surface epithelia Flashcards
(30 cards)
All epithelial tissues are highly vascularized.
False – Epithelial tissues are avascular; they rely on diffusion from underlying connective tissues.
The main function of glandular epithelium is secretion.
True – Glandular epithelium is specialized for secretion (e.g., hormones, enzymes, mucus).
Endocrine glands release their products into ducts.
False – Endocrine glands release products directly into the bloodstream.
Sensory epithelium shares features with both epithelial and nervous tissues.
True – Sensory epithelium contains specialized cells with traits of both tissue types.
Surface epithelium always faces a free surface.
True – This is a defining feature, such as skin or organ cavities.
Stratified epithelial tissues can contain columnar cells in the deepest layers.
False – Stratified epithelia are only classified by the most superficial layer, and only squamous can be stratified.
Tight junctions are essential for maintaining cell polarity.
True – They prevent mixing of apical and basal proteins.
Transitional epithelium is typically found in the respiratory tract.
False – Transitional epithelium is found in the urinary system, especially the bladder.
Simple squamous epithelium allows for gas and nutrient exchange.
True – Its thin, flat shape allows efficient diffusion.
The epidermis of the skin is composed of simple squamous epithelium.
False – It is composed of stratified squamous keratinized epithelium.
Microvilli are motile structures that move mucus along surfaces.
False – Microvilli are non-motile; cilia perform movement.
The pseudostratified columnar epithelium is commonly found in the trachea and epididymis.
True – These are the two key locations for this rare epithelium.
In keratinized stratified squamous epithelium, the superficial cells have lost their nuclei.
True – This is a hallmark of keratinized cells (e.g., skin).
Zonula occludens are a type of occluding junction.
True – They are tight junctions that seal cells together.
Claudins can form channels that regulate ion passage between cells.
True – Claudins can create selective aqueous channels in tight junctions.
The basal membrane is avascular and composed largely of type IV collagen.
True – Type IV collagen forms a supportive network.
Cilia are supported by actin filaments.
False – Cilia are composed of microtubules, unlike actin-based microvilli.
Desmosomes connect adjacent cells through interactions with intermediate filaments.
True – They provide mechanical strength using intermediate filaments like keratin.
Hemidesmosomes link epithelial cells to underlying connective tissue.
True – They anchor the basal domain to the basal membrane.
Goblet cells secrete enzymes into the bloodstream.
False – Goblet cells secrete mucus into the lumen (exocrine secretion).
Cell polarity refers to structural and functional differences between apical and basal surfaces.
True – Cell polarity defines different roles and molecular compositions.
Langerhans cells in the skin are derived from lymphocytes.
False – They come from monocytes, not lymphocytes.
Keratinization provides a waterproof barrier to the skin.
True – Along with lipids, keratin prevents water loss.
In pseudostratified epithelium, all cells reach the basal membrane.
True – Despite appearances, all cells contact the basement membrane.
