17666478
Description
Flashcards by Mairi Edwards, updated more than 1 year ago
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Created by Mairi Edwards
over 5 years ago
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| Question | Answer |
| What are the 4 main types of tissue in the body | Connective tissue Nervous tissue Muscle Epithelia |
| What is epithelia | Tight, cohesive, sheets of cells that covers the surfaces of the body, usually acting as protection |
| Name the three germinal layers | Endoderm Mesoderm Ectoderm The epithelial layer is derived from all three |
| What is epithelial tissues relation to blood | There is no relation, all epithelial tissue is AVASCULAR |
| All epithelial tissue is polar. Name the different surfaces | The 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 |
| Name the three types of apical specialisations | Microvilli Stereocilia Cilia |
| What is microvilli | Cytoplasmic protrusions - a 'brush border' They are often found on epithelial lining internal passages, with the purpose of increasing surface area |
| What is stereocilia | Similar 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 |
| What is cilia | Motile, 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 |
| What is the role of junctions in epithelial cells | They maintain the epithelium's polarised state and allows the exchange of information and metabolites between cells and the basement membrane |
| What are the three types of junctions in epithelial cells what is there role where are they found | 1. 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 |
| What are desmosomes | A type of anchoring junction |
| What are the 5 functions of eithelial cells | 1. 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 |
| what are the different shapes of epithelial cells | Squamous Cuboidal Columnar Transitional |
| What is simple squamous epilthelium good for and where would you find it | Good 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 |
| What is simple cuboidal epithelium good for and where would you find it | good for diffusion, secretion, and absorption offers a bit more protection than squamous found in kidney tubules and lining of terminal bronchioles |
| What is simple columnar epilthelium good for and where would you find it | good at absorption and secretion offers even more protection than cuboidal found in glands and some ducts, also in the stomach and intestines |
| What is stratified squamous epilthelium good for and where would you find it | good 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 |
| What is stratified squamous epilthelium good for and where would you find it | good at secretion and absorption quite rare found in sweat glad ducts and salivary gland ducts |
| What is stratified columnar epilthelium good for and where would you find it | Good 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 |
| What is pseudostratified columnar epilthelium good for and where would you find it | good at secreting mucus will pretty much always have cilia lines the nasal cavity, pharynx, trachea, etc |
| Wheer is transitional epithelium found | found 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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