PART 1 Flashcards
Epithelium comes from what
the germ layers ( ectoderm . endoderm , mesoderm)
where is the epithelium present
all surfaces and lining the open cavities ex. digestive system and forms secretory portion of glands
what is the epithelium made up of
epithelial cells - keratinocyte in skin and glandular cells in glands.
epithelium function( 7 functions)
1- covering and protection
2- prevents loss of moisture- epidermis
3- absorption - small intestine
4- excretion-sweat glands
5- synthesis of enzymes for digestion - saliva
6- synthesis of hormones - thyroid
7- sensation- taste buds , neuroepithelial of the eye
epithelium that lines the ORAL and NASAL CAVITIES is derived from what
ECTODERM
epithelium that lines the VASCULAR is derived from what
MESODERM
epithelium that lines the DIGESTIVE TRACT AND RESPIRATORY SYSTEM is derived from what
ENDODERM
Name the 3 simple layers
1- simple cuboidal
2- simple columnar
3- simple squamous also know as polyhedral.
Name the 3 stratified layers
1- stratified cuboidal
2- stratified columnar
3- stratified squamous
Define pseudostratified columnar and where can we find it
it appears like its multiple layers because of the height of the nuclei is diff and we can find it in the respiratory tract but there its ciliated.
Where we can we find the transitional epithelium
in urinary bladder
where does the epithelium rests
underlying CT
Two types of underlying CT
dermis - skin so epidermis resting on dermis
lamina propria - internal organs so epithelium on top of lamina propria forming mucosa
what forms the basement membrane
basal lamina + reticular lamina
in LM
we see basement membrane pink like between epithelium and CT ( pa-schiff )
in EM
basal lamina term used
how are the epithelial cells nourished
diffusion of molecules from underlying ct
what is the thickness of basement membrane
20-100nm
basal lamina is secreted by what
epithelial cells
reticular lamina is secreted by what
Connective tissue
what is the composition of basal lamina ( hint they are 4)
1- type 4 collagen
2- glycoproteins ( laminin and entactin)
3-proteoglycan( heparin sulphate )
4- anchoring fibers
what forms the reticular lamina
reticular fibers + basal lamina
basement membrane formed by
2 basal lamina or a basal lamina + reticular lamina
function of Basement Membrane ( 3 functions)
1- supports the epithelium
2- attaches the epithelium to CT
3- nutrition since the diffusion of molecules from CT to epithelial cells must pass through the basement membrane 1st —- then epithelium
WHY does the epithelial cells show modifications of their cell membrane ( hint : they are 2 reasons )
1- help preform cell functions
2- maintain cellular integrity
What are the modifications found on 3 surfaces
1- apical or free surface
2- lateral surface
3- basal surface
List the 3 types of apical surface
1- Microvilli
2- cilia
3- stereocilia
List the 3 types of lateral surface
1- tight junctions
2- adhesion junctions
3- gap junctions
List the 2 types of basal surface
1- hemidesmosomes
2- basal infoldings
Microvilli found where and how high it is and also what is the width
on apical surface
1um high
0.08 um wide
Microvilli seen only by EM or LM
EM
Microvilli is motile or no
no
microvilli doesn’t contain core of actin microfilament true or false
FALSEEEEEEEE WAKE UP
Microvilli found where
columnar cells of intestine
proximal renal tubules
what is the role of actin microfilament in the microvilli
provide support to the plasma membrane
and
maintain morphology of cell
known as brush or striated border in LM
microvilli and the glycocalyx
Where can we find the stereocilia
epididymis of male reproductive - absorption
inner ear - receptor
why is the stereocilia considered microvilli
so because it contains actin microfilament and they name it cilia cuz its tall
stereocilia is motile or non
non motile
Cilia is made up of what
microtubules
Cilia is motile or non
motile
Where can we find cilia
nasal system
upper respiratory system - trachea which is pseudostratified columnar epithelium.
in uterine tube ( simple columnar)
cross section of cilium reveals
9 doublets of microtubules surrounding 2 single microtubules
describe flagella where is it , how many flagella in each cell, and function
flagella only in sperm
one flagella for each cell
and helps in motility
Tight junction is known as
a- zona occludens
b- zonula adherance
c- macula adherance
A. ZONA OCCLUDENS WAKE UPPPPP
Tight junction encircles what
the apical end of the cell tightly like a belt like struCTURE!!!
Tight junction separates what from whatttttt
LUMINAL SPACE FROMN THE INTRACELLUAR SPACE
In tight junction we have exchange of substances between cells true or false?
false
Two types of adhesive junctions
zonula adherence
macula adherance
define adhesive junction
space between 2 plasma membranes of adjacent cells filled by adhesive material (holds the cell together) imagine it like a hot dog the breads at each side is the plasma membrane and the hot dog in the middle is the adhesive material
define Zonula adherance
belt desmosomes
15-20 nm
and insertion of actin microfilaments in cytoplasmic side ( terminal web)
filled with adhesive
define Macula adherance
spot of desmosomes
20-30 nm
filled with adhesive material and intermediate filaments
intermediate filaments attached to the attachment plaques( in epithelium there’s cytokeratin filaments)
Junctional complex is made up of 3 things
zonala occludens
zonula adherance
macula adherance
how do the gap junctions provide communication between cells
by exchanging the materials through plasma membrane
where can we find gap junctions
heart ( cardiac muscle)
how many connexon and made up of what
each 1 connexon( 2nm) made up 6 connexins
what do the gap junctions channels allow
allow the exchange of ions and small molecules between cytoplasm of adjacent cell
What does the hemidesmosomes connect
basal surface of the cell to basement membrane
what anchors the tonofilaments
hemidesmosomes anchor it to basement membrane then to underlying CT
Where is the basal infolding found
kidney tubules
striated salivary glands
function of basal infolding
increase surface area of absorption of cuboidal cells to collect waste products , ions , urea by active transport.
basal infolding It usually associated with large
number of mitochondriae true or false
true
what does the myoepithelial cells cytoplasm
contain actin and myosin filament
why are the myoepithelial cells associated with secretory cells
because when it contracts it facilitate flow of the secretory product example mammary , saliva , sweat
What does the neuroepithelia cells have
modified cilia or microvilli as receptors
can the neuroepithelial cells be replaced after damage
yes they can by basal stem cells
where can we find the neuroepithelial
in sensory organs like olfactory cells and taste buds
