Tissues Flashcards
Tissue
group of similar cells, in close proximity, organized to perform one of more specific functions.
What are the four classes of tissues?
-epithelial
-connective
-muscle
-nervous
What are the 4 functions of epithelia?
-providing physical protection
-control permeability
-provide sensation
-produce specialized secretions
Three specializations of epithelial cells:
-move fluids OVER the epithelium
-move fluids THROUGH the epithelium
-produce secretions
Microvilli
increase surface area, absorption, and secretion
Cilia
move fluids across the epithelium
Simple epithelium
single layer of cells
Stratified epithelium
several layers of cells
Squamous epithelium
flat shaped
Cuboidal epithelium
square shaped
Columnar epithelium
tall shaped
Mesothelium
simple squamous epithelium that lines body cavities
Endothelium
simple squamous epithelium that lines heart and blood vessels
Simple squamous function
absorption and diffusion
stratified squamous function
protects against attacks
simple cuboidal function
secretion and absorption
stratified cuboidal function
make up sweat and mammary glands
simple columnar function
absorption and secretion
pseudostratified columnar epithelium function
involves cilia movement of mucous
stratified columnar function
protection
Endocrine glands
release hormones into interstitial fluid
does not have ducts
Exocrine glands
produce secretions into epithelial surfaces through ducts
ex: breast milk from mild ducts
Merocrine secretion
-produced in the golgi apparatus
-released by vesicles through exocytosis
ex: sweat glands
Apocrine secretion
-produced in the golgi apparatus
-are released by shedding cytoplasm
ex: mammary gland
Holocrine secretion
-released by cells bursting; killing gland cells
-cells are then replaced by stem cells
ex: sebaceous gland