Histology

Question 1

what is pathology

Answer 1

microscopic study of diseased cells and tissues

Question 2

what is histology

Answer 2

microscopic study of normal cells and tissues

Question 3

levels of structural organism

Answer 3

cells, tissues, organs, body systems

Question 4

what is a tissue

Answer 4

a group of similar cells organised into tissues to perform a similar function

Question 5

epithelial tissue

Answer 5

barrier and lining tissue. Outer layer of skin

Question 6

Connective tissue

Answer 6

Structural and functional support. Cartilage, bone and blood

Question 7

Muscle Tissue

Answer 7

Specialised for contraction. Cardiac cells

Question 8

Nervous tissue

Answer 8

Carry information through the body via electrical impulses. Nerves

Question 9

Microscope

Answer 9

Tissue samples are illuminated by a beam of light (light microscope) or electrons (electron microscope)

Question 10

LM

Answer 10

reveal basic cellular structure, 0.2 micro metres. More commonly used for routine histopathology

Question 11

EM

Answer 11

can reveal ultrastructure. 1nm (200 folds greater).

Question 12

Microscopy stages

Answer 12

Specimen collection, fixation, dehydration, embedding, sectioning, staining, viewing

Question 13

Specimen collection

Answer 13

incision or punch biopsy - skin/oral surfaces
Needle biopsy - organs or lumps below the skin. Imaging techniques (x ray, mri) are often used to guide
Endoplasmic - flexible tubes

Question 14

Fixation

Answer 14

preserves the structural arrangement between cells and extracellular components. Terminates all biochemical reactions and so prevents tissue decompostion. Fixatives include formaldehyde and glutar

Question 15

Dehydration

Answer 15

Praffin embedding not compatible with water. water removed from tissue using series of graded alcohols. Water removed gradually to prevent distortion

Question 16

Embedding

Answer 16

Thin tissue section needed. But most tissues are delicate. Tissues must be supported to allow thin sections to be cut. Resins and Paraffin wax used

Question 17

Sectioning

Answer 17

Tissue sections must be thin and flat, ideally a single layer of cells. Tissue sections should be transparent, embedded specimens are sectioned using a microtome, sections approximately

Question 18

Staining

Answer 18

Most cells are colourless and transparent, staining makes cells and their components visible

Question 19

Commonly used staining procedures

Answer 19

Haematoxylin and Eosin (H and E)

Question 20

Describe staing procedure

Answer 20

Haematoxylin is a basic dye which stains acidic structures like nucleic acids blue/purple

Eosin is acidic and stains basic structures (such as cytoplasmic proteins) red or pink

Question 21

Periodic acid-schiff reaction (PAS)

Answer 21

Stains complex carboydrate magenta. Mucins produced by goblet cells, brush borders and basement membranes are all PAS-positive

Question 22

Masson trichrome

Answer 22

Stains conective tissues. Nuclei are other basophilic structures stain blue/purple. Collagen stains green/blue. Cytoplasm, muscle, red blood cells and keratin stain red

Question 23

Immunohistochemistry

Answer 23

Antibodies are required to identify substance of interest. Utilises antibody specificity for antigen. Antiboody conjugated to an indicator conjugated to an indicator (e