Histology - Epithelial Tissue Flashcards
Stains
Hematoxylin
Eosin
Hematoxylin
Stains ACIDIC components BLUE
nucleus
chromatin (DNA)
ribosomes
cartilage
elastic fibers
Eosin
Stains BASIC components PINK
cytoplasm
collagen fibers
muscle tissue
mitochondria
Visual Tools
Light Microscope: low detail of cells/organelles/tissue (stain) // think x-ray qual
TEM: high detail, internal cells, organelles (no staining required) // think CT qual
SEM: high detail, cell surface markings // think MRI qual
Tissues of the Body
Epithelial
Connective
Muscle
Nervous
Epithelial Tissue
Covers body/organ surfaces, lines body cavities, forms glands
Cells = tightly connected to each other
3 principal shapes (squamous - flat // cuboidal - round // columnar - tall)
Epithelial Tissue Layers
Avascular
Receives nourishment via diffusion via basement membrane
Basement Membrane
Thin layer that forms btwn different types of tissues
Barrier
Anchor/base for epithelium to sit on top of (continuous dark pink line)
Apical Region
“North Pole”
Faces lumen
Basal Region
“South Pole”
Faces basement membrane
Basolateral Region
East/West coast where cell touches a neighboring cell
Examples
Simple Squamous
Description: Single layer of flattened cells
Fit together like floor tiles
Function: allow substances to pass easily via diffusion/filtration
Location: lung tissue // lining of vessels // membranes of body cavities
Stratified Squamous
Description: multi-layered, cells tightly fit together, mitosis occurs in deeper layers
Function: forms protective barrier // protection against injury
Two Types: keratinized & non-keratinized
Stratified Squamous Non-Keratinized Epithelium
Forms a wet membrane
Location: lines mouth, throat, esophagus, vagina
Stratified Squamous Keratinized Epithelium
Hard waterproof outer barrier // “dry membrane”
Top layer of cells = dead
No nucleus
Cytoplasm = replaced w/ keratin
Location: skin/epidermis
Simple Cuboidal
Description: single layer of cube shaped cells w/ centrally located nuclei
Function: secretion, excretion, absorption
Location: ovaries, kidneys, ducts of glands
Stratified Cuboidal
Description: 2-3 cell layers thick MAXIMUM // rare in body
Function: secretion of fluids in larger glands
Location: ducts of body (exocrine and endocrine)
Simple Columnar
Description: nuclei located at same level
Function: regions where absorption and secretion take place
Location: GI tract
Stratified Columnar
Description: 2 layers of cells; 2 layers of nuclei
Basal cell appears more cuboidal, apical cell appears more columnar
Function: Secretion of mucus
Location: male urethra
