Chapter 4: Tissues Flashcards
what are the 4 basic tissue types?
1.epithelial
2.connective
3.nervous
4.muscular
epithelial tissue function
to cover structures, to line structures, is avascular, and makes up glands
protects
secretes (mucus, hormones, enzymes)
absorbs (nutrients in digestive canal)
excretes (various substances in urinary tract)
filtrates
connective tissue function
to connect
nervous tissue function
for communication, and is also avascular
combines with epithelial tissue to form special organs for smell, hearing, vision, and touch
epithelial tissue
cells arranged in continuous sheets, either single or multiple layers
little intercellular space between adjacent plasma membranes (closely packed + held tightly together)
2 types of epithelial tissue
surface epithelium (covering and lining epithelium)
glandular epithelium (makes up secreting portion of gland)
location of surface epithelium
forms outer covering of the skin and some internal organs
forms inner lining of blood vessels, ducts, and body cavities.
lines respiratory, digestive, urinary, and genital systems
location of glandular epithelium
thyroid gland
suprarenal (adrenal) glands
sweat glands
digestive glands
apical (free) surface
of an epithelial cell faces the body surface, a body cavity, the lumen of internal organ, or a tubular duct that recieves cell secretions.
May contain cilia or microvilli
(most superficial layer of cells)
lateral surface
of an epithelial cell face adjacent cells on either side, may contain tight junctions, adhering junctions, desmosomes, and or gap junctions
basal surface
of an epithelial cell adheres to extracellular materials such as the basement membrane.
hemidesmosomes anchor the basal surface to the basement membrane
(deepest layer of cells)
basement membrane
Found between an epithelial tissue and a connective tissue
It’s a thin extracellular layer that has 2 layers
1. basal lamina
2. reticular lamina
fibroblast
connective tissue cells that produces the protein collagen and produces ground substance
a large flat cell that secretes most of the extracellular matrix of areolar and dense connective tissues
basement membrane functions
Form a surface where epithelial cells migrate during growth or wound healing
Restrict passage of larger molecules between epithelium and connective tissue
Participate in filtration of blood in kidneys
why is epithelial tissue avascular?
(without vessel)
because it relies on blood vessels of adjacent connective tissue to bring nutrients and remove wastes
exchange of substances is by diffusion
how are surface epithelium classified?
according to 2 characteristics
1.arrangement of cell layers
2. shapes of cells
psuedostratified epithelium
may contain cilia and goblet cells
have cell nucelei lie at different levels
actually a simple epithelium because all cells rest on basement membrane
stratified epithelium
have two or more layers of cells that protect underlying tissue in locations where there is considerable wear and tear
simple epithelium
a single layer of cells that function in
diffusion
osmosis
filtrations
secretion
absorption
columnar cells
may have cilia or microvilli
specialized for secretion or absorption
cuboidal cells
may have microvilli and function in secretion or absorption
squamous cells
allows rapid passage of substances through them
transitional cells
change shape
connective tissue
one of the most abundant tissues in the body
binds together
supports
strengthens
protects and insulates other organs
compartmentalizes structures like skeletal muscles
serves as major transport system within the body
primary location of stored energy reserves
