Epithelium and Glands (Histology)

Question 1

define tissues

Answer 1

aggregates of cells organised to perform specific functions, through a distinctive pattern of organisation

Question 2

what are the four types of tissue?

Answer 2

1. epithelium (body surfaces, cavities and glands)
2. connective tissue (support)
3. muscle tissue
4. nerve tissue

Question 3

how do you differentiate between the four different of body tissue types?

Answer 3

morphology: epithelial and connective

function: muscle / nerve tissue

Question 4

what is epithelium derived from?

Answer 4

ectoderm and endoderm (early embryonic layers

Question 5

which parts of body are and arent covered by epithelium?

Answer 5

covers all body surfaces

articular cartilage, tooth enamel and anterior of iris

Question 6

what are the functions of the epi?

Answer 6

1. protection (skin)
2. detection
3. sensation
4. regenerative capacity
5. absorption (intestines)
6. material transport (cilia)
7. gas ex (alveolus)
8. excretion
   9 secretion (glands)

Question 7

describe the surface of the epithelium tissue

Answer 7

have a free surface - top surface is free: apical surface
basal surface: attached

Question 8

describe how epi cells are bound

Answer 8

bound by contiguous sheets - joined by cell to cell junctions

Question 9

how are epi cells renewed?

Answer 9

by mitosis

Question 10

how do epi tissue get nourishment and oxygen?

Answer 10

AVASCULAR
nourishment and O2 derived from underlying connective tissue

Question 11

what is epi tissue supported by? what does this do

Answer 11

BASEMENT MEMBRANE - non cellular protein-polysaccharide rich tissue

separates the epithelial from the connective tissue.

The basement membrane is form of extracellular matrix that underlies all epithelia. It provides structural support to epithelia and forms a mechanical connection between epithelia and underlying connective tissue. The basement membrane also regulates the metabolism, proliferation, survival and differentiation of epithelial cells.

Question 12

what is free surface aka?

Answer 12

apical domain

Question 13

what is difference in simple and stratified epithelial tissue?

Answer 13

simple = one cell layer

stratified = multiple layers

Question 14

how are epi cells named with regards to shape?

Answer 14

squamous: flattened (squeezed)
cuboidal: rectangular
columnar: longer than is wide

Question 15

how do u classify epithelium cells?

Answer 15

1. number of cells
2. cell shape

Question 16

where do you find transitional cells?

Answer 16

lower urinary tract

Question 17

describe the structure of transitional cells?

Answer 17

stratified epithelium cells

appear cuboidal when relaxed and squamous when stretched.

Question 18

whats special about transitional cells? where found?

Answer 18

name and location: transitional epithelium of urinary tract

at the top, the cells look dome shaped - look inflated (aka distend)

why?
when bladder is full, it allows the tissue to distend - the cells become flat.

Question 19

what are pseudostratified cells and where found?

Answer 19

appears stratified but they are actually simple due to location of the nucleus. one cell has nucleus close to membrane, but others are further up - give the illusion of multiple layers

location: mainly found in the larger respiratory airways of the nasal cavity, trachea and bronchi.

Question 20

where do you find pseudostratified cells?

Answer 20

trachea

Question 21

what are endothelium cells?

Answer 21

simple squamous epithelia lining of blood vessels

Question 22

what are endocardium cells?

Answer 22

simple squamous epithelial lining of the ventricles and atria of the heart

Question 23

what are the mesothelium cells?

Answer 23

simple squamous epithelial lining of body cavities

Question 24

give 3 e.gs epithelial cells lack a free surface?

Answer 24

Leydig cells in the testis
Lutein cells of the ovary
Langerhan islets of the pancreas

Question 25

what is the name of epithelial cells that lack a free surface?

Answer 25

epithelioid cells

Question 26

what are the three types of epithelial cells that have projections into free space?

Answer 26

1. microvilli 2. stereocilia 3. cilia

Question 27

what appearance do microvilli give under microscope?

Answer 27

rough appearance

Question 28

how are intestine and kidney microvilli described?

Answer 28

the rough appearance under micro for **intestines: striated border** the rough appearance under micro for **kidney: brush border**

Question 29

what do microvilli and stereocilia both have inside them?

Answer 29

actin filaments

Question 30

where do u find stereocilia?

Answer 30

epididymis - help with sperm maturation inner ear - help convert soundwaves to electric impulse

Question 31

which is longer stereocilia or microvilli?

Answer 31

stereocilia

Question 32

how do u describe cilia? where do you find cilia?

Answer 32

extensions of the apical plasma membrane in a nearly all cells in the body

Question 33

how do you classify cilia and where do u find each different type?

Answer 33

1. motile cilia 2. primary cilia - immotile cilia found in almost every cell. NO active movement, but can passively bend 3. nodal cilia: found in embryo

Question 34

what is the basement membrane made of ? describe the two parts

Answer 34

two components: 1. basal lamina - sheet like ECM in direct contact with epithelial cells 2. reticular lamina - supports the basal lamina and is continous with connective tissue (collaged fibres)

Question 35

what are the two distinct proteins found in the basement membrane/

Answer 35

laminin and fibronectin

Question 36

what is role of laminin and fibronectin ?

Answer 36

associate with collagens, proteoglycans and other proteins -\> ORGANISATION OF THE BASEMENT MEMBRANE

Question 37

what is the function of basement membrane?

Answer 37

1. structural attachment 2. filtration - _e.g. glomerular filtration in the kidneys_ 3. compartmentilisation 4. tissue scaffolding during regen 5. regulation and signaling

Question 38

give two e.g.s of where BM plays a key role?

Answer 38

1. glomerular filtration barrier in the kidneys 2. covers the surface of muscle cells - contributes to maintaining the integrity of the skeletal muscle fibre during contraction

Question 39

disruption of basal lamina-cell muscle relationship gives rise to ?

Answer 39

muscular dystrophies

Question 40

where do glands originate from?

Answer 40

invaginated epi. cells

Question 41

describe the structure of glands / glandular epithelium

Answer 41

- secretory units make up the parenchyma - supported by connective tissue

Question 42

what is the parenchyma?

Answer 42

tissue which conducts the specific function of the organ and usually comprises the bulk of the organ.

Question 43

what does stroma mean?

Answer 43

connective tissue

Question 44

where are gland products produced?

Answer 44

intracellularly

Question 45

what do glands secrete?

Answer 45

mucus, enzymes and hormones

Question 46

what are the different types of exocrine glands?

Answer 46

simple - singular branching branched - few branches compound - multiple branches

Question 47

what is exocrine and endocrine cells? where are products secreted for each?

Answer 47

exocrine: product secretion onto the surface directly / through epithelial ducts connected to the surface endocrine: lack a duct system. products secreted into connective tissue + then blood stream

Question 48

what are the different types of exocrine gland secretion?

Answer 48

1. **merocrine / eccrine secretion**: product is delivered through exocytosis **2. apocrine secretion:** product is secreted via partial loss of the cell apical portion **3. holocrine secretion:** product out by cell apoptosis

Question 49

how are exocrine glands classified?

Answer 49

1. unicellular glands - secretion by a single cell (ie goblet) 2. multicellular glands - more than one cells and can assume different structural organisation

Question 50

what type of secretions do: 1. mucous glands 2. serous glands create?

Answer 50

mucous - viscous serous - watery

Question 51

what are epithelium cells renewed by?

Question 52

draw epithelial cell structure include: - epithelial cells - apical domain - basement membrane - basal domain

Answer 52

Question 53

what is a squamous cell? draw simple and stratified squamous cells

Answer 53

flattened cell

Question 54

what is a cuboidal cell? draw simple and stratified cuboidal cells

Question 55

what is a columnar cell? draw simple and stratified columnar epithelial cells

Answer 55

height \> width

Question 56

name type of epi. cells found here

Answer 56

simple squamous

Question 57

what classification are these cells?

Answer 57

si

Question 58

what type of epi. cells are these?

Answer 58

simple columnar

Question 59

what are epithelium cells called that lack a free surface?

Answer 59

**epitheloid cells**

Question 60

nuclei of cells in glandular cells always face...?

Answer 60

basal membrane

Question 62

what three features are used to classify epithelia?

Answer 62

Shape of surface cells Number of layers of cells Specializations

Question 63

What specializations are found on the apical surface of epithelial cells and their function?

Answer 63

Microvilli - increases the apical surface available for absorption Cilia - motility Keratin - protection and dehydration

Question 64

Are epithelia polarized?

Answer 64

Yes, epithelial cells have distinct apical (top), basal (bottom), and lateral (side) surfaces

Question 65

name for translational cells?

Answer 65

umbrella cells

Question 66

where do you find pseudostratified epithelium cells?

Answer 66

trachea