Epithelium Flashcards
Name 3 locations of epithelium
- Covering and lining surfaces
- Covering and lining body tubes
- Glands and ducts
Name 2 epithelium-like tissues
- Endothelium
2. Mesothelium
Name 6 functions of epithelium
- Secretion
- Selective permeability
- Transport
- Absorption
- Protection
- Sensory perception
What are 5 general morphological features of epithelium?
- Cells are closely apposed
- Cells are polarised
- No intercellular spaces
- Basal regions lie on basement membrane
- Usually avascular
What are 3 ways to classify a lining epithelium?
- Number of cell layers
- Shape of most superficial cell with a nucleus
- Surface specialisations
What are 3 shapes of epithelium?
- Columnar
- Squamous
- Cuboidal
What are 3 surface specialisations of epithelium?
- Cilia
- Microvilli
- Keratin
What is simple squamous epithelium?
Single layer of flattened cells
What is the main function of simple squamous epithelium?
Facilitates passive diffusion of gases or fluids
Name 2 places where simple squamous epithelium found
- Lungs
2. Kidney
What is simple cuboidal epithelium?
Single layer of cells where height and width are approximately equal
Name 2 places where simple cuboidal epithelium is found
- Small ducts
2. Tubules
What are the 3 main potential functions of simple cuboidal epithelium?
- Excretion
- Secretion
- Absorption
What is simple columnar epithelium?
Single layer of tall cells with the nucleus located basally
What are the 2 main potential functions of simple columnar epithelium?
- Absorption
2. Secretion
Name 2 places where simple columnar epithelium is found
- GI Tract
2. Large Ducts
What is pseudostratified columnar ciliated epithelium?
Variant of simple columnar where cells appear as many layers but all make contact with basement membrane
Name 2 places where pseudostratified columnar ciliated epithelium is found
- Trachea
2. Bronchus
What is found on the apical surface of stratified squamous non-keratinising epithelium?
Microridges
What is the function of stratified squamous non-keratinising epithelium?
Protection
Name 3 locations of stratified squamous non-keratinising epithelium
- Oral Cavity
- Oesophagus
- Anal Canal
What is the function of stratified squamous keratinising epithelium?
Protection
Name 3 locations of stratified squamous keratinising epithelium
- Epidermis of skin
- Gingiva
- Dorsum of tongue
What is transitional epithelium?
Epithelium which transitions from stratified columnar to stratified squamous
What is the function of transitional epithelium?
Withstand stretch and toxicity of urine
Name 2 locations of transitional epithelium
- Ureter
2. Urinary Bladder
What are the 2 main types of gland?
- Exocrine
2. Endocrine
What is an exocrine gland?
Gland which secretes its products onto a surface via ducts
What is an endocrine gland?
Gland which secretes its products into the blood stream
What are 2 ways to classify an exocrine gland?
- Duct
2. Secretory Unit
What are the 2 classifications of ducts?
- Simple - Unbranched
2. Compound - Branched
What are the 2 classifications of secretory units?
- Acinar
2. Tubular
What are acinar secretory units?
Spherical mass of cells with a central lumen extending into a duct
What shape are acinar secretory units?
Hollow berry
What shape are tubular secretory units?
Test-tube shaped
Give an example of a simple tubular gland
Intestinal glands
Give an example of a simple branched tubular gland
Gastric glands of stomach
Give an example of a simple coiled tubular gland
Sweat glands
Give an example of a simple branched acinar gland
Sebaceous glands
Give an example of a compound tubular gland
Brunner’s glands of duodenum
Give an example of a compound acinar gland
Exocrine portion of pancreas
Give an example of a compound tubuloacinar gland
Submandibular salivary gland
What are the 3 classifications of secretion from exocrine glands?
- Mucous
- Serous
- Seromucous
What substance is found rich in mucous glands?
Mucopolysaccharides
What is the function of mucopolysaccharides?
Lubricate and protect
What substance is found rich in serous glands?
Enzymes
What is the arrangement of cells in a mucous gland?
Cuboidal cells around a central lumen with flattened nuclei at the base
What is the arrangement of cells in a serous gland?
Cuboidal cells around a central lumen with spherical nuclei
What are 3 methods of discharge from a gland?
- Merocrine
- Apocrine
- Holocrine
What are 5 functions of the basement membrane?
- Anchors epithelia
- Defines cell polarity
- Organise protein distribution
- Promote cell survival and differentiation
- Act as scaffold for regenerating cells to adhere to