Histology Flashcards
Stratified
Many layers
Found where protection is important
Found in skin, oesophagus, urethra, bladder
Simple
Single layer
Found in areas of absorption and filtration. Lining of body’s cavities
Simple squamous epithelium (Mesothelium)
Single layer, thin epithelia
Alveoli of lungs. Lines cavities e.g peritoneal, peritoneum
Simple sqaumous (endothelium)
Lining of heart and blood vessels
Simple cubiodal
Large surface area
Secretion and absorption
Glands and Ducts
Simple columnar
Elongated nuclei, lower in cell
Collecting ducts of kidneys, lining of stomach
Simple pseudostratified
Lining of nasal cavity, bronchi
Protection and secretion
Stratified squamous
Surface of skin, oral cavity
Physical protection against abrasion, pathogens and chemical attack
Stratified cuboidal
Lining of some ducts (rare)
Sweat duct gland
Protection, secretion, absorption
Stratified columnar
Mammary glands, salivary glands
Protection
Stratified Transitional
Urinary bladder
Permits expansion and recoil after stretching
Tight junctions
Prevents movement of molecules between cells and prevents movement of apical or basal proteins. Have interlocking proteins called zonula occludens and adherens
Zona Occludens
Scaffolding proteins for the assembly of tight junction complexes and provide link with cytoskeleton
Zona Adherens
Stabilise cell to cell contact.
Regulate actin cytoskeleton
Regulate cell signalling
Contraction pulls microvilli apart, makes it easier for molecules to get down and be absorbed by the cell
Has transmembrane proteins E-cadherin connection to B-catenin
Desmosomes
Linking epithelial cells together and provide strength to layers. Has organized network of keratin
Gap Junctions
Pore - allows movement of molecules
Has 6 connexins form connexon. 2 connexons in adjoining cells
Hemidesmosome
Attach to ECM. Contains integrins as the transmembrane attachment protein. Attaches to intermediate filaments
Lamina propria
Produced by ECM. Loose areolar connective tissue
Lamina fibroreticularus - fibronectin
Basal lamina
Produced by epithelia
Lamina lucida - laminin
Lamina densa - collagen IV
Microvilli
Membrane extensions containing microfilaments. Made of actin proteins and increase surface area
Stereocilia
Membrane extension containing microfilaments. Contain actin filaments and often longer and thicker. Sensory hair cells of inner cells
Cilia
Contain microtubules. Made up of tubulin. 9 pairs of tubules, 2 central tubules. Involved in movement of materials e.g resp tract
Acinar
Large bulbous collection within a small lumen
Tubular
Cells of consistent shape that form a uniform tubular lumen
Unicellular glands
Goblet cells - mucus - lubrication of epithelial layer - protection
Simple Tubular
Intestinal glands
Simple coiled tubular
Eccrine sweat glands
Simple branched tubular
Gastric glands
Simple alveolar (acinar)
Not found in adult
Simple branched alveolar
Sebaceous (oil) glands
Endocrine
Released into bloodstream - acts within the body
Exocrine
released via a duct onto an epithelial surface e.g sweat, sebum
Merocrine
Secretion via exocytois
No part of the gland is lost or damaged
Salivary glands
Apocrine
Budding of off extracellular membrane-bound vesicles
Cell loses part of its cytoplasm during secretion. Mammy galnds
Holocrine
Released via rupture of plasma membrane, destroying cell
Sebaceous glands
