Epithelium and glands w/out images Flashcards
exam 2
epithelial cells form _______ with little extracellular space between cells
contiguous sheets
epithelial cells cover and line all
body surfaces and celomic body cavities
Epithelial cells adhere firmly to adjacent cells using cell adhesion molecules that form _________ to prevent the tearing of the epithelium
specialized cell-cell junction
endothelial cells adhere firmly to the underlying _______ using adhesion molecules
connective tissue
extracellular matrix
basement membrane
epithelia are _______; blood vessels that nourish the epithelium are located in the ______ connective tissue
epithelia are avascular; blood vessels that nourish the epithelium are located in the subjacent connective tissue
epithelium cells have ample
nerve endings
epithelium have a high capacity for renewal by _______ especially in epithelia that are subjected to wear and tear such as skin.
stem cells
epithelium cells are diverse, derived from (3) germ layers
(1) ectoderm
(2) mesoderm
(3) endoderm
epithelia have a free
apical surface
epithelial cells exhibit polarization, having _______ ______ with the apical surface being specialized with ________ while the basal surface is specialized for _______ and the lateral specialized for ________
epithelial cells exhibit polarization, having apical-basal polarity with the apical surface being specialized with cilia while the basal surface is specialized for adhesion and the lateral specialized for cell-cell junctions
epithelia are characterized by specific intermediate filaments _________
cytokeratins
Functions of epithelia depend on their
structures
epidermis of the skin provides mechanical protection, waterproofing and insulation
protection
many epithelial cells contain specialized surfaces such as cilia; in the trachea, cilia move mucus away from the lungs toward the oral cavity
surface transport
epithelial cells often have the ability to absorb molecules from their surroundings; epithelial linning of the small intestine
absorption
cells throughout the body are able to secrete products they synthesize for utilization nearby, such as the secretion of mucus by goblet cells throughout the intestinal tract
Secretion
certain epithelial cells are involved in _______, such as those lining the nasal cavity, which are responsible for olfaction
sensory reception
some epithelial cells take products from the apical surface and move them across their cytoplasm for transport across the basolateral surfaces
Trans-epithelial transport
one layer and is found in tissues that are not subjected to extensive wear and tear
simple
simple epithelium is specialized for
absorption and secretion
example of simple layer
endothelium of blood vessels, mesothelium of celomic cavities, alveoli in the lungs
consists of many layers that are subjected to wear and tear
stratified epithelium
examples of stratified epithelium
skin, oral cavity, esophagus, anal canal, and vagina
epithelium cells have (3) shapes
(1) squamous
(2) cuboidal
(3) columnar
which are wider than they are tall, thin, flat and scale-like
squamous
which are approx. equal in height and width, are more or less square-shaped in vertical section
cuboidal
taller than they are wide
columnar
specialized for filtration, diffusion, osmosis, and secretion
simple squamous epithelium
example of simple squamous epithelium
can be found in the heart and vessels including both blood and lymph vessels
if the simple squamous epithelium is found in blood vessels then it is
endothelium
if the simple squamous epithelium is found lining body cavities and covering mesentery
mesothelium
layer of dead tissue
stratum corneum
layers consists of squamous epithelial cells that have undergone apoptosis, leaving behind only a keratin-rich and filled dead cell layer; nuclei and other organelles are absent
stratified squamous keratinizing epithelium (SSKE)
occurs in both thick and thin skin
SSKE
found in less wear-prone areas such as the oral cavity, esophagus, anal canal and vagina
SSNKE
cells produce less keratin and apical squamous cells do not lose their nuclei
stratified squamous non-keratinizing epithelium
single layer that are specialized for secretion and/or absorption
simple cuboidal
where is simple cuboidal found?
kidney tubules, glandular ducts, ovaries, and the thyroid gland
composed multiple layers of cuboidal cells
stratified cuboidal epithelium
Example of stratified cuboidal epithelium
found in the ducts of different glands, such as sweat, mammary and salivary gland
epithelium that may be specialized for secretion and/or absorption. these cells may be ciliated
simple columnar
examples of simple columnar
absorptive cells of the small intestine
composed of two or more layers of cells with columnar surface cells
stratified columnar epithelium
where can the stratified columnar be found?
in the ocular conjunctiva of the eye, parts of the pharynx and anus, and the male urethra
what do stratified columnar participate in?
secretion and protection
consists of a layer of cells that all are in contact with a basement membrane; however, not all cells reach the luminal surface
pseudostratified epithelium
pseudostratified epithelium specialized for protection and also have protected ____________________
basal (stem) cell niche
organ that contains pseudostratified epithelium
trachea
transitional epithelium also called
urothelium
specialized for distension (stretching) and contraction to accommodate the changes in volume of urinary organs
transitional epithelium
why are umbrella cells called like that?
because of their shape since their basal extensions penetrate between other cells
single cells or group of cells, which are specialized for secretion
glands
glands secrete onto an organ/body surface via ducts
exocrine glands
they secrete into the surrounding interstitium where the secretions can enter the blood and be delivered to other parts of the body
endocrine glands
example of unicellular
goblet cells in intestinal or respiratory epithelium
example of multicellular
majority of glands
having ducts that do not branch
simple glands
defined as having ducts that branch repeatedly to form a branched tree
compound gland
form terminal tubular secretory pieces
tubular glands
form terminal rounded, grape-shaped, secretory pieces
acinar glands
produce watery, serum-like secretions that contain various proteins, including enzymes, enzyme precursors, and antimicrobials
serous glands
produce viscous, sticky secretions that aid in lubrication and trapping pathogens
mucous glands
three mode of secretions
(1) merocrine
(2) apocrine
(3) holocrine
mode whereby cells secrete their products by exocytosis
merocrine
method by which goblet cells release mucous secretions
merocrine
involves the decapitation of the apical portion of the cell membrane; in this mode, a portion of the cytoplasm and cell membrane are also released with the secretory product
apocrine
mammary glans, lipid components of milk released by
apocrine secretion
achieved by apoptosis of the secreting cell thus releasing the whole of the cell’s contents
holocrine
secretion that occurs in the sebaceous glands
holocrine secretion
basal bodies
cilia and flagellum
TRUE OR FALSE:
all epithelia contain keratin intermediates
true!
occludins + claudins
zonula occludens
e-cadherins
zonula adherins
desmosomes
macula adherens
connexins-tetraspans intercellular junction
gap junctions
basal lamina contains what type of collagen?
type IV collagen
anchoring fibrils contain what type of collagen?
collagen VII
basket cells/pseudostratified
myoepithelial cells