Epithelium Tissue Flashcards
Tightly bound adjacent cells forming sheets covering or lining the body
Epithelium
functions of epithelium tissue
Protection of underlying tissue
transcellular transport of molecules
selective permeability
detection of sensations
The membrane that supports and separates the epithelium from the underlying supporting tissues
Basement membrane
Epithelium are considered ……….. because they get nutrients via capillaries and the basement membrane
Avascular
Describe the surface of the epithelia
Covers all body surfaces and tubes
forms interfaces between different biological compartments
forms continuous sheets comprising one or more layers of cells
cells bound to adjacent via Cell junctions which provide physical strength and mediates the exchange of information and metabolites
classifications of epithelium membranes
- number of cell layers
- types of cell
- special features - cilia, goblet cells
Type of epithelium that is almost found areas involved in selective diffusion and absorption. provides little protection from mechanical abrasions.
Simple Epithelium.
Describe Simple squamous epithelium
Single layers of tightly packed thin polygonal cells
centrally placed bulging nucleus.
lines surfaces involved in passive transport
Which type of simple epithelium have a single layer of truncated hexagonal solids? When viewed in a section perpendicular to the surface, a square-shaped cell with a centrally placed nucleus is seen.
Simple Cuboidal Epithelium.
Describe simple columnar epithelium.
Tall, rectangular cell with Ovoid nuclei located closer to the basal half of the cell.
mostly found in absorptive surfaces or secretary surfaces: e.g digestive tract, gallbladder
A Type of epithelium tissue with a similar view as simple cuboidal epithelium in surface view.
Simple columnar epithelium
name two epithelium cells that are found in absorptive surfaces or secretary surfaces
simple columnar and cuboidal
A finger-like projection of plasma membrane with modified microtubules in its cytoplasm
Cilium
Among Ciliated cells are non-ciliated cells that have ?
Secretary function
A single layer of cells although appear as stratified, all cells are in contact with the basement membrane of the epithelium but not all reach surface of epithelium.
pseudostratified columnar epithelium
difference between pseudostratified and stratified columnar epithelium
pseudostratified epithelia have cilia and stratified almost never have cilia present
Function of stratified epithelium
Mainly have protective function and the degree of stratification depends on the stress of the tissue due to its function
Name the three types of stratified squamous epithelium
- Keratinized
- Non- keratinized
- Para keratinized
Describe the Non- keratinized stratified squamous epithelium
Upper cells are nucleated- Thus non keratinized
They have multiple layers of cells, only the lower one in contact with the basement membrane. The top cell appears flat. The basal layers are cuboidal and the middle cells are polymorphous. Found in mouth, vagina, etc.
Differentiates the keratinized from the keratinized stratified squamous epithelium.
Upper surface composed of keratin which replaces the dead cells of nuclei and cytoplasm
Stratified squamous Epithelium that found in the later of the skin.
Keratinized
what is meant by pyknotic
A cell that have a condensed, shrunken nucleus.
Para keratinized examples
Hard Palate and gingiva
List the stratified squamous epithelium according to their degree of keratinization from high to low
- Keratinized
- Parakeratinized
- Non keratinized
what is stratified cuboidal epithelium number of layers?
two or three layers
Function and where is found in stratified cuboidal epithelium
Merely provides a more robust lining than simple epithelia would
Found in:
Ducts of sweat glands
Larger excretory glands of exocrine glands such as the salivary glands
Stratified columnar epithelium compromise of?
Low polyhedral to cuboidal shaped cells in the deeper layer which is in contact with the basement membrane
A superficial layer of columnar cells
What is transitional epithelium?
Distinct type of epithelium exclusive to the urinary system – lines the urinary tract from the renal calyces to the urethra
Most superficial cells of empty bladder are large, occasionally binucleated and exhibit round dome tops that bulge into the lumen
This dome shape becomes flattened and the epithelium appears thinner when the bladder is distended with urine
Polarized cells have what?
Apical domain and Basolateral domain
differentiates between basolateral and apical domain.
Apical faces the lumen, have cilia or microvilli
Basolateral, attach the basal lamina and have junctions specialization and intercellular interdigitation
What separate apical and basolateral domain
Tight junction
Explain apical domain
Region of an epithelial cell that faces the lumen.
Rich in ion channels, carrier proteins, ATPase, glycoproteins etc.
Region where regulated secretory products are delivered for release.
Has several surface modifications which are functionally necessary.
The only cell in human body that posses flagella
Spermatozoa
Function of flagella
Function in movement as it propels the cell forward
Small finger-like projections emanating from the free surface of the cell into the lumen
Microvilli
Give the functions for the Motile cilia, Primary cilia, goblets cells, Microvilli
Microvilli Increase surface area, major function in transport and absorption.
Motile cilia Specialised function in propelling mucus and other substances over the surface of epithelium via rapid oscillation
Primary cilia Function as sensors for chemical and mechanical signals
Goblets cells Function to produce mucus, which is made from water and mucigen granules (from the cytoplasm of the cell)
Long microvilli found in epididymis and on sensory hair cells of the cochlea
Stereocilia
Modified columnar epithelial cells that secrete mucus and they don’t divide they differentiates
Goblet cells
Found most in mammals and is a single non motile cilium. Name it
Primary cilia
how does a cilia propel the mucus
Propel via beating in a wave-like synchronous rhythm propelling surface films of mucus/fluids in a consistent direction over the epithelial surface.
Are following statements true or false about microvilli
- Absorptive columnar and cuboidal epithelium have closely packed microvilli
- Are in the striated border of intestinal absorptive cells and brush border of kidney proximal tubule cells.
Both are true
The exocrine glands secrete their products via glands
True or False
True
