Chapter 1 (reading)

Question 1

the scientific study of microscopic structures of tissues and organs of the body

Answer 1

histology

Question 2

What is the first step in preparation of a tissue or organ sample?

Answer 2

fixation to preserve the tissue for subsequent treatments

Question 3

What is the most commonly used fixative?

Answer 3

formalin: 37% aqueous solution of formaldehyde
-combined with other chemicals and buffers

Question 4

Formaldehyde preserves the general structure of the cell and extracellular components by reacting with:

Answer 4

amino groups of proteins (cross-linked lysine residues)

Question 5

Why is formaldehyde a poor fixative of cell membranes?

Answer 5

it does not react with lipids

Question 6

What is the second step of tissue preparation?

Answer 6

embedding in paraffin to permit sectioning

Question 7

Preparing a specimen for examination requires its infiltration with an embedding medium that allows it to be:

Answer 7

thinly sliced

Question 8

After fixation, the specimen is _____________and _________________ in a series of alcohol solutions to remove water.

Answer 8

washed and dehyrdated

Question 9

What is function of clearing after dehydration of the tissue specimen?

Answer 9

organic solvents such as xylol or toluol remove the alcohol before infiltration of the specimen with melted paraffin

Question 10

What is a microtome?

Answer 10

a specially designed slicing machine to cut the paraffin

Question 11

a solution that hardens into a permanent mount that keeps the specimen attached to the glass and prevents deterioration of the specimen over time

Answer 11

mounting medium

Question 12

What has to happen before the tissue specimen are stained?

Answer 12

the paraffin must be dissolved out with xylol or toluol and the slide must be rehydrated through a series of descending alcohol concentrations

Question 13

The routine use of ____________as a fixative for electron microscopy is the primary reason for the excellent preservation of membranes in electron micrographs?

Answer 13

osmium tetroxide

Question 14

the process in which radioactively tagged precursors of the molecule are incorporated by cells and tissues before fixation

Answer 14

autoradiography

Question 15

What are the large macromolecular complexes that remain after fixation?

Answer 15

-nucleoproteins
-intracellular cytoskeletal proteins
-extracellular proteins
-membrane phospholipid-protein (carbohydrate) complexes

Question 16

What are some examples of large molecules lost during routine fixation in aqueous fixatives?

Answer 16

glycogen, proteoglycans, and glycosaminoglycans

Question 17

an acidic dye that carries a negative charge

Answer 17

eosin (NA+dye-)

Question 18

carries a net positive charge on its colored portion

Answer 18

basic dye (dye+Cl-)basic

Question 19

basic dyes react with ____________components of cells and tissue

Answer 19

anionic

Question 20

What are the anionic components ?

Answer 20

-phosphate groups of nucleic acids
-sulfate groups of glycosaminoglycans
-carboxyl groups of proteins

Question 21

the ability of anionic groups to react with a basic dye is called what?

Answer 21

basophilia

Question 22

-an intermediate link between the tissue component and the dye
-causes the stain to resemble a basic dye

Answer 22

mordant

Question 23

the reaction of cationic groups with an acidic dye is called what?

Answer 23

acidophilia

Question 24

What three acidic dyes are used in the Mallory staining technique?

Answer 24

aniline blue, acid fuchsin, and orange G

Question 25

the distance by which two objects must be separated to be seen as two objects

Answer 25

resolution

Question 26

what is the function of the light source?

Answer 26

illumination of the specimen

Question 27

what is the function of the condenser lens?

Answer 27

to focus the beam of light at the level of the specimen

Question 28

what is the function of the objective lens?

Answer 28

to gather the light that has passed through the specimen

Question 29

a defect caused by an error in the preparation process

Answer 29

artifact

Question 30

what is the equation for resolution?

Answer 30

d= λ/NA objective + NA condenser