Epithelium Flashcards Preview

Anatomy and Physiology > Epithelium > Flashcards

Flashcards in Epithelium Deck (44)
Loading flashcards...
1

How often does cancer arise from epithelium?

75% of the tim; MAJORITY

2

Tissues

Group of cells closely associated in structure and function

3

Histology

The study of tissues

4

What are the four major types of tissue?

1. Epithelium
2. Connective
3. Muscle
4. Nervous

5

Where are epithelia located?

They COVER or LINE:
a. free surfaces (skin)
b. lining of open cavities (digestive, respiratory systems)
c. lining of closed cavities (ventral body cavity)
d. lining of blood vessels and heart (parietal pericardium (lines heart WALL) visceral pericardium (lines organ itself))}

6

Epithelial Gland

Skin dips down and make something in it when there is a gland
ex. gland in ear makes ear wax

7

What are the 4 main function of Epithelia?

1. Protection- against bacterial infections, injury, etc.
2. Absorption- ex. lining of digestive tract; absorbs food into blood vessels that takes food in
3. Filtration- ex: renal-kidney; make urine, some goes out, some stays
4. Secretion- ex. glandular epithelium

*Or any COMBO of the 4

8

What are the features of epithelial tissue?

-Tightly packed/little extracellular space
- exists as sheets: tight junctions and desmosomes

9

Apical

Top part of cell; often contain microvilli

10

Basal

Bottom part of cell; always attached to basement membrane

11

Desmosome

Anchoring junction; anchors cells together

12

Tight junction

Keeps in in tact so it doesn't fall apart

13

Microvilli

Highly folded EXTENSIONS of the plasma membrane (it IS the membrane) that increases absorption area; brush border

14

Cilia

-Beat in/out; stroke to push things away
EX: filter (beat out) mucous out of mouth and catch particles while its going up. (move substances over surfaces)
-not part of the membrane; they go through the cell membrane and ANCHOR in the cytoplasm

15

What is the structure of cilia?

Core 9+2 microtubule doublets

Basal body (centriole)= 9 microtubule triplets

16

Flagella

longer projections from basal body in cilia; cell propels itself

17

Goblet cell

Musinagen inside them that will become mucous; not cilia covering where goblet cell is bc once it makes mucous, it pushes it out of cell

18

What does it mean if epithelia doesn't sit on basement membrane?

cancer

19

Polarity of epithelia

cell is different all around

20

Basement membrane

-only epithelia have this
-two layers: basal lamina and reticular lamina

21

Is epithelia vascular or avascular?

Avascular; no blood vessels

22

Basal Lamina

-Thin layer; closest to epithelium (secreted BY epithelium)
-non-cellular adhesive layer
-selective filter of materials from blood
-template for wound repair

23

Reticular lamina

-Below the basal lamina
-Extracellular network of collagen fibers

24

Lamina means...

layer

25

How does food get from connective tissue to epithelia if there are no blood vessels in epithelia?

Simple diffusion through capillaries: Blood vessels in connective tissue ----> epithelium; skin is fed from bottom, up

26

Avascularity

Epithelia:
-No blood vessels
-Nutrients by diffusion
-IS innervated (supplied by nerves)

27

Regeneration

Epithelia:
-High mitotic index; one of highest in body

28

Simple epithelium

One layer of cells; contains all 3 shapes

29

Stratified

multiple layers; may have different shapes but nomenclature (naming) is based upon the cell shape of the free (apical) surface

30

3 epithelium shapes

-squamous; flattened
-cuboidal; height=width
-columnar; height>width