Functional histology and structure of epithelium Flashcards
What are the 3 primitive germ layers formed during gastrulation?
Endoderm (inner), mesoderm (middle), ectoderm (outer)
How long after embryo formation does gastrulation occur?
~15 days
What is functional histology?
Study of tissue adaptation to function
Which layers are epithelial cells derived from?
endoderm, mesoderm, ectoderm
Which 2 molecules join individual epithelial cells together in the epithelium?
Sticky adhesion molecules, junctional complexes
What layer do epithelial and endothelial cells grow on?
Basement membrane
What is the function of epithelial cells lining the GI tract?
Absorption
What is the function of epithelial cells in the kidney?
Excretion
What is the function of epithelial cells that line alveolar walls?
Gas exchange
What is the function of epithelial cells that line glands?
Secretion
What are the 6 functions of epithelium?
Gas exchange, secretion, excretion, absorption, surface transport, protection
What is the function of epithelium in skin epidermis?
Protection
What is the function of epithelium lining airways?
Surface transport (of foreign materials inhaled)
What is the difference between simple and stratified epithelium?
Simple epithelium has one layer of epithelial cells which are all anchored to the basement membrane
Stratified epithelium has multiple layers, so not all epithelial cells are anchored to the basement membrane
What is the structure of cells in stratified squamous epithelium?
multiple layers of ordered, flattened cells
What is the structure of cells in stratified columnar epithelium?
multiple layers of ordered, long cells
What is the structure of cells in stratified cuboidal epithelium?
multiple layers of ordered, square cells
What is meant by pseudostratified columnar epithelium?
Gives impression that there are multiple layers, but there is only one true layer as all epithelial cells are anchored to the basement membrane
What is the structure of cells in transitional epithelium?
multiple layers of differently-shaped, disordered, round cells
What other cell type is present in transitional epithelium
Umbrella cells on surface
What cell type composes the simple epithelium of visceral pleura covering lungs?
Mesothelial cells
What is the function of mesothelial cells in the visceral pleura?
Secrete watery serous fluid that lubricates lungs when they expand in respiration