WEEK 3: Epithelial Tissues (Laboratory) Flashcards
Types of Epithelia. Cells of covering epithelia are organized into one or more layers that cover the surface or line the cavities of an organ.
Covering or Lining Epithelia
Common types of covering epithelia.
Function: Facilitates the movement of the viscera (mesothelium), active transport by pinocytosis (mesothelium and endothelium), secretion of biologically active molecules (mesothelium)
Distribution: Lining vessels (endothelium); Serous lining of cavities; pericardium, pleura, peritoneum (mesothelium)
Simple Squamous Epithelium
Common types of covering epithelia.
Function: Covering, secretion
Distribution: Covering the ovary, thyroid
Simple Cuboidal Epithelium
Common types of covering epithelia.
Function: Protection, lubrication, absorption, secretion.
Distribution: Lining of intestine, gallbladder
Simple Columnar Epithelium
Abundant in the lining of the small intestine and respiratory tract, which secretes lubricating mucus that aids the function of these organs.
Goblet cell
Common types of covering epithelia.
Function: Protection; prevents water loss
Distribution: Epidermis
Stratified Squamous keratinized (dry) Epithelium.
Common types of covering epithelia.
Function: Protection, secretion; prevents water loss
Distribution: Mouth, esophagus, larynx, vagina, anal canal
Stratified Squamous nonkeratinized (moist) Epithelium
Common types of covering epithelia.
Function: Protection, secretion
Distribution: Sweat glands, developing ovarian follicles
Stratified Cuboidal Epithelium
Common types of covering epithelia.
Function: Protection, distensibility
Distribution: Bladder, ureters, renal calyces
Transitional Epithelium or Urothelium (urinary tract)
Common types of covering epithelia.
Function: Protection
Distribution: Conjunctiva lining the eyelids
Stratified Columnar Epithelium
Common types of covering epithelia.
Function: Protection, secretion; cilia-mediated transport of particles trapped in mucus out of the air passages.
Distribution: Lining of trachea, bronchi, nasal cavity
Pseudostratified Epithelium
Types of Epithelia. Are formed by cells specialized to secrete. Molecules to be secreted are generally stored in the cells in small membrane-bound vesicles called secretory granules.
Glandular Epithelia
Glandular Epithelia. Remain connected with the surface epithelium, the connection forming the tubular ducts lined with epithelium that deliver the secreted material where it is used.
Exocrine glands (with ducts)
Glandular Epithelia. Lose the connection to their original epithelium and therefore lack ducts.
Endocrine gland (w/o ducts)
Exocrine Gland (w/ ducts). Contains the cells specialized for secretion.
Secretory portion
Exocrine Gland (w/ ducts). Transport the secretion out of the gland.
Ducts
Based on release of secretory products. This is the most common method of protein or glycoprotein secretion and involves typical exocytosis from membrane-bound vesicles or secretory granules.
Merocrine secretion (Sweat glands, Salivary glands)
Based on release of secretory products. Involves the cell filling with secretory product and then the whole cell being disrupted and shred (Sebaceous glands)
Holocrine secretion
Based on release of secretory products. Secretory product is typically a large lipid droplet and is discharged together with some of the apical cytoplasm and plasmalemma (Mammary gland)_
Apocrine secretion
Exocrine glands with merocrine secretion can be further categorized as. Watery secretions.
Serous
Exocrine glands with merocrine secretion can be further categorized as. Thick secretions (mucin)
Mucous
Endocrine Gland (w/o ducts). Producers of hormones. Diffuse into the blood for circulation and bind specific receptors on target cells elsewhere in the body.
Paracrine
Endocrine Gland (w/o ducts). Producers of hormones. Cells very close to the hormone-secreting cells or on the secreting cell itself.
Autocrine
