Histology- Epithelial cells Flashcards by Ashley Atkins

How small can a light microscope see?

as small as .2 microns

How well did you know this?

Not at all

Perfectly

2 types of light microscopy and difference

fluorescence- fluorescent probe
confocal- particular plane (can’t see plane above or below, thin almost 2-D image)

How well did you know this?

Not at all

Perfectly

Which type of microscope can view living or dead cells?

light

How well did you know this?

Not at all

Perfectly

Which type of microscope uses tissues that are frozen in liquid nitrogen, coated in gold, and dead?

electron

How well did you know this?

Not at all

Perfectly

4 steps of tissue prep for light microscope?

1.) fixation: chemicals cross-link proteins and inactivate degradation enzymes
2.) dehydration and clearing: with alcohol solutions
3.) infiltration and embedding- waxxed and hardened
4.) trimming: sliced thin, transparent

loaded with dye to improve visualization (staining)

How well did you know this?

Not at all

Perfectly

What is it called when cells are stained with fluorescent antibodies that bind to a very specific molecular structure?

immunohistochemistry

How well did you know this?

Not at all

Perfectly

Which 2 dyes are usually done together in light microscopy and what colors are they? Basophilic or acidophilic?

hematoxylin-dark blue- basophilic
eosin-pink-acidophilic

How well did you know this?

Not at all

Perfectly

What stain is great at showing glycogen and glycoproteins, as well as cytosol, mucous, and some ECM?

PAS- periodic acid-Schiff stain

How well did you know this?

Not at all

Perfectly

Which stain is used to see proteins and+ charged molecules?

eosin

How well did you know this?

Not at all

Perfectly

Which stain is used to see DNA, - charged molecules and nuclei?

hematoxylin

How well did you know this?

Not at all

Perfectly

Trichrome stains which areas what color?

conn. tissue=blue
nuclei=dark red/purple
cytoplasm=red/pink

How well did you know this?

Not at all

Perfectly

Functions of epithelial cells?

protection, transport, secretion

How well did you know this?

Not at all

Perfectly

Is epithelium vascular?

How well did you know this?

Not at all

Perfectly

Simple squamous epi. location and function?

lungs, heart, blood vessels, lymph vessels
diffusion, filtration, secretion

EXCHANGE EPITHELIUM

How well did you know this?

Not at all

Perfectly

Simple cuboidal epi. location and function?

ducts, secretory portions of small glands, kidney
secretes, absorbs

TRANSPORT EPITHELIUM

How well did you know this?

Not at all

Perfectly

Simple columnar epithelium?

ciliated tissues, bronchioles, uterine tubes, microvili

absorbs, secretes mucous and enzymes

CILIA= MOTILITY
MICROVILI=increase surface area

How well did you know this?

Not at all

Perfectly

Difference between simple and stratefied?

simple=1 layer
strat= more than 1

How well did you know this?

Not at all

Perfectly

Pseudostratified columnar epi. location? function?

ciliated, bronchi, trachea, resp. tract
secretes mucous

How well did you know this?

Not at all

Perfectly

Stratified squamous epi, location, function?

esophagus, mouth, vagina, SKIN

protects against abraision

How well did you know this?

Not at all

Perfectly

Transitional epi. Location? function?

bladder, urethra, ureters

stretch of urinary organs

CHEMICAL PROTECTION from urine

How well did you know this?

Not at all

Perfectly

Function:
1.) actin
2.) int. filaments
3.) microtubules

1.) shape, motility (actors have nice shape and move on stage)
2.) structural “strength” (Des is an int. student filled with strength and doing K)
3.) polarity, cell division, cilia (microdick could cause polarity and division in a relationship)

How well did you know this?

Not at all

Perfectly

What kind of conn. tissue are desmin and keratin?

int. filaments

How well did you know this?

Not at all

Perfectly

Tight junctions
1.) location
2.) functions

1.) apical aspect of almost ALL epithelial cells. gut, brain, skin, resp. tract. CLOSEST to lumen
2.) barrier, regulate movement, est. polarity, direct memb. proteins

How well did you know this?

Not at all

Perfectly

Most common proteins in tight junctions?

Claudins (small molecules)
Occludin
junctional adhesion molecules (JAM) (permeability)
ZO-proteins (interaction)

(These guys are TIGHT but Claud, Occy and JAM are all trans. But their friend ZO, says NO, and is still in the closet with his skeletons, but introduces them to his skeletons)

How well did you know this?

Not at all

Perfectly

What are found immediately below TJs?

adherens junction In order to stay TIGHT, junctions must have adherens!

Adheren key proteins

Cadherin and catenin (beta-catenin=signal OR connect with cadherin) We must adhere to the rules. Cad is trans and has an cat that must stay inside who likes fish skeletons.

Why is regulation of adherens via cadherin, beta-cadherin and catenin important in regulating would healing?

Can send signals for more cadherin to be made to bridge the gap between epithelial cells. You can lose outer connection (cadherins) but catenins will go signal for new cells and cell division.

Which junctions circle the entire apical aspect of a columnar or cuboidal epi. cell? Which attaches to certain spots only?

Adheren and tight Desmosomes

Which provides more structural stability to the cell? Des or Ad?

Desmosomes

Which type of filaments do desmosomes connect? Example?

intracellular intermediate filaments. Keratin

Adherens and desmosomes both have what kind of "linking" protein? Hemidesmosome has which kind?

claudin-like integrin

Which linking protein binds to a component of the basement membrane known as laminin? And DOES NOT bind to adjacent cell

Integrin Integrin and laminin are linked!

Do hemidesmosomes have important intracellular signaling functions? Tight? Adherin? Desmosomes?

No, yes, yes , yes

What do hemidesmosomes link to?

intracellular intermediate filaments

What are examples of columnar epithelial cells that possess motile cilia?

uterine tubes respiratory epithelium

What structure do cilia have?

9 + 2 (9 microtubules (axoneme) with a central doublet)

Almost all cells have one primary ______

cilia. Non-motile cilia, 9 mt structures but no central doublet. very long (much longer than mv)

When is the primary cilia very important?

development of embryo, sensing fluid movements, sensing growth factors

What does connective tissue proper include?

loose and dense conn. tiss

Which has more collagen, dense irregular or loose conn, tiss? Which has more ground substance? More cells?

dense irregular, loose, loose

Difference in collagen between reg./irreg. conn tiss?

regular has collagen oriented in one particular direction. irreg. is random dispersion

What is collagen synthesized by?

fibroblasts

Function of Type I collagen? Location?

resists tension, multiple triple helices bound together to form fibrils, and fibrils are organized to form fibre. Bone and dense CT

Function of Type II collagen? Location?

resists pressure and absorbs shock cartilage

Function of Type III collagen? Location?

reticular fibers, loose conn. tissue.

Type I, II, III collagens are known as what?

fibrillar collagens

Where does type IV collagen form?

basement membrane that connects epithelial and conn. tiss. layers cross-linked "net" with laminin and proteoglycans

2 major components of ground substance?

multi-adhesive glycoproteins proteoglycans

3 part structure of proteoglycans?

1.) polymer of hyaluronic acid (GAG) 2.) linking proteins attached to the hyl. acid polymer 3.) shorter GAG chains attached to linking proteins

What is the link between collagens and glycoproteins?

proteoglycans

Are proteoglycans highly hydrated? Why?

Yes, -OH groups of the carbs of GAGs

Proteoglycans can store ________

growth factors

Apical layers are made of?

keratin

What protein helps compact keratin and attract water, aiding in skin moisturization?

filaggrin FILL A GRIN with moisture and keratin

What junctions are modified when we age? How?

loss of hemidesmosomes mod of desmosomes TIGHT junctions remain Result: Net result – the “outside” surface of the skin is flattened layers of dead “bags” of keratin and filaggrin linked by tight junctions

What brings nutrients and exchanges gases and wastes?

Capillary loops extending from papillary dermis, in the dermal layer

Where is dermal vasculature found?

dermal layer

What condition has itchy papules and plaques on face and scalp, elbows, knees, wrists, and worsens in response to allergen exposure? What's happening ?

atopic dermatitis, due to subtle abnormalities in filaggrin impair ability of apical strata to retain moisture. Tight junctions become more permeable

Sequence of events for atopic dermatitis?

Impaired skin barrier--> repeated introduction of antigens to immune cells that reside in the epidermis and the dermis --> recruitment of other, particular immune cells into the dermis and epidermis from the blood stream --> a specific type of inflammation (type 2) that causes excessive histamine release into the skin --> chronic swelling and itch with further antigen exposure

What kind of structure is the intestinal mucosa made from? Function?

simple columnar epithelium with prominent apical microvili. Absorption of nutrients

Goblet cells do what?

secrete mucous

What is the bed of highly vascularized loose conn. tiss.? What does it do?

lamina propria absorption of nutrients and water from across the epi. cell into blood.

Which layer are immune cells present?

lamina propria

What are the finger-like projections of epi. and lamina propria, in the intestines?

villus

In the intestinal mucose, there are 2 routes through the epithelium: Which is BETWEEN adjacent enterocytes and what type of junction regulates it? Which is THROUGH enterocytes, across cell membrane and regulated by what?

paracellular, tight junctions transcellular, membrane proteins

What is the component in gluten that celiacs have an immune response to?

gliadin

Paracellular route that may allow gliadin into the lamina propria, causing Celiac Disease?

paracellular route 1: Gliadin binds to a protein (FYI – chemokine receptor CXCR3)  signaling cascade that causes release of a signalling protein called zonulin  Zonulin release leads to phosphorylation of ZO proteins  disassembly of claudin and occludin proteins at the tight junction  leakage of gliadin into the immune cell-containing lamina propria