Ch 4 Epithelium

Question 1

Simple Squamous

Answer 1

• -Vascular system-Exchange, barrier sys in CNS
• Bowman’s capsule-Exchange,lubrication,-
• Lung spaces-Barrier
• Body cavities-Exchange

Question 2

Simple Cuboidal

Answer 2

• Small ducts of exocrine gland-Absorption, conduit
• Surface of ovary: Barrier
• Kidney tubules: Absorption,secretory

Question 3

Simple columnar

Answer 3

• Small intestine and colon: absorption, secretion
• Stomach lining and gastric glands; secretion
• Gallbladder: absorption

Question 4

Pseduostratified

Answer 4

• Trachea/bronchial tree:secretion,conduit
• ductus deferens: same
• efferent ductules of epididymis: absorption, conduit

Question 5

stratified squamous

Answer 5

• epidermis: barrier, protection
• oral cavity/esophagus-same
• vagina-same

Question 6

stratified cuboidal

Answer 6

• sweat gland ducts; barrier conduit
• large ducts of excocrine glands: same
• anorectal junction: same

Question 7

stratified columnar

Answer 7

• largest ducts of exocrine glands: barrier, conduit

- anorectal junction

Question 8

transitional (urothelium)

Answer 8

Renal calyces
Ureters
Bladder
Urethra-Barrier,distensible property

Question 9

What are 3 types of junction?

Answer 9

1. Tight junctions (Zone occludens, facia occludens)
2. Adhering, Anchoring junction: Zonula Adherens, Hemidesmosomes, desmosomes
3. Gap junction

Question 10

Give Epithelium functions

Answer 10

• secretion
• absorption
• transport
• protection
• receptor function

Question 11

Types of multicellular glands

Answer 11

• Simple tubular:large intestine,
• Simple coiled tubular: Skin, sweat glands
• Simple branched tubular: Stomach, pylorus, mucous secreting
• Simple acinar: urethra
• Compound tubular: duodenum
• Compound acinar: pancreas, excretory portion
• Compound tubuloacinar: Submandibular salivary gland

Question 12

Give 3 basic release mechanisms

Answer 12

1. Merocrine-to apical, vesicle fusion (pancreatic cells). excocytocis
2. Apocrine: w/ cytoplasm/plasma memb surrounding vesicle (Lactating mammary gland). “Pinching off” of cytoplasm
3. Holocrine: programmed cell death releases product (sebaceous glands in skin). bulk release of whole cells.

Question 13

What does epithelium derive from?

Answer 13

1. ectoderm- skin
2. endoderm - digestive tract
3. mesoderm - serous linings of body cavities
   - mesothelium
   - lining of circulatory system

Question 14

Ex of simple squamous

Answer 14

pulmonary alveoli, parietal layer of Bowman’s capsule, thin segments of Henle’s loop in kidney, rete testis, inner ear, endothelium of blood and lymph vessels

Question 15

ex of simple cuboidal

Answer 15

-follicles of thyroid, surface of ovary, choroids plexus, capsule of lens, pigment epithelium of retina, ducts of glands

Question 16

ex of simple columnar:

-ciliated

Answer 16

• epithelium of digestive tract, large excretory ducts of some glands
• uterus, oviducts, pulmonary bronchi, paranasal sinuses, central canal of spinal cord

Question 17

ex of stratified squamous:

-keratinized

Answer 17

• skin, lining of oral cavity, epiglottis, esophagus, conjunctive and cornea, vagina, distal portion of urethra
• dry scales, exposed surfaces, lose nucleas,

Question 18

ex stratified columnar epithelium:

-ciliated

Answer 18

• fornix of conjunctiva, cavernous urethra, pharynx, small areas of anal mucous membranes, large excretory ducts of salivary glands
• nasal surface of soft palate, larynx, fetal esophagusu

Question 19

ex of pseudostratified:

-ciliated

Answer 19

• male urethra, excretory duct of parotid gland

- trachea, primary bronchii, auditory tubes, part of tympanic membrane, lacrimal sac

Question 20

ex of transitional (uroepithelium)

Answer 20

-urinary bladder:
empty-many layers, distended-2 layers

-urinary tract-renal calyxes of urethra

Question 21

Tight of occluding junctions:

• zonula occludens
• fascia occludens

Answer 21

-partitioning function of connecting ridges that occlude intercellular space; selective seal

• continuous belt-like, made up of integral membrane proteins, selective diffusion barrier
  
  • actin filaments
    - occludens

-interrupted tight junctions, strip or band-shaped ex endothelial cells of blood vessels
-

Question 22

Adhering or Anchoring junctions:

1. Zonula adherens or adhesion belt
2. Macula adherens or Desmosomes
3. Gap Junctions

Answer 22

1. -below zonula occludens
   
   • “terminal bars together with occludens
   • slight e- dense material contain adhesion domains of cell membrane glycoproteins
   • major site of anchorage of microfilaments
   • lateral adhesion
   • cadherin-catehin complex + vinculin & alpha-actinin -> actin filaments
   • calcium-dependent
2. -circular and spot-like
   
   • separate plaques arranged in row
   • convergence of intermediate filaments by attachment plaques
   • transmembrane linker glycoproteins bind adj identical molecules of neighboring cell-strong cell-to-cell adhesion (cahedrin zipper)
   • wider intercellular space
   • Hemidesmosomes: half of desmo, anchor keratin-containing filaments to underlying basement membrane
3. permits passage of ions and small molecules to diffuse freely between cells
   - reduce resistance to passage of electric current
   - 2 Connexons in each channel- hexonally packed annular units, cylindrical, dumbbell-shaped, made of 6 connexins

Question 23

Lateral Interdigitating

Answer 23

increase surface area, engaged in fluid and electrolyte transport

Question 24

Basement membrane

• define
• consists of
• zones
• function

-structures for attachment to connective tiss

Answer 24

• thin supporting layer bet epithelium and underlying connective tissue
• type IV collagen, laminin, proteoglycans, entactin & fibronectin
• lamina lucida and densa
  
  • lamina propria-the connective tiss layer of mucous membrane.
• support epithelium, passive molecular sieve or ultrafilter, repair tissue, compartmentalization
• reticular fibers underlies basal lamina
• Anchoring fibrils, fibrilin microfibrils, discrete projects of the lamina dense

Question 25

Classifying Exocrine glands

Answer 25

1. Duct arrangement:
   - Simple-unbranched
   - Compound-branched
2. Shape of Secretory units:
   - tubular
   - alveolar or acinar
   - tubuloalveolar
   - saccular
3. Type of secretion
   - Serous
   - Mucous
   - Mixed: (bulk-mucous glands, serous demilunes)
4. Secretory Mechanism
   - merocrine
   - holocrine
   - apopcrine

Question 26

Simple Exocrine Glands

Answer 26

• Simple tubular: straight tubules, (-) duc,
• Simple coiled tubular: Coiled:
• Simple branched tubular: bifurcate w/ short
• Simple acinar: bulbous or bottle-shaped

Question 27

Compound Exocrine Glands

Answer 27

• Compound tubular: Tubules more or less coiled
• Compound acinar: bulbous, pear-shaped terminals
• Compound tubuloacinar: short tubules, have a number of acini along their sides and blind end

Question 28

Example of Unicellular glands

Answer 28

Goblet cells, surface lining, glands of intestines, and respiratory tract

Question 29

Derivatives of Ectoderm

Answer 29

1. Surface
   - epidermis, hair, nails, cutaneous, mammary glands
   - ant pit glands
   - enamel of teeth
   - internal ear
   - corneal epithelium, lens of eye
2. Neuroectoderm
   - neural crest: cranial/sensory gang & nerves, adrenal medulla, melanocytes, pharyngeal arch cartilages, head mesenchyme, Schwann cells
   - neural tube: CNS, retina, pineal body, post pit gland

Question 30

Mesoderm derivatives

Answer 30

• muscles of trunk and skeleton except skull
• dermis of skin
• connective tissue
• skull, dentin

Epithelium

• urogenital system including gonads, ducts, and accessory glands
• connective tissue and muscle of viscera and limbs

Mesothelium
-serous membranes of pleura, pericardium, peritoneum

Endothelium

• blood and lymph cells
• cardiovascular and lymphatic systems
• spleen

Question 31

Derivatives of Endoderm

Answer 31

Respiratory

• trachea
• bronchi
• lungs

Alimentary canal
-GI tract

Extramural digestive gland

• liver
• pancreas
• urachus
• pharynx

-thyroid gland

Auditory tubes

• tympanic cavity
• pharyngotympanic tube
• tonsils
• parathyroid glands

Question 32

Microvili Free surface
(striated border-more highly ordered/uniform-intestines
or brush border-kidney)

Answer 32

-slender, finger-like, cylindrical membrane bound cell processes.
-core of actin filaments in association w/ myosin I, that binds them to plasma memb of microvillus.
-anchored to vilin tip
-supported by Terminal Web underneath, made of spectrin, myosin II, tropomyosin for contractile ability.
-cross-linking bundle of 25-35 actin filaments of
proteins fascin and fimbrin

• 1-2 um long, 80-90 nm diameter
• glycocalyx-delicate branching filaments along luminal surface; terminal oligosaccharides of integral membrane proteins
• increase digestive and absorptive effieciency of epithelium

Question 33

Stereocilia Free Surface

Answer 33

• tuft of long, slender processes
• nonmotile
• core bundles of actin microfilament, cross-linked by fimbrin.
• anchors to plasma membrane of stereocilia by erzin
• stem cross-bridging of alpha-actinin
• Function: -limited to epididymis, absorption
  - ear hair cells, sensory

Question 34

Kinocilia/Cillia Free surface

Answer 34

-specialized for transport of fluid or mucus along epithelial surfaces
-axoneme-core complex of longitudinal microtubules
-center: 2 single microtubules
-periphery: 9 doublet microtubules
(in one doublet, cilary dynein is attached on A-microtubule then connects to B-microtubule of adjacent doublet, then bound by nexin-uses ATP)
-base: basal body of nine short microtubule triplets
-7-10 um length, 0.2 cm diameter

Question 35

Flagella Free Surface

Answer 35

• similar to cilia

- 15-200 um