Chapter 4 Flashcards
tissues
groups of closely associated cells that work together to perform a specific function
epithelium
covering
connective
support
epithelia
specialized tissues that serve to cover the outer and inner surfaces of the body; form most glandular tissues of the body
functions of epithelia
protection - skin - epidermis secretion - kidneys absorption - kidneys filtration - kidneys these processes involve diffusion
special characteristics of epithelia
cellularity - lots of cells
Specialized Contacts - stuck to each other; keeps cells arranged in layers
Polarity - Apical (exposed/skin) & Basal (deep/lower part) surfaces
Basement Membrane &
underlying connective tissue
avascular (no blood supply)
and innervated (have nerve endings and not bleed)
regeneration (replace cells that fall of daily)
other important features of epithelia
CELL JUNCTIONS (help hold cells together) tight junctions adherens junctions desmosomes gap junctions
other important features of epithelia : basal lamina
located at the border between the epithelium and underlying connective tissue;
acts as a filter and assists in regeneration;
combines with connective tissue layer underneath to form the basement membrane (provides place for the cells to sit)
microvilli
fingerlike extensions of apical epithelial cells that serve to increase area (small intestine)
cilia
whiplike extensions of apical surface membranes that serve to move mucus and other substances across the epithelial surface
STUDY THE PICTURE OF LAYERS OF TISSUE IN YOUR NOTES
MAKE SURE YOU KNOW IT
simple
one layer
stratified
more than one layer
how is stratified epithelia named?
shape of the cells in the apical surface (outside)
squamous cells
flattened cells
cuboidal cells
as tall as they are wide
columnar cells
taller than they are wide
what is simple epithelia involved in?
filtration, absorption, secretion, diffusion
what is stratified epithelia involved in?
serves to protect areas of high abrasion (rubbing cells off)
simple squamous epithelia
location: kidneys, air sacs of lungs, blood vessels, and lining of the ventral cavity
function: diffusion and filtration
simple cuboidal epithelia
location: kidneys, ducts and secretory portions of small glands
function: secretion and absorption
simple columnar
location:
nonciliated- digestive tract,
ciliated- lungs
function:
absorption and secretion of mucus and enzymes
~ the ciliated type propels mucus by ciliary action
pseudostratified (fake) columnar
location:
nonciliated- ducts of large glands
ciliated: the upper respiratory tract
function: secretion of mucus, propulsion of mucus by ciliary action (NO ABSORPTION)
stratified squamous epithelia
(outside cells are squamous and deeper cells are cuboidal)
location:
nonkeratinated- lines the esophagus, mouth, and vagina
keratinized: variety forms the epidermis of the skin
function: protects the underlying tissues in areas of high abrasion
stratified cuboidal epithelia
(two layers of cube shaped cells)
location: largest ducts of sweat glands, mammary glands, and salivary glands
function: protection (from body’s own natural secretion)
stratified columnar epithelia
location: rare in the body
function: protection, secretion
transitional epithelia
location: urinary system; bladder, ureters
function: stretches readily and permits distension when containing urine.
glands
produce and secrete special substances ( sweat, oil, hormones)
exocrine glands
secrete their products onto body surfaces and have local effects
unicellular
goblet cells: secrete mucin which combines with water to form mucus
multicellular
intestinal, stomach, oil, salivary, mammary, sweat
endocrine glands
do not have ducts; secrete directly into the tissue fluid that surrounds them (blood); produce hormones, which travel through the bloodstream to target organs. NOT NOT HAVE LOCAL EFFECTS, ITS ALL OVER THE BODY
