Epithelium Glands I Flashcards
1
Q
name describe the 4 types of tissues
A
- epithelial
- Covers body surfaces, lines body cavities and forms glands
- connective
- underlies or supports other 3 basic tissues structually and functionally
- muscle
- consists of contractile cells and responsible for movement
- nerve
- receives, transmits and integrates information from outside and inside the body to control activities of the body
2
Q
list the general features of epithelium
A
- avascular
- no blood vessels
- oxygen and nutrients by diffusion from underlying connective tissue
- covers exterior body surfaces (skin)
- lines internal closed cavities
- lines body tubes
- forms secretory portion (parenchyma) and ducts of glands
- specialized cells function as receptors for special sense
3
Q
name the 3 principal characteristics of epithelium
A
- cells are closely apposed (next to) and adhere to each other
- specialized cell to cell junctions
- exhibit functional and morphological polarity
- Free surface/apical domain
- lateral domain
- basal domain
- Basal surface attached to underlying basement membrane
- Cell to matrix junctions
4
Q
name the 5 functions of epithelial tissue
A
- Secretion
- ex: columnar epithelium of stomach and gastric glands
- absorption
- ex: columnar epithelium of intestine
- transportation
- transport material on surface of epithelium with motile cilia
- ex: psedustratified ciliated columnar epithelium of trachia
- mechanical protection
- ex: stratified squamous keratinized epithelium of the skin
- receptor function
- receive and transduce external stimuli
- ex: olfactory epithelium of the nasal mucosa
5
Q
list classifications of epithelium
A
- number of cell layers
- 1 cell layer = simple
- 2+ cell layers = stratified
- cell shape of surface, nucleated
- squamous
- width > height
- cuboidal
- width = depth = height
- columnar
- height > width
- squamous
- Speciailization of apical cell surface
- cilia
- microvili
- stereocilia
- keratinized
- nonkeratinized
6
Q
describe simple squamous epithelium
A
- one layer of flat cells attached to basement membrane
- cell width > height
- apical surfaces are typically smooth
- nuclei appear flattened
- major functions
- exchange
- barrier
- lubrication
- typical locations
- lining of heart, blood & lymphatic vessels
- endothelium
- lining body cavities
- mesothelium
- Bowman’s capsule of kidney
- lining respiratory spaces of lung
- lining of heart, blood & lymphatic vessels
7
Q
describe simple cuboidal epithelium
A
- one layer of cuboidal cells attached to the basement membrane
- cell height = width = depth
- nuclei are typically spherical in shape and centrally located
- apical surfaces can be smooth or have microvilli
- some cells have long and abundant microvilli called a “brush border”
- ex: proximal convoluted tubules of kidney
8
Q
name the major functions and typical locations of simple cuboidal epithelium
A
- functions
- absorption
- secretion
- barrier
- typical locations
- small ducts of exocrine glands
- surface of ovary
- kidney tubules
- thyroid follices
- liver hepatocytes
9
Q
describe the simple columnar epithelium
A
- One layer of columnar cells attached to the basement brane
- cell heigh > width
- nuclei are typically oval in shape and lcoated in the basal region
- apical surface may have specializations depending on location and function
- microvilli
- cilia
10
Q
name the major functions and locations of simple columnar epithelium
A
- Functions
- absorption
- secretion
- locations
- stomach
- small intestine
- large intestine
- gallbladder
- uterine tube
11
Q
describe the pseudostratified epithelium
A
- one layer of cells that vary in shape and height
- most cells are columnar, but some are short basal cells (stem cells)
- pseudo = false
- cells appear stratified (2+ layers) but ALL cells are attached to the basement membrane
- confirmed by EM
- cells appear stratified (2+ layers) but ALL cells are attached to the basement membrane
- the apical surface of the columnar cells often have apical specializations
- cilia
- stereocilia
12
Q
name the functions and locations of pseudostratified epithelium
A
- functions
- secretion
- conduit
- absorption
- locations
- trachea & bronchial tree
- male reproductive tract
- ductus deferens
- epididymis
13
Q
describe the stratified squamous epithelium
A
- several layers of cells with squamous cells in the superficial layer
- may be keratinized or non-keratinized depending on location and functional demand
- only the deepest layer of cells is in contact with the basement membrane
- main functions include protection against injury & abrasion and barrier to dehydration and infection
14
Q
name the functions and locations of stratified squamous epithelium
A
- functions
- barrier
- protection
- locations
- esophagus
- vagina
- epidermis
- oral cavity
15
Q
describe stratified cuboidal epithelium
A
- 2-3 layers of cells with cuboidal cells in the superficial layer
- the apical surfaces of superficial cells are often smooth
- basal cell layer attached to the basement membrane
16
Q
name the major functions and locations of stratified cuboidal epithelium
A
- functions
- barrier
- conduit (channel for conveying water or other fluid)
- locations
- sweat gland ducts
- large ducts of exocrine glands
- anorectal junction
17
Q
describe the stratified columnar epithelium
A
- composed of 2 or 3 layers of cells with columnar cells in the superficial layer
- basal layer of cells attached to basement membrane
- not a common type of epithelium
18
Q
name the major functions and locations of stratified columnar epithelium
A
- functions
- barrier
- conduit
- locations
- largest ducts of exocrine glands
- anorectal junction
19
Q
describe the transitional epithelium
A
- stratified epithelium lining urinary tract
- urothelium
- surface cells often are dome-shaped
- umbrella cells
- in empty bladder, basal cells are mostly cuboidal, middle layer polygonal and apical cells bulge into the lumen
- in stretched bladder, thickness is reduced and the superficial cells are flattened (squamous)
- the apical cells have extra cell membrane material near the superficial (apical) surface
- may possess 2 nuclei
20
Q
name the major functions and locations of transitional epithelium
A
- functions
- barrier
- distensible property
- locations
- urinary system
- renal calyces
- ureter
- bladder
- urethra
- urinary system
21
Q
name the apical specializations of cells
A
- cilia
- assist in movement of particles along apical surface
- microvilli
- increases cell surface area to facilitate absorption and secretion
- stereocilia
- increases apical surface area of cell
22
Q
describe cilia (arrangement, function, location)
A
- elongated, motile structures, the core of microtubules
- 5-10 microns in length
- Microtubules are arranged in a consistent array of 2 central microtubules surrounded by 9 peripheral pairs
- cilia arise from electron dense, cylindrical structures called basal bodies (modified centriole - MTOC)
- Function: aiding the transport of material along the surface of cells
- Locations:
- respiratory epithelium
- Fallopian tube
23
Q
difference between cilia and basal body?
A
24
Q
describe microvilli (structure, function, location)
A
- small finger-like projections
- 1-3 microns
- Brush border
- core composed of actin microfilaments (20-30)
- anchored to an actin network structure called the terminal web, which contain microfilaments to stabilize the microvilli
- Functions
- Increasing the apical surface area of the cell
- aid in absorption
- Locations:
- small intestine
- gall bladder
- kidney
25
Q
describe stereocilia (function, structure, location)
A
- elongated microvilli
- up to 120 microns
- Core = actin microfilaments
- function: helps in absorption
- location:
- epididymins
- vas deferens
- inner ear
