epithelial Flashcards
Aggregated
polyhedral
cells
epithelial
Several types
of fixed and
wandering
cells
conncetive
elongated
contractile
cells
muscle
Elongated
cells with
extremely fine
processes
nervous
Lining of
surface or
body cavities;
glandular
secretion
epithelial
Support and
protection of
tissues/organs
CT
Strong
contraction;
body
movements
MUSCLW
Transmission
of nerve
impulses
NERVOUS
2 CLASSIFICATION OF EPI
SURFACE AND GLANDULAR
The connective tissue that underlies the epithelia
lining the organs of the digestive, respiratory, and
urinary systems
LAMINA PROPRIA
- small evaginations that increase
the are between the two tissues
(protrusions)
Papillae
The region of the cell contacting the ECM and
connective tissue
BASAL POLE
o Faces the connective tissue
o Near Lamina Propria
BASAL POLE
o opposite end, usually facing a space
o Above
o Not connected tip
o Opposite of Basal Pole
APICAL POLE
CELLS AT THE SIDE
LATERAL SURFACE
The basal surface of all epithelia rests on a thin
extracellular, felt-like sheet of macromolecules
BASEMENT MEMBRANE
SEMIPERMEABLE FILTER FOR SUBSTANCE REACHING EPITHELIAL CELLS FROM BELOW
BASEMENT MEMBRANE
COLOR OF BASEMENT MEMBRANE
PINK
2 PARTS OF BASEMENT MEMBRANE
BASAL AND RETICULAR LAMINA
PARTS OF BASAL LAMINA
TYPE IV COLLAGEN.,LAMININ, NIDOGEN&PERLACAN
V. INTERCELLULAR ADHESION & JUNCTIONS
TIGHT, ADHERENT, GAP JUNCTTIONS AND DESMOSOMES
o Also called occluding junction or Zonula occludence
TIGHT JUNCTIONS
form a seal between adjacent cells.
o tight
o seal to prevent leak or flow
TGHT JUNCTIONS
o Zonula Adhesions
ADHERENT JUNCTIONS
o sites of strong cell adhesion.
..
adherent juncttions
o channels for communication between adjacent cells
o Chemical Synapses
gap junctions`
specialized adhesive protein complexes that localize
to intercellular junctions and are responsible for
maintaining the mechanical integrity of tissues.
desmosomes
o “”- cells to basal lamina
Hemidesmosome
B. TRANSMEMBRANE PROTEIN OF JUNCTIONS
- Claudin & Occludin
- Cadherin
- Connexons
ClaOcCaCo
The seal between the two cell membranes is due to
tight interactions between the transmembrane
proteins
o Tight Junctions
- Claudin & Occludin
transmembrane glycoproteins of each cell that bind
each other in the presence of Ca
cadherin
o Gap Junctions
Connexons
o brush or striated border projecting into the lumen
o increase the cells’ surface area
microvilli
Each actin filament is connected by protein fibrin and villin
microvilli
Each actin filament of microvilli is connected by
protein fibrin and villin
a much less common type of apical process, best
seen on the absorptive epithelial cells lining the
male reproductive system
o increase the cells’ surface area, facilitating
absorption
stereocillia
o Seen in Vas deferens and epididymis
stereocillia
long, highly motile apical structures, larger than
microvilli, and containing internal arrays of
microtubules not microfilaments
cillia
➢ - assembly of microtubules
Axoneme
Epithelia can be divided into two main groups:
covering (or
lining) epithelia and secretory (glandular) epithelia
The very thin surface cells of stratified squamous
epithelia can be “keratinized” (packed with keratin
filaments)
- Stratified Squamous Keratinized Epithelium
found mainly in the epidermis of skin, where it helps
prevent dehydration from the tissue
- Stratified Squamous Keratinized Epithelium
lines moist internal cavities (eg, mouth, esophagus,
and vagina) where water loss is not a problem.
- Stratified Squamous Non-Keratinized Epithelium
Rare in the body
o occurs in the excretory ducts of salivary and sweat
glands
- Stratified Cuboidal
seen in the conjunctiva lining the eyelids, where it is
both protective and mucus secreting
- Stratified Columnar
lines much of the urinary tract, extending from the
kidneys to the proximal part of the urethra,
o characterized by a superficial layer of large, dome
like cells sometimes called umbrella cells
- Transitional Epithelium
/urothelium
tall, irregular cells all are attached to the basement
membrane but their nuclei are at different levels and
not all cells extend to the free surface, giving a
stratified appearance.
pseudostratified epithelium
Contains goblet cells and cilia
- Pseudostratified epithelium
Epithelial cells that function mainly to produce and
secrete various macromolecules
glands
may synthesize, store, and release proteins (eg, in
the pancreas), lipids (eg, adrenal, sebaceous
glands), or complexes
secretory cells
o Composed of cells that secretes
substances/products
glandular epi
2 types of glandular epi
exocrine and endocrine
remain connected with the surface epithelium, the
connection forming the tubular ducts lined with
epithelium that deliver the secreted material where it
is used
exocrine g
o lose the connection to their original epithelium and
therefore lack ducts.
endocrine glands
Secretory portions can be ???? (either short or long and
coiled) or ??? (rounded and saclike); either type of secretory
unit may be branched, even if the duct is not branched
Secretory portions can be tubular (either short or long and
coiled) or acinar (rounded and saclike); either type of secretory
unit may be branched, even if the duct is not branched
the most common method of protein or glycoprotein
secretion and involves typical exocytosis from
membrane-bound vesicles or secretory granules.
MEROCRINE SECRETION
EXOCRINE SECRETION TYPES
MEROCRINE SECRETION, HOLOCRINE SECRETION, APOCRINE SECRETION
HOMEPO
cell disruption that releases the product and cell
debris into the gland’s lumen. This is best seen in
the sebaceous glands producing lipid rich material in
skin
HOLOCRINE SECRETION
product accumulates at the cells’ apical ends,
portions of which are then extruded to release the
product together with small amounts of cytoplasm
and cell membrane. Lipid droplets are
APOCRINE SECRETION
ENDOCRINE SIGNAL TYPES
PARACRINE AND AUTOCRINE
ENDOCRINE SIGNALS ARE RENEWED CVUA
MITOSIS
provides a matrix that supports and physically
connects other tissues and cells together to form the
organs of the body
CT
