Lecture 6 Flashcards Preview

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Flashcards in Lecture 6 Deck (32):
1

location of epithelial cell specializations

intercellular surfaces, luminal surfaces, basal surfaces

2

types of specializations at intercellular surfaces

occluding, adhering, and communicating junctions

3

types of specializations at luminal surfaces

cilia, microvilli, stereocilia

4

types of specializations at basal surfaces

basement membrane and hemidesmosomes

5

function of tight junctions

seals neighboring cells together in epithelial sheet to prevent leakage of molecules between them

6

function of adhering junctions

joins an actin bundle in one cell to a similar bundle in a neighboring cell - anchor cystoskeleton and bind epithelial cells together

7

function of desmosome

joins the intermediate filaments in one cell to those in a neighbor

8

function of gap junction

forms channels that allow small water soluble molecules (Ca2+, cAMP, pH) between cells

9

function of hemidesmosome

anchors intermediate filaments in a call to the basal lamina

10

where are tight junctions located

directly below luminal/apical surface

11

types of adhering junctions

zonula adherens (also just called adhering junctions)
desmosomes (macular adherens)

12

location of adhering junctions (zonula adherens)

deep to zonula occludens (tight junction)

13

location of desmosomes (macula adherens)

deeper than zonula adherens

14

where are desmosomes often found

stratified squamous cells

15

function of desmosomes

structural integrity (REMEMBER THESE ARE A TYPE OF ADHERING JUNCTION)

16

composition of desmosomes in three locations

intercellular - desmocollins
transmembrane - desmogleins
plaque - desmoplakin, keratin

17

gap junction location

below junctional complex

18

cell specializations at basal surface

hemidesmosomes and basement membrane

19

hemidesmosome function

anchorage of cytoskeleton at base of cell to basement membrane

20

hemidemosomes contain what kind of filaments

intermediate filaments (tonofilaments or cytokeratins)

21

function of basement membrane (6)

1. physical support
2. cell attachment
3. selective barrier
4. growth, differentiation
5. regeneration
6. special functions ex ultrafiltration in kidney, blood air barrier (lung), tumor metastasis

22

composition of basement membrane (6)

1. type 4 collagen (ONLY IN BM!!!!)
2. laminin (binds collagen to BM)
3. proteoglycans
4. entactin (binds laminin to type 4 collagen)
5. fibronectin (binds integrins of plasma membrane, produced by fibroblasts of the connective tissue)
6. type 7 collagen (binds basal lamina to subjacent collagen)

23

how many microvilli per cell

3000 to increase SA for absorption

24

structure of cilia

central microtubule pair surrounded by 9 doublets inserted into basal body composed of 9 microtubule triplets

25

function of cilia

clean airways, transport ovum

26

how is movement achieved with cilia

longitudinal -- movement of doublets relative to one another, ATPase, active

27

sperm moved by

microtubules, cilia

28

microvilli composition

20-30 actin filaments

29

how is movement achieved with microvilli

contract and elongate, no ATPase

30

stereocilia

misnamed, actually made of actin so really villi

31

where are stereocilia found

male reproductive tract, epididymus

32

movement of stereocilia

not active, no ATPase