Histological Principles

Question 1

Size of human RBC

Answer 1

7.5 microns

Question 2

Light Microscopy (LM)

Answer 2

Light beam passed through specimen and magnified. Used with stains.

Question 3

Electron Microscopy

Answer 3

AKA transmission electron microscopy or TEM

Beam of electrons focused on sample, absorbed and scattered to form image on electron sensitive photographic plate

2D structures

500x magnification

Question 4

Scanning electron micrograph (SEM)

Answer 4

type of electron microscopy for visualization of surfaces (3D structures)

Question 5

Types of histology preparation methods (2)

Answer 5

Smear: swipe of cells across slide. Used to count cells, see dimorphic cells or quick overview

Sectional method: most common. Thin slice of tissue used for examination under microscope

Question 6

Steps of sectional preparation method (5)

Answer 6

Fixation, embedding, sectioning, mounting, staining

Question 7

Fixation

Answer 7

Treatment of tissue in order to prevent deterioration over time. Can also be flash frozen for faster analysis

Question 8

Embedding

Answer 8

Prepare tissue for slicing by encasing it in paraffin, plastic or gel. Dehydrates sample.

Question 9

Sectioning

Answer 9

Block with tissue sliced to ~5micron thickness.

Question 10

Plane of section

Answer 10

Plane at which sample is cut can drastically affect appearance

Question 11

Mounting

Answer 11

Process of adhering tissue section to slide

Question 12

Staining

Answer 12

Gives contrast to enhance visualization

Question 13

Histochemistry

Answer 13

stains involving chemical reaction

Question 14

Basic stains

Answer 14

colour acidic cell components (like nuclei). Good for cell morphology. One of two most common stains

Question 15

Hematoxylin

Answer 15

basic stain. Dark blue or purple

Question 16

Acidic stain

Answer 16

colour basic cell components (like cytoplasm). Good for cell morphology. One of two most common stains

Question 17

Eosin

Answer 17

acidic stain. Light pink or orange

Question 18

Basophillic

Answer 18

cell or tissue components that have affinity for basic stains

Question 19

Acidophillic/Eosinophillic

Answer 19

cell or tissue components that have an affinity for acidic stains

Question 20

Trichrome

Answer 20

colours nuclei black or blue; muscle, blood cells, fibrin are red; collagen and mucin blue

Question 21

periodic acid-schiff (PAS) stain

Answer 21

shows structures rich in carbohydrate macromolecules (like glycogen). Magenta

Question 22

elastic stain

Answer 22

stains specific connective tissue (elastin). Black or brown

Question 23

Silver stain

Answer 23

used to show structural fibers. Black

Question 24

Immunohistochemistry

Answer 24

localization of specific antigens in tissue sections by the use of labeled antibodies. Relies on specific antigen-antibody interactions

Question 25

Four basic tissue types

Answer 25

Epithelial tissue, connective tissue, muscle cells, nervous tissue.