ch5 cont Flashcards
epithelial cells overview not function
are sheets of closely adhering cells, one or more cells thick
Covers body surfaces and lines body cavities
Upper surface usually exposed to the environment or an internal space in the body
Constitutes most glands
Avascular (does not have blood vessels)
Usually nourished by underlying connective
high mitosis rate
VERY CELLULAR LOW MATRIX
function of epithelial
Protect deeper tissues from injury and infection Produce and release chemical secretions Excrete wastes Absorb chemicals including nutrients Selectively filter substances Sense stimuli
what are the two classifications of epithelial tissue
simple epithelia
- Contain one layer of cells
- Named by shape of cells
- All cells touch basement membrane
stratified epithelia
- Contain more than one layer
- Named by shape of apical cells
- Some cells rest on top of others and do not touch basement membrane
what are the types of simple epithelial
simple squamous (thin scaly cells)
Simple cuboidal (square or round cells)
Simple columnar (tall, narrow cells)
Pseudostratified columnar
- Falsely appears stratified, as some cells taller than others
- Every cell reaches the basement membrane (but not all cells reach the free surface)
what are goblet cells and where are they found
wineglass-shaped mucus-secreting cells
in simple columnar and pseudostratified epithelia
simple squamous epithelium
Single row of thin cells
Permits rapid diffusion or transport of substances
Secretes serous fluid
Locations: alveoli, glomeruli, endothelium, and serosa
FYI
fragile/slick to allow blood to flow (lines heat and lungs)
simple cuboidal epithelium
Single layer of square or round cells
Absorption and secretion, mucus production and movement
Locations: liver, thyroid, mammary and salivary glands, bronchioles, and kidney tubules
FYI
storage container
most glands here
simple columnar epithelium
Single row of tall, narrow cells
Oval nuclei in basal half of cell
Brush border of microvilli, ciliated in some organs, may possess goblet cells
Absorption and secretion; secretion of mucus
Locations: lining of GI tract, uterus, kidney, and uterine tubes
FYI
stomach (prevent digesting self)
-large space between basal and apical surface
ulcer=failed simple columnar
goblet= increase mucous= increase protection
pseudostratified columnar
Looks multilayered, but all cells touch basement membrane
Nuclei at several layers
Has MASSIVE cilia and goblet cells
Secretes and propels mucus
Locations: respiratory tract and portions of male urethra
FYI:
nuclei always try touch basal surfaces
large cilia dead give away
stratified epithelia
name them
MORE THAN ONE LAYWER OF CELLS
Range from 2 to 20 or more layers of cells (can be on top of eachother)
Only the deepest layer attaches to basement membrane
Three stratified epithelia are named for the shapes of their apical surface cells
- Stratified squamous
- Stratified cuboidal
- Stratified columnar (rare)
Fourth type
Transitional epithelium
stratified squamous
is most widespread epithelium in the body
Deepest layers undergo continuous mitosis
Daughter cells push toward the surface and become flatter as they migrate upward
Finally die and flake off—exfoliation or desquamation
Two kinds of stratified squamous epithelia
1. Keratinized—found on skin surface, abrasion resistant
- Nonkeratinized—lacks surface layer of dead cells
keratinized stratified squamous
Multiple cell layers; cells become flat and scaly toward surface
Resists abrasion; retards water loss through skin; resists penetration by pathogenic organisms
Locations: epidermis; palms and soles heavily keratinized
nonkeratinized stratified squamous
Same as keratinized epithelium without surface layer of dead cells
Resists abrasion and penetration of pathogens
Locations: tongue, oral mucosa, esophagus, and vagina
stratified cuboidal epithelium
Two or more cell layers; surface cells square or round
Secretes sweat; produces sperm, produces ovarian hormones
Locations: sweat gland ducts; ovarian follicles and seminiferous tubules
mammary gands
FYI
similar to simple
storage area!
stratified columnar
rare
never more than 4-5 stacked tall
line kidneys and urethra
