Histology - tissues Flashcards
what are the 4 primary tissue types
epithelial
connective
muscle
nervous
what is the difference between epithelial and connective tissue
epithelial:
- lotta cells packed together with barely any extracellular matrix around em
connective:
- few scattered cells surrounded by lotta extracellular matrix
how are tissues classfied
structure
function
extracellular matrix
what are epithelial tissues?
tissues that provide a protective covering of surfaces inside and outside of the body, also forms glands
has 3 different types of surfaces
free / apical
- lines the inside of cavities of tube or duct
basal
- attached to basement memebrane
lateral
- sides of the cells
are epithelial cells vascular or avascular?
avascular b/c they dont have direct blood supply
what is the basement membrane
it holds all of the cells together
extracellular structure that holds cells together and is formed by secretions in epithelium and connective tissue
are epithelial tissues regenerative
yes
what are some functions of the epithelia
- protecting underlying struture (lining mouth)
- acting as barriers (skin)
- permitting passage of substances - filter toxins
secreting substances - pancreas
absorbing stuff - lining of small intestine
what do microvilli do?
increase SA for abs absorption or secretion
- are stationary
what do cilia do?
move materials across cell surface
- can move - wave like action
classification of epithelium
number number of layers of cells
shape of cell on apical surface
number of cell layers
simple = one layer
stratified = more then one layer
pseudostratisfied = appear stratified by all connected to basement membrane
shape of cells
squamous = flat scale like
cuboidal = cube like
columnar = taller then wide
functional characteristics of simple cells
allows diffusion of gases, filtration of blood, secretion and absorption
functional characteristics of stratified cells
protection, particularly against abrasion
functional characteristics of pseudostratified cells
modification of simple, secrete and mucous
squamous
diffusion and acts as filters
cuboidal and columnar
secretion or absorption. may include goblet cells
what do goblet cells do
produce and secrete mucus
what are keratinized cells
outer layer of cells is made up of dead cells that contain keratin
- helps make cells durable and moisture resistant
- skin
what are non-keratinized cells
outer layer of cells are alive and have a fluid covering to it and is moist
- mouth
describe a simple squamous epithelium
- simple layer of flat cells
- in lines blood vessels (endothelium), alveoli of lungs
- diffusion, filtration, secretion
simple cuboidal epithelium
- single layer of cube cells
- in kidney tubule, glands and ducts, surface of ovaries
- secretion and absorption
simple columnar epithelium
- single layer of columnar cells
- in glands, uterus, uterine tubes, stomach, gallbadder, bronchioles and ventricles of brain
- moves particles out o bronchoiced, helps oocyte move through uterine tube by ciliated cells, absorption by cells in the stomach, secretion by glands in stomach
pseudostratified columnar epithelium
- mostly ciliated with goblet cells
- linings upper respiratory tract (ciliated) and male urethra and epididymis (non-ciliated)
