Epithelial Tissue Flashcards
epithelial tissue
tightly cohesive sheets of cells that have several functions depending on their specialization
cover the whole surface of the body, both internal and external
skin, intestine, ducts, secretory glands such as salivary glands, liver, blood vessels
characteristics and functions of epithelial tissue
absorption, secretion, or acting as a barrier
types of epithelial tissue
endoderm, mesoderm, ectoderm
basement membrane
a thin sheet of connective tissue that provides structural support for the epithelium and binds it to neighboring structures
cilia
fine, hair-like outgrowths that help remove dust and foreign bodies from the airways (lungs and nose), also occur in the uterus and Fallopian tubes
capable of rapid rhythmic wavelike beating that causes mucus to move
microvilli
located on the lumen of the mesoderm, helps organs slide past each other
endoderm
internal layer; lung, gastric lining, pancreas, thyroid
endothelium
a simple squamous epithelium. circulatory system lining; heart, arteries, veins, capillaries, sinusoids, and lymphatics
mesothelium
a simple squamous epithelium derived from the mesoderm. lines the major body cavities; peritoneal, pleural, pericardial. lumen is covered in microvilli that allows organs to slide past each other.
monolayer of flattened squamous epithelial cells on a thin basement membrane
squamous
thin flat plates, elliptical nuclei
simple epithelium
one cell layer, typically metabolic epithelia that allow for the transport of ions
stratified epithelium
two or more cell layers thick, such as skin, tend to be defensive rather than metabolic
pleura
lining around the lungs
transitional
urinary tract
peritoneum
lining around the abdominal cavity
mesothelium function
lines the major body cavities; peritoneal, pleural, pericardial, and internal reproductive organs. lumen is covered in microvilli and the cells secrete lubricating fluid that allows organs to slide past each other.
visceral mesothelium
covers the outside of internal organs
parietal mesothelium
covers the body walls
apical surface
surface of the epithelium that faces the lumen
basal surface
surface of the epithelium that attaches to the basement membrane/connective tissue
synthesis
synthesis of proinflammatory cytokines, growth factors, and extracellular matrix for repair
secretion
epithelial tissue in glands secretes chemical substances such as enzymes, hormones, and lubricating fluids
absorption
epithelial lining of the digestive tract absorbs nutrients from digested food
sensory reception
specialized epithelium containing nerve endings can be found in the skin, eyes, ears, nose, and tongue
protection
epithelial cells protect underlying layers from mechanical and chemical damage, bacteria, and loss of water
functions of epithelial tissue
synthesis, secretion, absorption, sensory reception, protection, excretion, diffusion, cleaning, reduction of friction
excretion
kidneys excrete waste products, sweat glands produce sweat
diffusion
simple epithelium allows for the diffusion of gasses, liquids, and nutrients. ex: walls of capillaries and lungs
cleaning
cilliated epithelium helps remove dust from the airways
reduction of friction
smooth, tightly locked epithelial cells help reduce friction between blood and blood vessels
7 types of epithelium
simple squamous, stratified squamous, simple cuboidal, stratified cuboidal, simple columnar, pseudostratified columnar, transitional
simple squamous epithelium
single layer of cells, flat and plate like, joined by intercellular junctions resting on a basement membrane
simple squamous epithelium
single layer of cells, flat and plate like, joined by intercellular junctions resting on a basement membrane
found in alveoli and capillaries for gas exchange, kidney glomerulus for filtration of urine, endothelium of the heart
simple cuboidal epithelium
single layer, cells are cube shaped, protective, forms conduits for gland ducts, or specialized for secretion and absorption, cytoplasm has more mitochondria and endoplasmic reticulum than simple squamous.
found in glands such as the thyroid, ovary surface, renal tubules, eye, pancreas
simple columnar epithelium
single layer, closely packed slender columns, apical surface forms lumen, oval nucleus near base of cells, forms the major ducts of glands, stomach, intestine, gall bladder, bronchi, goblet cells are common (duodenum), nose, ears, taste buds
stratified epithelium
body linings that need to withstand wear an tear, composed of several layers of cells with top cells that are flat and scaly
skin
dry, keratinized stratified epithelium
lining of the mouth
wet, unkeratinized stratified epithelium
stratified squamous
cells nearest the environment are flattened, base looks cuboidal, found in the esophagus and epidermis of the skin
basal lamina
extracellular matrix excreted by the epithelium which separates the epithelium from the connective tissue and provides structural support to the epithelium, is part of the basement membrane
stratified columnar epithelium
cuboidal at the base, columnar near the surface, found in the male urethra and some large ducts in glands
pseudostratified epithelium
single layer of irregular cells that look like multiple layers, common in the respiratory tract, cilliated, goblet cells, nuclei appear at different levels
transitional epithelium
urothelium, found in the urinary tract, a type of stratified epithelium in which apical cells are cuboidal rather than squamous, until stretched when the bladder is full
vein lining
simple squamous epithelium, endoderm
duct lining
simple cuboidal epithelium
desmosomes
mediate lateral cell adhesion by connecting intermediate filaments in one cell to those in another, provide mechanical stability, plentiful in the stratified squamous epithelium of the skin, slightly flexible like Velcro
intermediate junctions
zonula adherens, close to the apical surface, occur at cell to cell junctions, and surround the entire cell
tight junctions
zonula occludens, isolates interior of the body from the exterior, water-tight, seals the gap between epithelial cells, can be found in the small bowel and keeps digested food from passing between cells
gap junctions
allows the passage of small water soluble molecules from cell to cell
Stratified cuboidal
Sweat glands, mammary glands, salivary glands
Kidney
Simple cuboidal, simple squamous
Lungs
Pseudostratified cilliated columnar epithelium, simple squamous
Colon
Simple columnar, goblet cells
Thyroid
Simple cuboidal
Pancreas
Simple cuboidal, simple columnar
Esophagus
Stratified squamous
Epidermis/skin
Stratified squamous
Trachea
Pseudostratified cilliated columnar, goblet cells
Fallopian tube
Pseudostratified cilliated columnar
Breast
Simple cuboidal, stratified cuboidal
