Week 4 Epithelial Tissue Flashcards
(24 cards)
What are the roles of epithelial tissue?
Protection, filtration, secretion, absorption, and excretion.
What are key characteristics of epithelial tissue?
Tightly packed cells, avascular, forms sheets, may be single or multilayered.
What is the basement membrane?
A thin layer that epithelial cells sit upon, separating them from underlying tissue.
What is simple epithelium?
A single layer of cells used for absorption, secretion, diffusion, and filtration.
What is stratified epithelium?
Two or more layers of cells mainly for protection.
What is pseudostratified epithelium?
Appears layered due to nuclei at different levels, but all cells touch the basement membrane.
What is transitional epithelium?
Changes shape from cuboidal to flat as organs stretch (e.g., bladder).
Where is simple squamous epithelium found?
Alveoli and Bowman’s capsule – sites of diffusion and filtration.
Where is simple cuboidal epithelium found?
Thyroid gland, kidney tubules – for secretion and absorption.
Where is simple columnar epithelium found?
GI tract, gallbladder – involved in secretion and absorption.
What is the function of ciliated simple columnar epithelium?
Moves mucus and other substances via cilia – found in respiratory tract and fallopian tubes.
Where is keratinized stratified squamous epithelium found?
Skin – provides protection with a layer of dead keratinized cells.
Where is non-keratinized stratified squamous epithelium found?
Wet surfaces – mouth, vagina, oesophagus.
Where is stratified cuboidal epithelium found?
Rare – ducts of sweat glands and oesophageal glands.
Where is stratified columnar epithelium found?
Rare – part of male urethra and ducts of some glands.
What are the two types of glands?
Endocrine (secrete into interstitial fluid/blood) and exocrine (secrete into ducts).
What do endocrine glands secrete?
Hormones – e.g., pituitary, pancreas (islets of Langerhans), adrenal glands.
What do exocrine glands secrete?
Mucus, sweat, saliva, earwax, digestive enzymes, etc.
What is merocrine secretion?
Secretion via exocytosis (e.g., salivary and pancreatic glands).
What is apocrine secretion?
Secretion accumulates at apical surface, which pinches off (e.g., mammary glands).
What is holocrine secretion?
Entire secretory cell ruptures to release product (e.g., sebaceous glands).
What are the structural classifications of exocrine glands?
Tubular, alveolar, or tubuloalveolar; simple (undivided) or compound (branched ducts).
What is the purpose of a Pap smear?
To detect precancerous changes in cervical epithelial cells.
What epithelial change is linked to COPD?
Loss of cilia in respiratory tract, impairing mucus clearance.
