Terms/Definitions- Epithelia Flashcards
Cytoplasm
area between the cell membrane and the nucleus; varies in composition of water, protein, carbohydrates and salts.
Nucleus
area where DNA is transcribed, RNA is synthesized
Golgi Apparatus
receives protein containing transport vesicles from rER on the convex surface and releases secretory vesicles from the concave surface
Endoplasmic reticulum
forms an interconnected network of flattened, membrane-enclosed sacs (cisternae); membranes of the ER are continuous with the outer membrane of the nuclear envelope
Lysosomes
membrane bound structures containing hydrolytic enzymes which help remove debris, spent organelles, and other substances
Mitochondria
produce ATP, signalling, cellular differentiation, cell death, control of cell cycle and cell growth
Cytoskeleton
microfilaments, intermediate filaments and microtubules that provide structure for cell shape and movement
Epithelial cells
typically “lining” cells; form adenomas, carcinomas, adenocarcinomas
Mesenchymal cells
typically “supporting” cells; form sarcomas, other “omas”
“Round” cells
actually mesenchymal cells; form sarcomas; malignant and metastasize quickly
Functions of epithelial cells
Protection, absorption, secretion, selective permeability, surface transport, sensory reception
Simple squamous epithelium
Function: Allows passage of materials by diffusion and filtration in sites where protection is not important; secretes lubricating substances in serosae.
Location: Kidney glomeruli, air sacs of lungs, lining of heart, blood vessels, and lymphatic vessels; lining of ventral body cavity(serosae)
Simple cuboidal epithelium
Function: secretion and absorption
Location: Kidney tubules; ducts and secretory portions of small glands, ovary surface.
Simple columnar epithelium
Function: Absorption; secretion of mucus, enzymes, and other substances; ciliated type propels mucus (or reproductive cells) by ciliated action.
Location: nonciliated type lines most of the digestive tract (stomach to anal canal), gallbladder and excretory ducts of some glands; ciliated variety lines small bronchi, uterine tubes, and some regions of the uterus.
Cell modifications
Goblet cells- produce mucous, found in the respiratory and gastrointestinal tract; Ciliated cells- provide motility, found in the respiratory tract
Stratified squamous epithelium
Function: protects underlying tissues in areas subject to abrasion
Location: nonkeratinized type forms the moist lining of the esophagus, mouth, and vagina; keratinized type forms the epidermis of the skin, a dry membrane.
Stratified columnar epithelium
Function: protection and secretion
Location: rare in the body; small amounts in male urethra and in large ducts of some glands
Transitional epithelium
Function: stretches readily and permits distension of urinary organ by contained urine
Location: lines the ureters, urinary bladder, and part of the urethra
Pseudostratified ciliated columnar epithelium
Function: Secretion, particularly of mucus; propulsion of mucus bu ciliary action.
Location: nonciliated type in male’s sperm-carrying ducts and ducts of large glands; ciliated variety lines the trachea, most of the upper respiratory tract.
Microvilli
short, finger-like projections, non-motile, increase surface area
Cilia
composed of kinocilia (sensory/moveable) and stereocilia (sensory/ears), found in the epididymus
Basement membrane
link contains lamina lucida, basal lamina, and lamina fibroreticularis
Lamina lucida
contains laminin (anchoring filaments)
Basal lamina
Type IV collage, linked to laminin
Lamina fibroreticularis
comprised of anchoring fibrils and interwoven collagen fibers extending from the underlying connective tissues
Desmosomes
link cells together
Zonula adherens
near the apical surface, attach luminal cells together
Zonula occludens
not at apical surface, not as strong
Gap junctions
holes that allow for communication to go through
Stratified cuboidal epithelium
Function: protection
Location: Largest ducts of sweat glands, mammary glands, and salivary glands.
