EPITHELIUM Flashcards
CELL FORMS OF SIMPLE LAYER
Squamous, Cuboidal, Columnar
CELL FORMS OF STRATIFIED
Squamous Keratinized, Squamous Nonkeratinized, Cuboidal, Transitional, Columnar
Functions as facilitate the movement of
the viscera (mesothelium),
active transport by pinocytosis (mesothelium and endothelium), secretion of biologically active molecules (mesothelium)Main Function of Simple Squamous
Simple Squamous
Functions as Covering, Secretion
Simple Cuboidal
Functions as Protection, lubrication, absorption, secretion
Simple Columnar
Functions as Protection; prevents water loss
Stratified Squamous Keratinized
Functions as Protection, secretion; prevents water loss
Stratified Squamous Nonkeratinized
Functions as Protection, secretion
Stratified Cuboidal
Functions as Protection, distensibility
Transitional
Functions as a protection
Stratified Columnar
Functions as Protection, secretion; cilia-
Lamina-mediated transport of particles trapped in mucus out of the air passages
Pseudostratified
Identify what Epithelial Tissue:
Lining of vessels (endothelium); Serous lining of cavities: pericardium, pleura, peritoneum (mesothelium)
Simple Squamous
Identify what Epithelial Tissue:
Covering the ovary, thyroid
Simple Cuboidal
Identify what Epithelial Tissue:
Lining of intestine, gallbladder
Simple Columnar
Identify what Epithelial Tissue:
Epidermis
Stratified Squamous Keratinized
Identify what Epithelial Tissue:
Mouth, esophagus, larynx, vagina, anal canal
Stratified Squamous Nonkeratinized
Identify what Epithelial Tissue:
Sweat glands, developing ovarian follicles
Stratified Cuboidal
Identify what Epithelial Tissue:
Bladder, ureters, renal calyces
Transitional
Identify what Epithelial Tissue:
Conjunctiva
Columnar
Identify what Epithelial Tissue:
Lining of trachea, bronchi, nasal cavity
Pseudostratified
This epithelial tissue lines much of the urinary tract, extending from the kidneys to the proximal part of the urethra, and is characterized by a superficial layer of large, dome-like cells sometimes called umbrella cells
transitional or urothelium
4 basic tissue types
epithelial, connective, muscular, and ner- vous tissues.
What type of tissue is the Lining of surface or body cavities; glandular secretion
Epithelial
What type of tissue Supports and protects tissues/organs
Connective
The connective tissue that underlies the epithelia lining the organs of the digestive, respiratory, and urinary systems is called the
lamina propria.
The area of con- tact between the two tissues may be increased by small evaginations called
papillae
The region of the cell contacting the ECM and connective tissue is called the ________ and the opposite end, usually facing a space, is the __________.
basal pole ; apical pole
Near the epithelial cells is a thin, electron-dense, sheet-like layer of fine fibrils
Basal lamina
beneath basal lamina layer is a more diffuse and fibrous lamina called
reticular lamina
An extracellular membrane that always lies at the interface of epithelial cells and connective tissue.
basement membrane
These are large glycoproteins that attach to transmembrane integrin proteins in the basal cell mem- brane and project through the mesh formed by the type IV collagen.
Laminin
form a seal between adjacent cells.
tight or occluding junctions
are sites of strong cell adhesion.
adherent or anchoring junctions
channels for communication between adjacent cells.
Gap junctions
Cell adhesion is mediated by
cadherins
increase the cells’ surface area, facilitating absorption.
Stereocilia
best seen on the absorptive epithelial cells lining the male reproductive system
stereocilia
much longer and less motile than microvilli, and may show branching distally.
stereocilia
These are are long, highly motile apical structures, larger than microvilli, and containing internal arrays of microtubules not microfilaments
cilia
This is the most common method of protein or glycoprotein secretion and involves typical exocytosis from membrane-bound vesicles or secretory granules.
Merocrine secretion
These cells accumulate product continuously as they enlarge and undergo terminal dif- ferentiation, culminating in complete cell disruption that releases the product and cell debris into the gland’s lumen.
Holocrine secretion
This product accumulates at the cells’ apical ends, portions of which are then extruded to release the product together with small amounts of cytoplasm and cell membrane.
Apocrine secretion
Three basic mechanisms for releasing the product are commonly used by cells specialized for secretion
merocrine, holocrine, apocrine
Epithelia are often specialized for absorption or ________, pinocytosis of material at the apical side and exocytosis at the baso- lateral side (or vice versa).
transcytosis
2 parts of basement membrane
basal lamina and reticular lamina
In the apical structure, there’s a small membrane projection with cores of actin filaments that generally function to increase epithelial cells’ apical surface area for absorption.
Microvili
A type of junction composed of transmembrane integrins attach cells to proteins of the basal lamina.
Hemidesmosomes
A type of junction in points of cell contact where both plasma membranes have numerous hexameric complexes of transmembrane connexons, each forming a channel allowing passage of small molecules from one cell to the other.
Gap junctions
A long microvilli with specialized mechanosensory function in cells of the inner ear and for absorption in tissues of the male reproductive tract.
Stereocilia
The major function in many epithelial cells is synthesis and secre- tion of specialized products; organs composed primarily of such epithelia are called
glands
These glands have epithelial ducts carrying secretions to spe- cific sites; the ducts of simple glands are unbranched and those of compound glands are branched.
Exocrine glands
These glands lack ducts; secreted substances are hormones carried throughout the body by the interstitial fluid and blood, with specificity produced by the hormone receptors of target cells.
Endocrine glands
Exocrine glands producing mucus, or similar individual cells called
goblet cells
Exocrine glands producing largely enzymes (proteins) are called
serous glands
Lungs, Kidney, Liver
Simple Squamous
Kidney tubules, Thyroid Gland
Simple Cuboidal
Small intestine, Stomach Lining and gallbladder
Simple Columnar
Trachea, Bronchial tree, ductus deferens, epididymis
Pseudostratified
Vagina, mouth, esophagus, epidermis
Stratified squamous
Sweat glands, large ducts of exocrine glands, anorectal junction
Stratified cuboidal
Male Urethra, largest ducts of exocrine gland, anorectal junction
Stratified Columnar
Renal Calyces, Ureters, Urethra, Bladder
Transitional
Produces substance that are needed to be secreted out
Glandular Epithelium
These secrete substances and create fibers deposited in the basement membrane
Fibroblasts
2 major links of tight / occluding junctions
CLAUDINS AND OCCLUDINS
2 major links of adherent junctions / zonula adherens
CADHERIN AND CATENIN COMPLEXES
2 major links of desmosomal junctions
DESMOGLEIN AND DESMOCOLLIN
3 TYPES OF SIGNALLING
Endocrine (long distances via blood vessels), Paracrine (nearby cells), Autocrine (self as own receptor).
FUNCTION OF HORMONES:
○ Regulate the chemical composition and volume of the ECF
○ Help regulate metabolism and energy balance
○ Help regulate contraction of smooth muscle and
cardiac muscles and secretion of glands
○ Help maintain activities of immune system
○ Plays role in growth and development
○ Contribute to the basic processes of
reproduction
○ Help maintain homeostasis
3 types of glands
MEROCRINE
APOCRINE
HOLOCRINE
Gland that releases products by means of exocytosis at the apical
end of the secretory cells
Merocrine aka eccrine
Gland that involves the discharge of free, unbroken, membrane- bound vesicles containing secretory product
Apocrine
Gland that involves the discharge of whole secretory cells, with subsequent disintegration of the cells to release the secretory product.
Holocrine aka terminal differentiation
Exocrine glands classified by products
- Serous glands
- Mucous glands
- Mixed Glands
- Sebacous glands
Glands of Lieberkuhn
Under simple tubular glands, forming tubular epithelia, goblet cells also known as intestinal glands.
