelia - 2What is epitheliaTight, cohesive, sheets of cells that covers the surfaces of the body, usually acting as protection
- 3Name the three germinal layersEndoderm
Mesoderm
Ectoderm
The epithelial layer is derived from all three - 4What is epithelial tissues relation to bloodThere is no relation, all epithelial tissue is
AVASCULAR - 5All epithelial tissue is polar. Name the different surfacesThe free apical surface - exposed to the environment
The lateral surface - attached to other epithelial cells (the sides)
The basal surface - attached to the basement membrane, which attached epithelia to underlying tissue - 6Name the three types of apical specialisationsMicrovilli
Stereocilia
Cilia - 7What is microvilliCytoplasmic protrusions - a 'brush border'
They are often found on epithelial lining internal passages, with the purpose of increasing surface area - 8What is stereociliaSimilar to microvilli, but longer, clumped together, and non-motile
They act as sensory hair-like cells and are found in places such as the inner ear - 9What is ciliaMotile, hair-like protrusions which beat in co-ordination to move substances over them
there can be several hundred per cell
found on respiratory epithelium and Fallopian tubes - 10What is the role of junctions in epithelial cellsThey maintain the epithelium's polarised state and allows the exchange of information and metabolites between cells and the basement membrane
- 11What are the three types of junctions in epithelial cells what is there role where are they found1. Tight junctions -
Seals cells together to prevent leaking
Found largely in the brain where leakage is deadly
2. Anchoring Junctions -
Mechanically attaches cells to each-other
Found in tissue prone to severe stress e.g. cardiac tissue and skin
3. Gap junctions -
allows for the passage of chemical and electrical signals between cells
found in essentially all epithelial tissue - 12What are desmosomesA type of anchoring junction
- 13What are the 5 functions of eithelial cells1. Protecting underlying structures
2. Permitting the passage of some substances through it
3. Barrier to prevent many substances from moving through it
4. Secreting substances from built in goblet cells
5. Provide sensations to provide information about its environment - 14what are the different shapes of epithelial cellsSquamous
Cuboidal
Columnar
Transitional - 15What is simple squamous epilthelium good for and where would you find itGood at easy diffusion as it is very leaky
can't be anywhere that encounters friction as its just one thin layer
found lining blood vessels and alveoli - 16What is simple cuboidal epithelium good for and where would you find itgood for diffusion, secretion, and absorption
offers a bit more protection than squamous
found in kidney tubules and lining of terminal bronchioles - 17What is simple columnar epilthelium good for and where would you find itgood at absorption and secretion
offers even more protection than cuboidal
found in glands and some ducts, also in the stomach and intestines - 18What is stratified squamous epilthelium good for and where would you find itgood at protection against abrasion and acts as a good barrier against infection
if keritanised, the surface is dry - skin
if non-keritanised, the surface is wet - mouth, oesophagus, anus - 19What is stratified squamous epilthelium good for and where would you find itgood at secretion and absorption
quite rare
found in sweat glad ducts and salivary gland ducts - 20What is stratified columnar epilthelium good for and where would you find itGood for protection and secretion, but not absorption
usually just columnar cells on top with cuboidal/squamous cells below
found in mammary gland ducts and the larynx - 21What is pseudostratified columnar epilthelium good for and where would you find itgood at secreting mucus
will pretty much always have cilia
lines the nasal cavity, pharynx, trachea, etc - 22Wheer is transitional epithelium foundfound the urinary bladder, pelvis of kidney, and superior part of urethra
tolerates stretching and recoil without damage
when stretched, number of layers fluctuates as cells are dragged into a chain
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- different epithelial types discussed
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- Mairi Edwards
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