Epithilial tissue Flashcards
who introduced the word epithelium
ruysch
general location
linings of organs and present as glands
content between the cells
little intercellular material
two surfaces of epithelial tissue
free and basal surface
to what is the basal membrane attached to
acellular basement membrane
function of basement membrane
provides elastic support
anchors epithelial tissue to underlying connective tissue for nutrition
function of free surface
to provide protection (either faces bodily fluid or faces the external environment )
parts of basement membrane
basal lamina
reticular or fibrous lamina
basal lamina
has the epithelial tissue to it
made of mucopolysaccharides and glycoprotiens
fibrous lamina
attached to the connective tissue
made of collagen or reticular fibre secreted by the connective tissue
general location of simple epithelium
lining for body cavities, ducts and tubes
types of simple epithelium
squamous cuboidal columnar ciliated psuedostratified glandular
pavement epithelium
squamous epithelium but know so becaus it is closely fitted with a single layer of irregular boundaried flattened cells
has polygonal view from above
nuclei of epithelium (squamous)
central and flat
location of squamous epithelium
walls of blood vessels coelomic cavities alveoli loop of henle for reabsorption bowmans capsule lymph vessels
function of squamous cells
filtration in bowmans capsule
exchange of material between blood vessels and tissues
exchange of gases
type of cells in cuboidal tissue
cubical cells with a central and rounded nuclei
brushbordered cuboidal tissue
has microvilli which are small finger like projections
increases surface area by a lot
location of brushbordered cuboidal tissue
proximal convoluted tube in nephrons
germinal epithelium
testes and ovaries
produces gametes
general location of cuboidal
ducts of glads, thyroid follicles, tubular parts of nephrons
function of cuboidal
secretion and excretion of glands
reabsorption of useful substances (PCT)
type of cells in columnar epithelium
Single layer of tall and Slender cells lying on a basement membrane and the nuclei are somewhat elevated Along the axis of the cell and lies near the base of the cell
Goblet cells
mucus producing epithelium
mucosa or mucous membrane
Epithelium containing mucus secreting cells along with underlying supporting connective tissue
brush border epithelium columnar
The intestinal mucosa bearing microvilli which increase the absorptive surface area are called brush border columnar epithelium
location of columnar epithelium
It is found in the lining of stomach and intestine
function of columnar epithelium
Absorption and secretion
intestinal juice or succus entericus
The secretion of the brush border cells of the mucosa along with the secretion of the Goblet cells constitutes the intestinal juice or succus entericus this juice contains enzyme such as walters life is die peptidases exercise help in the digestion of complex food materials into simple nutrients and are commonly called brush border enzymes
ciliated epithelium
If the column Nora cuboidal cells with Celia which are hair like outgrowth on the free surface they are called ciliated epithelium the epithelium life over a basement membrane the number of Celia varies from one of you too numerous
function of ciliated epithelium
The Seria remain in rhythmic motion and create a current to transport the materials which come in contact with them their function is to move particles or mucus in a specific direction over the epithelium
ciliated cuboidal epitheliuma
Consists of cubical cells which have cilia on the free surface it occurs in smaller bronchioles in respiratory tract it helps in expelling the mucus and particles trapped in IT towards the pharynx
ciliated columnar epithelium
It consists of columnar cells with Celia on the free surface this epithelium occurs in the inner surface of hollow organs like fallopian tubes which are known as oviduct and most of the respiratory tract additional e it helps in expelling the mucus and particles trapped in towards the pharynx
pseudo stratified epithelium
Pseudostratified epithelium is a type of epithelium that do compromising only a single layer of cells has its nuclei position in a manner suggestive of stratified epithelium hence the name pseudo stratified or falsely multilayered
structure of pseudostratified epithelium
It’s cells are columnar but un equal in size the long cell extend upto the free surface the short cells do not reach me out of resurfaced the long sir have an oval nuclear however the short cells have rounded nuclear the mucus secreting Goblet cells also occur in this epithelium the nucleoli at different levels in different cells hence called pseudo stratified
location of psuedotratified epithelium
pseudo stratified non ciliated columnar epithelium tissue is found in urethra of human male and the last ducts of certain glands that is the parotid salivary gland pseudo stratified ciliated columnar epithelium is found in trachea and large bronchi
simple tubular gland
Intestine example crypts of lieberkuhn
simple alveolar where the terminal part forms alveolus
Mucous gland in skin of frog poison gland in toad
simple coiledTubular
Sweat glands
branched tubular
Gastric glands in stomach
branched alveolar
Sebaceous glands
compound tubular
Mammary glands of prototherians
compound saccular alveolar gland
Salivary glands that is the sublingual and submaxillary
compound tubuloalveolar or tubular sacculor
mammary glands pancreas parotid salivary gland cowper’s gland bartholin gland
holocrine glands
Sebaceous gland where the product of secretion is shared with the whole cell leading to its destruction
merocrine gland
The pancreas salivary glands intestinal glands and sweat glands this is when the secretary granules leave the cell by exocytosis very simple diffusion with no loss of other cellular material
apocrine glands
Mammary gland and axillary sweat glands only the apical portion of the cytoplasm is discharged along with the secretary product
stratified non keratinized squamous epithelium
Covers most surfaces such as those of buccal cavity pharynx and oesophagus it has superficial layers of living squamous cells and deeper layers of intellect polygonal cells
stratified keratinized squamous epithelium
Covers the dry surface of skin it has many superficial layers of horney scale like remains of dead squamous cells and several deeper layers of living polygonal cells heavy deposits of the insoluble protein keratin in the dead superficial cells make the epithelium impervious to water and highly resistant to mechanical abrasions
tight junctions are the zonular occludens
Help to stop substances from leaking across the tissue the plasma membrane in the apical parts of the adjacent epithelial cells become tightly packed together or or even fuse to form the tight junctions
interdigitation
These are inter fitting like processes of the cell membrane of the adjacent cells the increase the area of surface contact between the adjacent cells and therefore the adhesion
intercellular bridges
These a minute projections that arise two adjacent cell membrane they make contact with one another
gap junctions
Facilitate the cells to communicate with each other by connecting the cytoplasm of adjacent cells for Rapid transfer of iron small molecules and sometime is big molecules
intermediate junctions or zonula adherens
These usually occurred just below tight junctions the intercellular space at this place is contains a clear low electron density fluid there is a dense plate or structure like structure on cytoplasmic side of each plasma membrane from which find microfilaments of actin and stained into the cytoplasm there is no intercellular filaments between the adjacent cell membranes there is a adhesive material at this point they probably serve anchoring function
desmosomes or macular adherence
Perform cementing to keep the neighbouring cells together these are like zonula adherens but are thicker and stronger and disc like junctions their intracellular protein the plaque like structure are much thicker. the microfilaments which extend from black like structures into the cytoplasm are not a fact in but of Keratin like protein and these microfilaments are called tonofibrils desmosomes serve anchoring function
hemidesmosomes
Like desmosomes but the thickening is on one side
join epithelial cells to basal lamina
