Epithelia and Glands Flashcards
tissue whose cells are bound tightly together structurally & functionally to form a sheetlike or tubular structure with little extracellular material between the cells
epithelial tissue
cells in the epithelial have two sides. what are they?
apical side and basal side
define apical side
side facing the sheet’s free surface
define basal side
side facing a basement membrane and underlying connective tissue
what are the three varieties of epithelial cell nuclei?
- elliptical (oval)
- spherical
- flattened
a type of epithelial tissue that is derived from invagination and in growth of lining epithelia into underlying connective tissue
glands
what is epithelial tissue derived from?
ectoderm, endoderm and mesoderm
epithelial tissue is supported by a __
basement membrane
what are the functions of epithelial tissue?
- Serve as covering, lining, & protecting surfaces (Ex. Epidermis).
- Absorption (Intestinal lining) or transcytosis, pinocytosis of materials at the apical side & exocytosis.
- Secretion ( Parenchymal cells of glands).
what are the three classification of epithelia based on number of cell layer?
- simple
- stratified
- transitional
what are the three classification of epithelia based on the shape of the component cells?
- columnar
- cuboidal
- squamous
what are the two classification of epithelia based on the presence of surface specialisations?
- cilia
- keratin
what is the region of the epithelial cell in contact with the CT?
basal pole
what is the the region of the epithelial cell at the opposite end of the CT usually facing a space?
apical pole
what are the regions of cuboidal or columnar cells that adjoin neighbouring cells?
lateral surfaces
what is the purpose of the numerous infolding in the cell membranes?
to increase the area of the surface, increasing its functional capacity
what are the five types of simple epithelium?
- simple squamous
- simple cuboidal
- simple columnar
- simple columnar ciliated
- pseudo-stratified columnar ciliated
single layer of epithelia whose function is selective diffusion, absorption and secretion?
simple epithelium
type of epithelia that varies from flattened to tall columnar
simple epithelium
type of epithelia that may exhibit variety of surface specialisation
simple epithelia
what are the surface specialisations on simple epithelia?
microvilli and cilia
Found in the air sacs (alveoli), lining of the blood vessels & lymphatics.
simple squamous epithelium
what is the type of epithelia that allows material to pass through by diffusion and filtration?
simple squamous epithelium
what is the type of epithelia that secretes and lubricates substances?
simple squamous epithelium
what is the type of epithelia that lines the thin loops of henle?
simple squamous epithelium
what is the type of epithelium that covers the outer wall of the intestine?
simple squamous epithelium
what is the type of epithelium that lines the inner surface of the cornea?
simple squamous epithelium
what is the type of epithelium found in the ducts s and secretory potions of small glands in the renal tubules?
simple cuboidal epithelium
epithelia whose function is absorption and secretion
simple cuboidal epithelium
what is the type of epithelia found in the renal collecting tubule?
simple cuboidal epithelium
what is the type of epithelium found in the thyroid follicles
simple cuboidal epithelium
what is the type of epithelium found in the thick mesothelium of an ovary?
simple cuboidal epithelium
the type of epithelia whose function is absorption and secretion of mucus and enzymes
simple columnar epithelium
where are simple columnar ciliated epithelial tissues found?
in the bronchus, uterine tubes and uterus
what is the type of epithelium found in the renal collecting duct?
simple columnar epithelium
what is the type of epithelium found in the lining of the oviduct?
simple columnar epithelium
what is the type of epithelium that lines the gall bladder?
simple columnar epithelium
what is the type of epithelium that liens the trachea and other parts of the respiratory tract?
pseudostratified columnar epithelium
what is the function of pseudostratified columnar epithelium?
secretion of mucus
what is the function of ciliated tissue?
move mucus
epithelia that consists of 2 or more layers of cells
stratified epithelium
what is the type of epithelia that serves mainly a protective function and is poorly suited for the functions of absorption and secretion?
stratified epithelium
what is the type of epithelia that lines the esophagus, mouth, and vagina? and what is its function?
stratified squamous epithelia
function- protects the organs from abrasion
what is the type of epithelia found in the sweat glands, salivary glands and mammary glands? what is its function?
stratified cuboidal epithelia
function- protect the tissue
what is the type of epithelia found in the male urethra and some ducts of small glands? what is its function?
stratified columnar
function- secretion and protection
what is the other name for transitional epithelium?
urothelium
lines the urinary tract, extending from the kidneys to the proximal part of the urethra
transitional epithelium
characterised by a superficial layer of large, dome-like rounded cells sometimes called Umbrella cells.
transitional epithelium
allows the urinary organ to expand and stretch
transitional epithelium
lining of vessels, serous lining of cavities, pericardium, pleura, peritonium (mesothelium)
simple squamous epithelium
covers the ovary and thyroid
simple cuboidal epithelium
found in the lining of intestine and gallbladder
simple columnar epithelium
found in the lining of trachea, bronchi, and nasal cavity
pseudostratidied epithelium
found in the epidermis
stratified squamous keritanized
found in the mouth, esophagus, larynx, vagina, anal canal
stratified squamous non-keratinized
found in the sweat glands, developing ovarian follicles
stratified cuboidal
found in the bladder, ureter, renal calyces
stratified transitional
found in conjunctiva
stratified columnar
what are the 3 membrane specialisations of epithelia?
- intercellular surfaces (TAC)
- luminar surfaces
- basal surfaces
what are the 3 types of intercellular surfaces?
- tight junctions
- adhering junctions
- communicating junctions
what are the 4 types of luminar surfaces?
- microvilli
- cilia
- sterocilia
- goblet cells
what are the 2 types of basal surfaces?
- basal membrane
- basal laminar
what is the other name for tight junctions?
occlunding junctions
Most apical & located immediately beneath the luminal surface of simple columnar epithelium.
tight junctions
Forms circumferential band or zonule around the cell.
tight junctions
Formed by interacting transmembrane proteins (Claudin & Occludin)
tight junctions
what surrounds the apical ends of the cell and prevents the paracellular passage of substances (between the cells)?
the linear arrangements of interacting transmembrane proteins
what is the other name for adhering junctions?
anchoring junctions
Provide adhesion of one cell to its neighbor and act as an anchoring site for cytoskeleton of each cell
adhering junctions
Formed by interacting proteins of family are points of strong attachment holding together cells of the epithelium.
adhering junctions
Forms a continuous band (Zonula adherens) or small circular patches or spots (Desmosomes/Macula adherens)
adhering junctions
Are intercellular contact areas containing hundreds of tiny pores which permit passage of small molecules between adjacent cells.
communication junctions
Found in nearly all mammalian tissue except skeletal muscle.
communication junctions
Elongated motile structures that project in parallel rows in the epithelial surfaces
of respiratory & reproductive tracts.
cilia
Surrounded by the cell membrane and contain a central pair of microtubules.
cilia
Symptoms of this disease are chronic respiratory infections caused by the lack of the cleansing action of cilia in the respiratory
tract & immotile spermatozoa, causing male infertility.
immotile cilia syndrome (Kartagener syndrome)
Minute finger-like projections of the luminal plasma membrane
microvilli
They are small membrane projections with cores of Actin filaments.
microvilli
Found in epithelia specialized for absorption and is covered by filamentous coat, the Glycocalyx.
microvilli
A disorder of the small intestine in which one of the 1st pathologic
changes is loss of the microvilli brush border of the absorptive
cells.
celiac disease aka GLUTEN-SENSITIVE ENTEROPATHY or SPRUE
Extremely long non motile microvilli, found in epididymis.
stereocilia
what is the function of stereocilia?
Increase surface area, facilitating the movement of molecules into & out of the cell.
They are modified epithelial cells that secrete mucus on the surface of mucous membranes of organs.
goblet cells
Found in the lower digestive tract & airways and are histologically, mucous merocrine exocrine glands.
goblet cells
what is the basement membrane?
a thin extracellular layer of specialized proteins
what are the two parts of the basement membrane?
- a basal lamina
- a more fibrous reticular laminar
Interface between epithelia & underlying supporting tissue.
basement membrane
a thin meshwork of type IV Collagen & Laminin produced by the epithelial cells.
the basal lamina
Provides structural support for epithelia & constitute a selective barrier to the passage of materials.
the basal lamina
what contains type III collagen & anchoring fibrils of VII collagen, all secreted by cells of the immediately adjacent CT.
the reticular lamina
Invaginations of epithelial surface
glandular epithelium
Discharging their secretions into the free surface via a
duct.
exocrine glands
Ductless glands, secretory products known as hormones pass into the blood stream.
endocrine glands
what is the function of the secretory portion of the exocrine gland?
contains the cells responsible for secretory process; & ducts, which transport the secretion to the exterior of the gland
what are the two types of exocrine gland?
- simple glands
- compound glands
glands with single, unbranched duct
simple glands
glands with branched duct system
compound glands
two types of secretory units found in the secretory portions of exocrine glands
- saclike acini (alveoli)
- elongated tubules
3 glands that help in the discharge of secretory products from the cell
- merocrine gland
- apocrine gland
- holocrine gland
the most common manner of secretion from the cell
merocrine gland
The gland involves process of exocytosis and no part of the gland is lost or damaged.
merocrine gland
protein is the major secretory product of this gland
merocrine gland
the term used to specifically designate merocrine secretions from sweat glands
eccrine
Secretory product is discharged
together with parts of the apical
cytoplasm.
apocrine glands
Most glands are in the skin the armpit, the groin, & the area around the nipples of the breast.
apocrine glands
what are some examples of apocrine glands?
Mammary glands & some
sweat glands in the skin & eyelids
The product of secretion is shed with the whole cells with subsequent disintegration of the
cell to release the secretory product
holocrine gland
what are some examples of holocrine glands?
Sebaceous gland & Meibomian
glands of the eyelids
The ciliated pseudostratified epithelium lining the bronchi of smokers can also be transformed into stratified squamous epithelium in what process?
metaplasia
glands that are the primary structure involved in the common form of acne, ACNE VULGARIS.
the holocrine sebaceous glands
what are malignant tumors of epithelial origin called?
carcinomas
what are malignant tumors derived from glandular epithelial
tissue
adenocarcinomas
the vitamin deficiency that occurs when the epithelial tissues of the type found in the bronchi & urinary bladder are gradually
replaced by stratified squamous epithelium.
chronic vitamin A deficiency
