Epithelial Tissues Flashcards
Characteristic #1
In close contact w/ each other => little to no intercellular spaces between them
Always have top (apical) and bottom (basal) layers
Avascular (lack blood vessels) => nutrients must diffuse
Three types (Single)
Squamous, Cuboidal, Columnar
Three types (Stratified)
Squamous, Cuboidal, Columnar,
Single Squamous Structure
Single layer of flat cells with disc-shaped nuclei
Single Squamous F.
Secretes lubricants in serous membranes
Passage of materials by passive diffusion and filtration (e.g. alveoli)
Single Squamous L.
Lungs alveoli
Linings of heart, blood & lymphatic vessels
Single Cuboidal S.
Single-layer of cubes with large, spherical nuclei
Single Cuboidal F.
Absorption & secretion
Single Cuboidal L.
Kidney tubules
Ovary surface
Single Columnar S.
Single-layer of columns with oval nuclei
Some have cilia at apical surfaces & goblet cells
Single Columnar F.
Absorbtion, secretion of mucus, enzymes & other substances
Ciliated type propels mucus or reproductive cells by ciliary actions
Single Columnar L
Non-ciliated form: Lines - Digestive tract, - gallbladder, Ciliated form: Lines - Uterine tubes - Uterus
Stratified Squamous S.
Many layers of cells (squamous in shape)
Deeper layers of cells are cuboidal or columnar
Thickest
2 types:
- Keratinized: contain protective protein keratin
- Non-keratinized: moist lining of body openings
Stratified Squamous F.
Protects underlying tissues from abrasion
Stratified Squamous L.
Keratinized: epidermis
Non-keratinized: lining of esophagus, mouth & vagina
Stratified Cuboidal S.
2 layers of cubes
Stratified Cuboidal F.
Protection
Stratified Cuboidal L.
Largest ducts of sweat glands
Ducts of mammary glands and salivary glands
Stratified Columnar S.
Several layers (basal cells cuboidal, superficial cells elongated) - only observe the apical cells
Stratified Columnar F.
Protection & secretion
Stratified Columnar L.
Rare tissue type
In male urethra & vas deferens, larges ducts of salivary glands, nasopharynx
Transitional Epithelium D.
Basal cells cuboidal or columnar
Superficial cells squamous
Transitional Epithelium F.
stretches and permits distension of bladder
Transitional Epithelium L.
Ureters, urinary bladder & part of urethra
Goblet cells
Produce mucus for internal surfaces
Characteristics #2
High regeneration capacity Innervated Rest on a basement membrane & are held together by tight junctions Lines external & internal surfaces Maybe ciliated or variously specialized
Function
Protects underlying structures from wear/infections, pressure
Absorption, secretion, filtration, ion transport, creates slippery surface