Intro to histology

Question 1

what is histology?

Answer 1

microscopic study of normal cells and tissues

Question 2

what is pathology?

Answer 2

microscopic study of dieased cells + tissues

Question 3

name the 4 main types of tissue

Answer 3

epithelial. connective, muscle and nervous

Question 4

name the two types of microscopy used in histology and the differences between them

Answer 4

Light:
. basic cellular structure
. lower resolution
. large field of view
Electron
. ultrastructure
. greater resolution,  more detailed

Question 5

name and describe the first step of microscopy

Answer 5

Speciment collection

. incision, needle biopsy, endoscopic biopsy or x-ray/ mri taken

Question 6

name and describe the second step of microscopy

Answer 6

Fixation
. preserve structural arrangement of cell
. stop biochemical reactions
. fixatives- farmaldehyde/glutaraldehyde

Question 7

name and describe the third step of microscopy

Answer 7

dehydration
. paraffin embedding not compatible with water so water must be removed from tissue gradually using alcohol to prevent distortion
. alcohol then replaced with xylene

Question 8

name and describe the fourth step of microscopy

Answer 8

Embedding
. thin section required, tissue can easly be distorted when sectioning so it must be supported to allow it to be cut
. resins/ paraffin eax used
. paraffin not compatible with alcohohl so xylene replaced

Question 9

name and describe the sixth step of microscopy

Answer 9

Staining
. most for LM aq
. not compatible with paraffin, reversal dehydration steps to remove paraffin and replace with water

Question 10

name 4 commonly used staining techniques

Answer 10

H&E, PAS, Masson Trichrome and immunohistochemistry

Question 11

name and describe the fifth step of microscopy

Answer 11

sectioning - tissue sections must be thin/flat (ideally single layer of cells)

• carried out using microtome
• sections look diff depends where they are cut