Intro to Histology

Question 1

What is histology?

Answer 1

microanatomy

Question 2

What is histopathology?

Answer 2

The study of changes in the microscopic anatomy, caused by a disease

Question 3

What must you use when handling formalin?

Answer 3

GLOVES

Question 4

What ratio do you use when you are preserving a sample?

Answer 4

1:10 ratio of sample to solution

Question 5

What does fixation of a sample do?

Answer 5

It hardens and preserves tissue
Some tissue shrinkage occurs

Question 6

What do you use to fixate a sample?

Answer 6

Formalin

Question 7

What are the typical histology preparation steps? (6 steps)

Answer 7

Take sample
Fixation
Selection + trimming
Processing + embedding
Sectioning thin slices
Staining to make tissue structures visible

Question 8

What does selection and trimming include during histology preparation?

Answer 8

Choose your orientation and cut surface

Question 9

What does processing and embedding include during histology prep?

Answer 9

Replacing water with a solid medium e.g paraffin wax or resin

Question 10

What solid mediums could you use during the processing and embedding step of histology prep?

Answer 10

Paraffin wax or resin - they replace the water

Question 11

What is the standard stain?

Answer 11

Haematoxylin and Eosin (H&E)

Question 12

Describe the dye Haematoxylin:

Answer 12

it is purple/blue and can be considered a BASIC dye therefore it binds to acids e.g. nucleic acids
IT WILL STAIN THE NUCLEI BLUE

Question 13

Describe the dye Eosin:

Answer 13

it is pink/red and is an acidic dye
and thus it binds to bases, most proteins in the cytoplasm are basic

Question 14

What are immunohistochemical stains and what do they do?

Answer 14

They use antibodies to bind to a tissue-specific substance and there is a second labelled antibody to bind to first

Question 15

What labels can be used to attach to the second antibody when using immunohistochemical stains?

Answer 15

Coloured dye or a fluorescent marker

Question 16

What are the 4 tissue types of the body?

Answer 16

epithelium, connective, muscle, nervous tissue

Question 17

What does all epithelium tissue rest on?

Answer 17

Basement membrane

Question 18

Why do epithelial cells rely in diffusion for nutrition?

Answer 18

Because the blood and lymph vessels do not penetrate the basement membrane in which the epithelial cells rest on.

Question 19

What does the basement membrane act as?

Answer 19

a selective barrier

Question 20

What two major forms does the epithelium exist in?

Answer 20

surface and glandular

Question 21

What is surface epithelium?

Answer 21

Sheets of aggregated cells of similar type, covers all EXTERNAL surfaces and lines all INTERNAL surfaces

Question 22

What is glandular epithelium?

Answer 22

Results from proliferation of surface epithelial cells into underlying tissue and forms secretory cells of endocrine and exocrine glands

Question 23

What are the three types of surface epithelium?

Answer 23

simple, stratified, pseudostratified

Question 24

What are the three types of simple surface epithelium?

Answer 24

Squamous, cuboidal, columnar

Question 25

What are the four types of stratified surface epithelium?

Answer 25

Squamous, cuboidal, columnar, transitional

Question 26

What is simple surface epithelium?

Answer 26

single layer of cells on basement membrane

Question 27

what is stratified surface epithelium?

Answer 27

2 or more layers of cells

Question 28

What is pseudostratified surface epithelium?

Answer 28

appearance of layers but all of the cells are touching the basement membrane, however not every cell is reaching the surface

Question 29

Function of simple surface epithelium?

Answer 29

As thin barrier e.g. lining of blood vessels, exchange of nutrients

Question 30

Function of stratified surface epithelium?

Answer 30

Strong resistance to mechanical stress and forces. Increased strength by adding more cells. In physical strength and wear e.g. skin

Question 31

Describe squamous shape of cells?

Answer 31

scale-like, flat wide cells with greater width than height

Question 32

Describe cuboidal shape cells?

Answer 32

Cube-shaped, similar height and width

Question 33

Describe columnar shaped cells?

Answer 33

Height greater than width

Question 34

Describe transitional shaped cells?

Answer 34

SPECIAL FORM when epithelium is stretched the cells look squamous when epithelium relaxed the cells look cuboidal

Question 35

When are transitional shaped cells useful? In which organ?

Answer 35

For organs that can stretch large amounts. In the bladder (assuming the walls of the bladder)

Question 36

What extra features do epithelia have?

Answer 36

microvilli, cilia, cellular junctions

Question 37

microvilli useful for?

Answer 37

absorption in intestine

Question 38

cilia useful for?

Answer 38

wafting mucus in airways

Question 39

cellular junctions useful for?

Answer 39

for tight attachments between skin cells. to hold the epithelium cells together so that they are less likely to drop off

Question 40

What happens when epithelium cells reach the surface of the skin?

Answer 40

they lose the cellular junction and can fall off

Question 41

cilia are...

Answer 41

motile

Question 42

SQUAMOUS: give use for a single layer of them and for more than one layer of them.

Answer 42

single: diffusion + filtration >1: protection

Question 43

CUBOIDAL/COLUMNAR: give use for a single layer of them and for more than one layer of them.

Answer 43

single: secretion + absorption (ciliated types propel mucus or reproductive cells) >1: protection

Question 44

TRANSITIONAL: give use for more than one layer of them.

Answer 44

Protection; stretching to accommodate distension of urinary structures

Question 45

What is connective tissue derived from?

Answer 45

mesoderm

Question 46

What does connective tissue form and where is it formed?

Answer 46

It forms a matrix beneath the epithelium

Question 47

What is the mesoderm?

Answer 47

a layer of tissue inside the embryo during embryonic development

Question 48

meaning of matrix

Answer 48

a network

Question 49

what does the connective tissue matrix that forms beneath the epithelium help with?

Answer 49

physically supporting and holding up the epithelium

Question 50

What is the difference between the epithelium and connective tissue in relation to number of cells:

Answer 50

connective tissue has relatively few cells unlike the epithelium

Question 51

what is connective tissue mainly made up of?

Answer 51

extracellular matrix

Question 52

Name two 'things' that are found within the extracellular matrix:

Answer 52

Protein fibres Ground substance

Question 53

What is the connective tissue a medium for?

Answer 53

exchange of nutrients and waste

Question 54

2 functions of the connective tissue:

Answer 54

provide structural support to other tissue mediate the exchange of nutrients and waste

Question 55

What are protein fibres mainly made up of?

Answer 55

collagen

Question 56

What properties does collagen give protein fibres?

Answer 56

great tensile strength

Question 57

What gives connective tissue its strength?

Answer 57

The long protein fibres which are mainly made from collagen

Question 58

What two fibres make up connective tissue?

Answer 58

collagen and elastic fibres

Question 59

What do the elastic fibres allow?

Answer 59

stretch and elasticity

Question 60

What are the elastic fibres composed of?

Answer 60

elastin

Question 61

What is the advantage of elastic/protein fibres for the connective tissue?

Answer 61

strong (due to protein fibres/collagen) but also stretchy tissue that can bounce back

Question 62

under the microscope, what colour can collagen show up as?

Answer 62

black

Question 63

What is ground substance?

Answer 63

gel-like material that is transparent

Question 64

What does ground substance do?

Answer 64

it fills spaces between cells and fibres

Question 65

How many different sub-types of collagen fibres are there?

Answer 65

five

Question 66

What % of collagen fibres are type 1?

Answer 66

90%

Question 67

What do the collagen fibres do?

Answer 67

add structural integrity to our tissue

Question 68

What is ground substance made up of?

Answer 68

made up of many large molecules called glycosaminoglycans GAGS

Question 69

What does GAGS stand for?

Answer 69

glycosaminoglycans

Question 70

Describe GAGS flexibility:

Answer 70

inflexible

Question 71

Describe GAGS attraction to water:

Answer 71

very hydrophilic

Question 72

What are they called when multiple GAGS are linked up?

Answer 72

proteoglycans

Question 73

90% of extracellular matrix is what?

Answer 73

water

Question 74

What are GAGS good at binding to?

Answer 74

water

Question 75

What are GAGS very good at resisting and give two reasons why?

Answer 75

Good at resisting compressive forces due to its high water content and because they are inflexible. (think, pushing water out of syringe easy, but if you cover the end of the syringe, impossible to push because water is very good at resisting compressive forces and because GAGS absorb a lot of water, like sponge, they too are good at resisting compressive forces)

Question 76

What does the ground substance facilitate?

Answer 76

movement of cells (macrophages, immune cells) and diffusion of molecules e.g. oxygen

Question 77

Name four types of cells that around found in the connective tissue:

Answer 77

fibroblasts adipocytes immune cells other specialised cells

Question 78

Firboblasts found throughout:

Answer 78

most tissues in body

Question 79

what are adipocytes?

Answer 79

fat cells

Question 80

name three immune cells:

Answer 80

macrophages mast cells plasma cells

Question 81

immune cells go around the... looking for foreign etc.

Answer 81

extracellular matrix

Question 82

give 4 example of the other specialised cells that could be found in the connective tissue:

Answer 82

osteocytes, osteoblasts, chrondocytes, chrondoblasts

Question 83

osteo =

Answer 83

bone

Question 84

chrondo =

Answer 84

cartilage

Question 85

What are fibroblasts?

Answer 85

the least specialised cells, they secrete collagen and ground substance