Lab 2 - Intro to histology techniques and epithelial tissue

Question 1

Pancreas endocrine

Answer 1

production of hormones

Question 2

Pancreas endocrine

Question 3

Pancreas exocrine

Answer 3

Production of digestive enzymes = exocrine

Question 4

Pancreas

Answer 4

one of the accessory glands associated with the mammalian gut

produces hormones (endocrine) and digestive enzymes (exocrine). Since these are proteins the cells of the pancreas are specialised for the synthesis and export of massive quantities of protein

Question 5

Pancreas function reflected in their structure

Answer 5

The organelles concerned with protein synthesis( rER) and export (golgi apparatus) are highly developed

Question 6

The pancreas in made up of large numbers of cellular clusters called

Answer 6

acini which are closely packed together and the lumens of these acini lead to intralobular ducts and then interlobular ducts and finally the pancreas duct itself

Question 7

Cytochemical staining method

Answer 7

designed to specifically stain the two types of nucleic acid - DNA and RNA

Question 8

Routine steps in preparing sections for light microscopy

Answer 8

Removal of fresh tissue
Then have removed piece of tissue
Tissue cut to appropriate size
fixation e.g. with formaldehyde
dehydration in increasing concentrations of alcohol
embedding e.g. in paraffin or paraplast
completed paraffin tissue block
Sectioning on a microtome with steel knife
Sections mounted on glass slide and dried
Removal of paraffin with xylene
Seres of graded alcohol (decreasing concentrations)
Staining of mounted sections such as with H and E
Series of graded alcohol (increasing concentrations)
Stained sections in mounting medium under coverslip reading for microscopy

Question 9

4 basic tissue types

Answer 9

epithelium
connective
muscle
nervous

Question 10

Methyl Green (MG) specifically stains

Answer 10

DNA green

Question 11

Pyronin-Y (PY) specifically stains

Answer 11

RNA pink

Question 12

What structures in the pancreatic cells would stain with MG and what would stain with PY?

Answer 12

Nucleus will be stained green from the MG

Nucleous and basal sytoplasm will be stained pink by the PY because of the RNA in the nucleolus and the ribosomes and RER in the cytoplasm

Question 13

Light microscopy

Answer 13

used to look at thin sections of tissues with the objective lens allowing different magnifications

to allow cells and cell structures to be visualiised different stains are used to differentiate between structures

Question 14

Scanning electron microscopy (SEM)

Answer 14

To look at the surface of a cell or structure at high magnification without sectioning it, SEM uses electron beams to create a 3D image

Question 15

Scanning electron microscopy (SEM)

Answer 15

To look at the surface of a cell or structure at high magnification without sectioning it, SEM uses electron beas to create a 3D image

Question 16

Pancreas exocrine

Answer 16

Production of digestive enzymes = exocrine

Question 17

Pancreas

Answer 17

one of the accessory glands associated with the mammalian gut

produces hormones (endocrine) and digestive enzymes (exocrine). Since these are proteins the cells of the pancreas are specialised for the synthesis and export of massive quantities of protein

Question 18

Pancreas function reflected in their structure

Answer 18

The organelles concerned with protein synthesis( rER) and export (golgi apparatus) are highly developed

Question 19

The pancreas in made up of large numbers of cellular clusters called

Answer 19

acini which are closely packed together and the lumens of these acini lead to intralobular ducts and then interlobular ducts and finally the pancreas duct itself

Question 20

Cytochemical staining method

Answer 20

designed to specifically stain the two types of nucleic acid - DNA and RNA

Question 21

Routine steps in preparing sections for light microscopy

Answer 21

Removal of fresh tissue
Then have removed piece of tissue
Tissue cut to appropriate size
fixation e.g. with formaldehyde
dehydration in increasing concentrations of alcohol
embedding e.g. in paraffin or paraplast
completed paraffin tissue block
Sectioning on a microtome with steel knife
Sections mounted on glass slide and dried
Removal of paraffin with xylene
Seres of graded alcohol (decreasing concentrations)
Staining of mounted sections such as with H and E
Series of graded alcohol (increasing concentrations)
Stained sections in mounting medium under coverslip reading for microscopy

Question 22

4 basic tissue types

Answer 22

epithelium
connective
muscle
nervous

Question 23

Methyl Green (MG) specifically stains

Answer 23

DNA green

Question 24

Pyronin-Y (PY) specifically stains

Answer 24

RNA pink

Question 25

What structures in the pancreatic cells would stain with MG and what would stain with PY?

Answer 25

Nucleus will be stained green from the MG Nucleous and basal sytoplasm will be stained pink by the PY because of the RNA in the nucleolus and the ribosomes and RER in the cytoplasm

Question 26

Light microscopy

Answer 26

used to look at thin sections of tissues with the objective lens allowing different magnifications to allow cells and cell structures to be visualiised different stains are used to differentiate between structures

Question 27

Transmission electron microscopy (TEM)

Answer 27

used beams of electrons through the surface of thin sections of tissue to visualise structures at a much higher magnification

Question 28

Scanning electron microscopy (SEM)

Answer 28

To look at the surface of a cell or structure at high magnification without sectioning it, SEM uses electron beams to create a 3D image

Question 29

Microvilli with different microscopes

Answer 29

At LM microvilli can only be seen as a brush border. Either TEM or SEM would provide a clearer view of individual microvili

Question 30

Staining allows us to

Answer 30

highlight key structures within the tissue

Question 31

H&E stands for

Answer 31

Haematoxylin and Eosin

Question 32

H&E

Answer 32

Haemotoxylin is a basic dye that stains acidic structures purple. Eosin is an acidic dye that stains basic structures red/pink e.g. cytoplasm is basic therefore is pink and the nucleus is acidic because of DNA therefore stained purple

Question 33

Aldehyde acid fuschin

Answer 33

Stains elastic tissue purple

Question 34

Alcian green

Answer 34

Stains microvilli green and mucus in goblet cells blue/green

Question 35

Haemtoxylin alum (gills haematoxylin)

Answer 35

stains nucleus of epithelial cell blue

Question 36

Biebrichs scarlet

Answer 36

Stains granules in epithelial cells bright red, also red blood cells and most cell cytoplasm stained red, nuclei red/purple

Question 37

Analine blue + picric acid

Answer 37

stains cytoplasm an orange-red, collagen blue

Question 38

Pentachrome =

Answer 38

``` Aldehyde acid fuschin Alcian green Haemtoxylin alum (gills haematoxylin) Biebrichs scarlet Analine blue + picric acid ```

Question 39

Pentachrom will also stain on top of H&E structures...

Answer 39

also stain elastic tissues, mucous (green with alcian green), epithelial nuclei, cell membrane specialisations such as microvilli and collagen

Question 40

Benefits of LM

Answer 40

Relatively cheap, easy to use, limited magnification Can go into the field easily - benefits to science rather than benefits to just you

Question 41

Benefits and disadvantages of EM

Answer 41

High magnification, able to visualise small organelles and structures very expensive, very large

Question 42

Tight junction

Answer 42

controlling the paracellular pathway, prevents luminal contents passing between cells

Question 43

Zonula adherens

Answer 43

provides structural support and reinforcement between cells

Question 44

Desmosome

Answer 44

Binds epithelial cells together as a tight unit/tissue

Question 45

Hemidesmosome

Answer 45

provide anchoring support for the cell into the basement membrane via its cytoskeleton

Question 46

Antibody against actin in epithelial cell junctions

Answer 46

tight junctions, zonula adherens

Question 47

Antibody against cytokeratin in epithelial cell junctions

Answer 47

desmosomes and hemidesmosomes

Question 48

Microvilli microscopy

Answer 48

apical function = absorption visible at EM and shown as a brush border at LM

Question 49

Nuclei/nucleolus microscopy

Answer 49

BAsal function = cell activity visible at LM and EM

Question 50

Mitochondria microscopy

Answer 50

Apical and basal Function = energy visible at EM

Question 51

Actin microscopy

Answer 51

Apical function = anchor/junction visible at EM

Question 52

Junctions microscopy

Answer 52

Apical function = protection visible at EM

Question 53

RER/golgi microscopy

Answer 53

Apical/basal function = protein synthesis Visible at EM

Question 54

Phase-contrast microscopy

Answer 54

is primarily a means of looking at living cells. It renders transparent objects, which do not absorb light and which cannot be seen with any clarity in bright field microscopy USed bed on single cells or on layers of one cell thick from which refractile structures are absent

Question 55

Phase contrast vs bright field microscopy

Answer 55

Phase contrast is better for cisualising unfixed, unstained tissue, whereas conventional bright field microscopy is best for visualising fixed and stained tissues