Epithelial Flashcards
(13 cards)
4 types of tissues
Epithelial
Connective
Muscle
Nervous
Features of epithelial tissue
Little ECM
Layers of closely adhering cells
Flat sheet with upper surface exposed to the environment or an internal body cavity
Cells divide quickly
Avascular 🡪 No blood vessels
Underlying connective tissue provides oxygen and nutrients through diffusion
Rests on basement membrane/ basal lamina
Thin layer of collagen and adhesive proteins
Anchors epithelium to connective tissue
Epithelium tissue function
Covering & Protection
Absorption
Transport
Sensory: nose, ears, taste buds
Secretion
Glands: Exocrine, Endocrine
How is epithelial tissue classified
Based on:
No of cell layers
Shape of cells
Surface of specialisations
Glands
Planes of sectioning
Features of simple epithelia
Single layer
Absorption, secretion, NOT protection
Simple squamous
Simple cuboidal
Simple columnar
Function of simple squamous
passive transport of gas and fluid
found in alveoli, capillaries and glomeruli
Function of simple cuboidal
excretory , secretory or absorptive
found in salivary glands, pancreas
Simple columnar
Highly absorptive or secretory surfaces
Have cilia
Found in gall bladder, fallopian tubes
What does pseudostratified columnar contain
cilia
goblet cells which secrete mucins
nucleus
What’s the function of stratified epithelia
Protection
Two or more layers of cells.
Types:
Stratified squamous, stratified squamous keratinised and transitional
Function of stratified squamous
protects against moderate abrasion
found in moist surfaces like mouth, oesephagus
Function of statified squamous keratinised
protection against constant abrasion
found in skin
Transitional
Ability to stretch and withstand toxicity of urine
found in the urinary tract
