Epithelium Flashcards Preview

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Flashcards in Epithelium Deck (68):
1

Basic functional unit of the body

cell

2

A collection of cells and material between cells that perform specialized functions

tissue

3

A structure or mass formed by basic tissues to perform specialized functions

organ

4

A group of organs that work together to perform specialized functions

system

5

Epithelium traits (2)

Covering and lining of surface
Secretion

6

Epithelium is derived from

ALL GERM LAYERS
Ectoderm
Mesoderm
Endoderm

7

Functions of epithelium (7)

-protection
-Transcellular transport (active and passive)
-Secretion
-Absorbtion
-Selective permeability
-Sensory detection
-Contraction (myoepithelial cells)

8

Characteristics of epithelium (3)

-Composed entirely of cells
-Avascular (no blood vessels)
-Polarity (apical, lateral, basal)

9

Physical arrangement of epithelium (3)

1-sheets of tightly bound cells (membrane)
2-Glands (single or group secretory)
3-Non-secretory individiul or small clusters of cells

10

Membrane epithelium arranged:

In sheets to cover body surfaces (inside and outside)

11

3 criteria for epithelial classification

1-Number of layers of cells
2-Shape of cells in surface layer
3-Special modification of epithelial cells

12

Number of layers of cells can be

Simple (1 layer of cells)

Stratified (more than 1 layers of cells)

13

Shape of cells in surface layer

Squamous-flat

Cuboidal-square

Columnar-rectangular

14

Classes of epithelium in sheets with unique characteristics

Transitional epithelium

Pesudostratified columnar epithelium

15

3 specialized modifications of epithelial cells

1-Apical cell membrane
2-Basal cell membrane
3-Cytoplasm

16

Special modification of epithelial cell

Apical cell membrane (3)

-Kinocilia=long, mobile projections-CILIA
-Microvilli=short projections-BRUSH BORDER
-Stereocilia=long, non-mobile projections

17

Special modification of epithelial cell

Basal cell membrane

Basal infoldings=invagination in basal cell membrane

18

Special modification of epithelial cell

cytoplasm

Keratinization=deposition of proteinaceous filaments

19

Psuedostratified columnar epithelium

-simple epithelium
-Variable cell shapes
-All cells attach to basement membrane
-Not all cells reach surface of epithelium
-Common with apical surface modification (cilia or sterocilia)

20

Transitional epithelium

-stratified epithelium
-shape of surface cells variable
-Can stretch without breaking cell to cell attachment

21

Apical, basal, lateral polarity arrangement

Apical- toward lumen if present
Basal-attached to basement membrane
Lateral- on sides of cell that aren't basal or apical

22

Adhesion of epithelial cells to other things via

Junctional complexes or terminal bars

on apical surface of cell

Glycocalyx and microvilli help

23

Types of attachments between epithelial cells (4)

Macula-spot
Zonula-girdle or belt
Occludens-tight seal
Adherens-site of adhesion

24

Desmosome is example of what type of attachement

Macula adherens

25

Some specialized structures in junctional complexes (2)

Gap juntinos

Hemidesmosomes

26

Intercellular bridges

desmosomes

27

Components of basement membrane (2)

1-Basal lamina
2-Lamina relicularis or Lamina fibrorecticularis

28

Basal lamina

Made by epithelial cells
-->lamina lucida
-->lamina densa

29

Lamina relicularis or lamina fibroreticularis is made by

fibroblasts

30

Functions of the basement membrane (3)

-Attachment of epithelium
-Filteration
-Direct cell migration during wound healing

31

Definition of gland

One or more specialized cells that elaborate secretory products (material not related to their ordinary metabolic needs)

32

Glands originate from

Epithelial cells

33

Glands are formed by

Projections of epithelium at a surface of the body into underlying mesoderm (primitive CT)

34

Components of glands (2)

Parenchyma

Stroma

35

Parenchyma of glands

Secretory epithelial cells

Epithelial cells of ducts

36

Stroma of glands

CT matrix and cells
Blood vessels
Nerves

37

To be a gland: 6 criteria

1-presence or absense of a duct
2-Number of secretory cells (exocrine or endocrine)
3-Nature of secretory product of exocrine
4-Mode of release (secretion) of secretory product by cells of exocrine glands
5-Collective shape of groups of secretory cells of exocrine gland
6-Distance endocrine secretory product must travel

38

Gland with a duct

Exocrine gland: ducts transport secretory product to surface

39

Gland without duct

Endocrine gland:releases secretory product into blood vessels or tissue fluid for transport carried to other locations in the body

40

Example of unicellular gland

Goblet cell and APUD cell

41

Example of multicellular gland

Salivary gland and parathyroid gland

42

Nature of secretory product of exocrine gland (4)

-Serous secretion
-Mucous secretion
-Mixed secretion
-Sebaceous secretion

43

Serous secretion product

Watery, rich protein

44

Mucous secretion product

Viscous, slippery, rich in sugar

45

Mixed secretion product

Components of serous and mucuos secretions

46

Sebaceous secretion product

Lipids (oily secretion termed sebum)

47

Mode of secretion of secretory product by exocrine gland (3)

-merocrine
-apocrine
-holocrine

48

Merocrine secretion

Secretory product released from secretory granule with NO loss of cytoplasm

49

Apocrine secretion

Small portion of apical cytoplasm pinched off and released with secretory product

50

Holocrine secretion

Entire cell released with secretory product

51

Collective shape of groups of secretory cells of exocrine gland (3)

Tubular (like test tube)
Acinar (berry shaped with tiny lumen)
Aleveolar (big berry with big lumen)

52

Distance secretory product of endocrine gland can travel (3)

-Autocrine
-Paracrine
-Endocrine

53

Autocrine

Endocrine glands use this

Secretory product directly acts on same cell

54

Paracrine

Endocrine glands use this

Secretory products acts on adjacent cells

55

Endocrine

Endocrine glands use this

Secretory product travels via vasculature to act on distant cells.

56

Exocrine glands can be classified as (2) depending on duct

-Simple-duct is unbranced

-Compound-if duct does branch

57

Lobe vs lobule

Lobules are separated by septums (CT wall) WITHIN the lobe. Lobules hold individual secretory acini.

58

What's commonly found in the infoldings of basal cell membranes?

Elongated mitochondria to allow E to be used in active membrane transport system.

59

What will you find on epithelium that is exposed to extensive frction

Keratin. For protection

60

Classification of epithelium is based on

Morphology (cell layer, shape, special modifications)

61

Name of epithelium is based on

Specific site in the body

62

SSE that lines blood vessels, lymphatic vessels, and heart is

endothelium

63

Glyococalyx

Protective layer of glycoproteins

64

Goblet cells
-Secrete
-derived

Single cell gland
-secrete mucus-->mucinogen (unhydrated precursor of mucus)
-derived from endoderm

65

What composes junctional complex

tight junctions (zonular occludens)
zonular adherens
desmosomes (macula adherens)
gap junctions (nexus)

66

Where can you see mitosis?

Basement membrane

67

Keratohyalin

Small basophilic granules in cytosplasm that are associated with aggregation of keratin filaments.

68

Transtional epithelum appearance is due to

Stretching