Chapter 5: Tissues Flashcards
what are the four types of tissues?
epithelial, connective, muscle, nervous
what are epithelial tissues?
typically tissues lining the body
what are the functions of epithelial cells?
protection, coverage, lining; filters bad, absorbs good, manufactures secretions and excretions
what are characteristics of epithelial cells?
they need to be arranged in a certain way, connect to each other closely, avascular, and some are innervated
how do epithelial face when on an apical surface?
faces the lumen, body cavity, or extremity
how do epithelial face when on a basal surface?
faces basement membrane
how do epithelial cells receive nutrients considering they are avascular?
they receive nutrients through neighboring connective tissue
what are tight epithelial junctions?
plasma membranes attach directly with one another using a protein
what are epithelial desmosomes?
connection plaques extend into the cytoplasm of each cell via tonofilaments
what are epithelial gap junctions?
connexons: channels by which cells share cytoplasm; allows for exchange of ions, nutrients, and electrical signals
What is another name for the basement membrane?
the basal lamina
what does the basement membrane do?
functions as an epithelial cell foundation; provides a support structure; separates epithelial cells from connective tissues underneath
what is the basement membrane made up of?
collagen fibers, produced by epithelial cells
how do epithelial cells receive their nutrients?
through diffusion from the connective tissue across the basement membrane into the cells
what specialized surfaces can epithelial tissue have?
brush boarder, cilia, keratin
what does the brush boarder do for epithelial tissue
increases surface area for absorption
where are brush borders most commonly found?
in the intestine
what does cilia do for epithelial tissues?
move substances across the surface of the cell
where are cilia most commonly found?
on the oviduct or trachea
what does keratin do for epithelial tissues
act as another layer of protection, typically waterproof
where is keratin most commonly found?
in the skin cells
how is one layer of epithelial cells characterized?
as simple
how is more than one layer of epithelial cells characterized?
as stratified
what are the different shapes of epithelial cells?
squamous, cuboidal, columnar, transitional