900 Histo Epithelium and Glands Flashcards by Danielle Hayes

What are the 8 types of epithelium?

Simple
       Squamous
       Cuboidal
       Columnar 
       Pseudostratified

Stratified
   Squamous
      - Non-keratinized
      - Keratinized 
   Cuboidal
   Columnar
   Transitional

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What germ layers is the epithelium found?

ectoderm, mesoderm, endoderm

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What are the 5 functions of the epithelia?

protection, transcellular transport, secretion, absorption, selective permeability, detection of sensation

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What kind of transcellular transport does the epithelia participate in?

Vesicle-mediated transport of IGA and other molecules
Carrier protein-mediated transport
e.g. amino acids and glucose across intestinal epithelia
Diffusion of oxygen and carbon dioxide
e.g. across lung alveoli and capillaries

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How does the epithelia function in secretion?

via exocytosis (e.g. hormones, mucus, proteins)

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How does the epithelia function in absorption?

by endocytosis (pinocytosis) e.g. proximal convoluted tubules of the kidneys

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What kind of selective permeability does epithelia typically participate in.

tight junctions

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What are some example of epithelia functioning in detection of sensations?

taste buds, retina of eye and specialized hair cells in the ear

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What does the epithelium line?

cover all body surface, all body cavities, lines all blood vessels and lympathic vessels

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What does simple mean?

one cell layer

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What does stratified mean?

more than one cell layer

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Stratified squamous epithelial can be further subdivided into what?

nonkeratinized and keratinized

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How can a cell be pseudostratified?

All cells rest on basal lamina, but not all reach the lumen; appears ‘falsely stratified’.Though comprising only a single layer of cells, has its cell nuclei positioned in a manner suggestive of stratified epithelia

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What are transitional cells?

dome-shaped when relaxed and flattened when stretched

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What is located here:
Lining: pulmonary alveoli, loop of Henle, parietal layer of Bowman’s capsule, inner and middle ear, blood and lymphatic vessels (endothelium); pericardial, pleural and peritoneal cavities (mesothelium)

Simple squamos

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What is located here:

Distal tubule in kidney, ducts of some glands, surface of ovary

Simple cuboidal

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What is located here:
Lining: oviducts, ductuli efferentes of testis, uterus, small bronchi, much of digestive tract, gallbladder and excretory ducts in some glands

simple columnar

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What is located here:
Lining: most of trachea, primary bronchi, epididymis and ductus deferens, auditory tube, part of tympanic cavity, nasal cavity, lacrimal sac, male urethra, and large excretory duct

Pseudostratified ciliated columnar with goblet cells

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What is located here:

mouth, epiglottis, esophagus, vocal folds, vagina

stratified squamos nonkeratinized

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What is function of stratified squamos

protection

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What is function of transitional stratified

protection, distensible

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What is the function of stratified cuboidal

absorption, secretion

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What is function of stratified columnar

secretion, absorption, protection

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What is the function of simple squamos epithelial?

Limiting membrane, fluid transport, gaseous exchange, lubrication, reducing friction, lining membrane

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What is the function of simple cuboidal epithelial?

Secretion, absorption, protection

What is the function of simple columnar eptihelial?

Transportation, Secretion, absorption, protection

What is the function of pseudostratified ciliated columnar with goblet cells epithelial?

Secretion, absorption, protection, lubrication, transportation

What is the function of the stratified squamos nonkeritinized epithelium?

protection, secretion

What is the function of the stratified squamos keratinizd eptihelial?

protection

What is the function of transitional epithelial?

protection, distensible

What is the function of stratified cuboidal epithelial?

absorption, secretion

What is the function of stratified columnal epithelial?

secretion, absoprtion,protection

What does surfaces does the epithelial cover and is it continuous?

the external and internal surfaces and yes it is continuous

Cells of the epithelial have a direction meaning that they are (blank)

polarized

the cells of the epithelia possess specific (blank) fibers.

intermediate

Epithelial cells are attached by (blank) to form a sheet with little or not intercellular space between cells.

junctional complexes

The epithelial cells are separates from underlying tissues by a (blank)

basement membrane

Are epithelial cells vascular or avascular?

avascular

How do epithelial cells receive nutrition?

via diffusion through basement membrane

What type of cells are endothelium and mesothelium cells?

simple squamos

What does the mesothelium line?

ining of the pericaridal, pleura, & peritoneal cavities

What does the endothelium line?

lines the blood, capillaries, & lymphatic vessels.

What cells have surface modifications and are capable of extensive and rapid regeneration?

epithelial cells

What part of an epithelial cell faces the surface or lumen? what is its function?

apical, | regulation of nutrients and water uptake, regulated secretion

What do epithelial cells rest on?

basement membrane

What is the basal membrane made of?

basement membrane receptors hemidesmosomes plasma membrane infoldings

Celiac sprue results from sensitivity to gluten which is a component of wheat flour. This disease is characterized by a loss of (blank) on the surface epithelium of the small intestine. This abnormality leads to a reduced absorptive capacity with resultant osmotic diarrhea.

microvilli

what is the horizontal network containing mainly actin in the epithelial cell?

terminal web

What is made up of actin +villin; cytoplasmic ends embed in terminal web?

core of microvilli

What are the 5 types of cell surface modifications?

microvilli of striated border, microvilli of brush border, sterocilia (microvilli), cilia, flagella

Where are microvilli of striated borders located?

GI tract, gall bladder

Where are microvilli of brush border located?

Proximal convoluted tubule of kidney, choroid plexus, placenta

Where are stereocilia located (microvilli)?

epididymis, ductus deferens, internal ear

Where are cilia located?

respiratory system, oviduct, uterus, ependyma

Where are flagella located?

spermatozoa

The microtubuls in the cilium have what type of structure?

9 + 2 array of microtbules

Each cilium has a (blank) body from which it grows. Are they taller or shorter than microvilli? What is the function of it?

basal, taller | movement of surface mucus and particulate matter

What does kartagener's syndrome result in?

missing dynein arms of cilia which renders them immobile. | Presents clinically with chronic respiration difficulty (bronchitis, sinustis)

What disorder makes males sterile and can make situs inversus of viscera (switch of organ position to mirrored position)

Kartagener's syndrome (loss of mobility of cilia)

Where is the protein keratin located and what does it do there?

epithelial cells, gives strength, aids desmosome-hemidesmosome association (While desmosomes link two cells together, hemidesmosomes attach one cell to the extracellular matrix.)

(blank) Give Physical Strength to Cells and Tissues

Intermediate Filaments

(blank) Junctions are Characteristic of epithelium

intercellular

Where are junctional complexes found in epithelial cells?

on the apical region

What is the junctional complex comprised of?

``` zonula occludens (ZO) zonula adherens (ZA) macula adherens (MA) ```

What do intercellular junctions function as?

``` Permeability barriers (ZO) Adhesive forces (ZA, MA, hemidesmosomes) Communication channels (gap junctions) ```

What are 5 types of cell junctions

``` ZA ZO MA Hemidesmosomes Gap junctions ```

What does this describe: adjacent cells are bridged by proteins called connexons (made of connexins) forming a hydrophilic channel between two cytoplasms

gap junctions

What does this describe: a large family of ca+2 dependent cell-cell adhesion molecules, are one group of molecules that play a vital role in the anchoring function of intercellular junctions.

cadherins

What is an important mediator of cell-cell adhesion.

extracellular calcium 2+

Formation of intercellular junctions depends upon (Blank). | Adjacent cells each provide (blank) of the junctional structure.

intercellular communication | one-half

What prevents lateral migration of specialized membrane proteins, thus establishing specialized membrane domains?

What mediates folding of epithelial sheets in embryo?

What is used to identify malignant tumors of epithelial origin?

What are most cells in early embryos coupled with?

gap junctions

What are the 2 types of functional junctions?

tight and gap junctions

What are characteristics of tight junctions and where are they located?

-transmembrane proteins -Ca+ dependent -no cytoskeletal elements -allows paracellular transport GI tract, blood/brain, testis

What are the characteristics of gap junctions and where are they found?

-connexins forming connexons -hydrophilic channel -movement of ions and small molecules -couples cells electronically and metabolically -no cytoskeletal elements Cardiac muscle

What are the three types of mechanical junctions?

Adherens, desmosomes, hemidesmosomes

What are characteristics of adherens?

- anchor to actin microfilaments - cadherin (CAMs) - Ca+ dependent

What are the characteristics of Desmosomes and where are they found?

-anchor to keratin (intermediate) -cadherin (CAMs) -Ca+ dependent -strongest junction Epidermis, oral cavity

What are the characteristics of Hemidesmosomes?

- abrasive surfaces (epidermis) - keratin - integrins (CAMs) - laminin (adhesive glycoprotein in GS)

What are the 2 levels of the basement membrane and which layer is seen by an electron microscope?

basal lamina and reticular lamina. | Basal lamina is seen because it is radiodense

What is the basal lamina made of? | product of epithelium

glycoprotein (laminan and fibronectin) + GAG and type IV collagen

What is the reticular lamina made of? | product of underlying CT

Anchoring plaque and fibrils (type IV and VII collagen) and Type I and III collagen

What is the function of the basement membrane?

Provides attachment of epithelium to connective tissue, selective filtration barrier, embryological function, tissue scaffolding.

Is there a direct supply of blood to the epithelium?

Where do you typically find a fusion of 2 basal laminae produced by an epitheliel cell and endothelial cell layer?

kidney glomerulus Alveoli of lung (due to need of more selective filtration)

What is the most common type of basement membrane arrangement?

basement membrane that binds epithelia and separates it from connective tissue (anchoring fibrils made of collagen type VII)

Where do you find serosa?

mesothelium, CT space w/ blood vessels

What makes up the mucosa?

1. Epithelium w/or w/o glands 2. Basement membrane 3. Lamina Propria 4. Muscularis mucosae

You will find mucosa in spaces that are exposed to (blank)

environment, such as respiratory , GI tract, urinary tract

What is dysplasia?

growth into abnormal patterns

What is metaplasia?

conversion to a normal but different tissue

What is neoplasia?

abnormally fast growth of abnormal cells

Cancerous cells typically lack (blank) junctions

gap

Tumor cells turn over in (blank) days

What is the criteria used for classifying exocrine glands?

``` duct arrangment (acinar/tubular or branched/unbranched or simple/compound) Shape of secretory unit (alveolar (acinar) tubular, tubuloacinar) type of secretion (serous, mucous, mixed) Secretory mechanism (merocrine (eccrine) apocrine, holocrin) ```

What does it mean when a duct is compound?

it is branches off of the main branch with branches off that

What does acinar look like?

like an ET finger

What kind of secretion is holocrine secretion and what is an example of it?

Cell produces and accumulates a secretory product in the cytoplasm-such as sebum in sebacous glands- and then disintegrates to release the secretory material.

What kind of secretion is apocrine secretion?

some of the apical cytopasm is released and pinched off like cotton candy and it doesnt repair itself. ex) mammary glands secrete milk lipids this way

What kind of secretion is merocrine secretion?

Secretory vesicle is exoctyosized, also can do endocytosis. ex) milk protein casein is done this way

All glands are derived from what?

epithelium

What is the most common unicellular exocrine gland?

goblet cell

What is the most common secretory mechanism?

merocrine (eccrine) | e.g. sweat glands

Typical salvary exocrine glands are what?

compound tubuloalveolar

Classification by secretion has functional significance. | Serous secretions are found where and what are some characteristics?

parotid, exocrine portion of pancreas Protein rich / carbohydrate poor End pieces are strongly basophilic due to high rER

Mucous secretions come from what type of cell?

goblet cell

What are mixed secretions and where are they found?

- group of mucous cells capped with a serous cell in the demilune position - Carbohydrate rich - staining process takes away carbs Found: submandibular, portions of sublingual