Epithelia Flashcards Preview

CTO Quiz 1 > Epithelia > Flashcards

Flashcards in Epithelia Deck (59):
1

Four types of tissue

Epithelium, connective, muscle, nerve

2

General features of epithelia (3)

Tightly packed cells, free surface, basement membrane

3

How do epithelial cells get nutrition?

Diffusion from connective tissue

4

Why are epithelial cells mitotically active?

To replace sloughed or damaged cells on apical surface

5

How frequently do you replace dermal cells

15-30 days

6

Functions of epithelium (5)

Protection, absorption, secretion, sensory reception, contractility (in glands)

7

Apical processes designed to increase surface area

Microvilli

8

Functions of microvilli

Usually absorption, can be secretion or sensation

9

Length of microvilli

0.5-1 micron

10

Internal structure of microvilli

Actin anchored to villin and terminal web

11

Length of cilia

2-10 microns

12

Function of motile cilia

Move materials along surface

13

Locations of motile cilia (4)

Respiratory, middle ear, brain ventricles, uterine tubes

14

Structure of motile cilia

9 doublet + 2 central microtubules, anchored to basal body of 9 triplets

15

Cilia motility mechanism

Dynein move along adjacent MT's (requires ATP)

16

Function of primary cilia

Sensory receptor, molecule transport

17

Structure of primary cilia

9 doublets + 0 central MT's

18

Diseases of cilia (2)

Polycystic kidney disease, Bardet-Biedl Syndrome

19

Flagella structure

Ciliary (9+2) surrounded by mitochondria

20

Stereocilia structure

Long microvilli, not motile

21

Stereocilia locations (2)

Epididymis, inner ear

22

Four types of lateral surface junctions

Tight (occludens), adherent, desmosome, gap

23

Structure of tight junction

Occludin and claudin, "ziplock" of proteins in ring around cell

24

Functions of tight junction (2)

Regulates paracellular pathway, defines domains of plasma membrane

25

"Zona occludens"

Tight junction

26

"Zona adherens"

Adherent junction

27

Structure of adherent junction

Cadherens anchored to actin (terminal web) in ring around cell

28

"Macula adherens"

Desmosome

29

Structure of desmosome

Cadherens and binding proteins attach to intermediate filaments at single point

30

Function of desmosome

Strongest attachment between cells

31

Function of gap junctions

Allows passage of small molecules and ions

32

Structure of gap junctions

Six transmembrane proteins (connexins) form connexon around central pore

33

Composition of basement membrane

Proteoglycans, type 4 collagen, fibronectin, laminin, entactin

34

Functions of basement membrane

Limit growth/invasion, scaffolding, diffusion of nutrients and signals

35

Stain needed to see basement membrane

PAS

36

Attachments from epithelia to basement membrane

Hemidesmosomes and focal adhesions (integrins)

37

Diseases of basement membranes

Blisters! Epidermolysis bullosa, bullous pemphigoid

38

Locations of simple squamous epithelium

Kidneys, endothelium (vessels), organ mesentary

39

Locations of simple cuboidal epithelium

Kidney tubules

40

Locations of simple columnar epithelium

Bronchi, intestines

41

Appearance of pseudostratified columnar

Nuclei at different layers, multiple cell types in simple layer

42

Locations of stratified epithelia (non-keratinized)

Esophagus, vagina

43

Locations of keratinized simple squamous

Surface skin - any dry, abrasive surface

44

Differences keratinized vs non-keratinized

Keratin replaces organelles, presence of nucleus, large amounts of pink-staining keratin

45

Locations of stratified cuboidal epithelia

Sweat ducts

46

Locations of stratified columnar

Transitional only - ie anus (strat squam to simple columnar)

47

Appearance of urothelium

Appears stratified, dome shaped cells, stretches to thin, "squamous" layers

48

Metaplasia

Stressed cells can change type, predisposes to carcinomas

49

"Carcinoma"

Cancer of epithelial cells, not all cancers (sarcomas, myeloma, etc)

50

Exocrine gland

Secretion to surface of epithelium

51

Endocrine gland

Secretion to circulatory system

52

Unicellular gland

Simplest type, ie goblet cell

53

Goblet cells

Unicellular exocrine gland, release mucin to GI and respiratory for lubrication and protection, appears foamy

54

Types of multicellular exocrine glands (8)

Simple tubular, branched tubular, coiled tubular, simple acinar, branched acinar, compound tubular, compound acinar, compound tubuloacinar

55

Merocrine secretion

Vesicles fuse with membrane, exocytosis (most common, usually proteinaceous or watery, ex salivary, GI, sweat)

56

Apocrine secretion

Plasma membrane buds off, contain more lipids (rare, mostly mammary)

57

Holocrine secretion

Cell disintegrates, most oily (ie sebaceous glands)

58

Serous secretions

Proteins, appear blue on H+E (ribosomes) while vesicles are more pink

59

Mucous secretions

Appear foamy unless special stains