Ch 1: Methods Of Histology And Cytology

Question 1

What is Anatomy?

Answer 1

Is a branch dealing with external form and internal organization of plants and animals- 2 branches.

Question 2

What are two types of Anatomy?

Answer 2

Gross Anatomy and Microscopic Anatomy (Histology)

Question 3

What is Histology?

Answer 3

Is a branch of science dealing with microscopic structure and function of plant and animal tissue.

Question 4

What is Cytology?

Answer 4

Is a branch of biology that deals with cell formation, structure, and function.

Question 5

Histology and Cell Theory

Answer 5

Until the discovery of Cell Theory by Schwann and Schneider, Histology did not acquire status of a separate science.

Question 6

What are three components of Cell Theory?

Answer 6

• Cells are potentially independent organisms.
• Plants and animals are aggregations of these living units and their secretions.
• All cells originate from pre-existing cells by cell division.

Question 7

What are the Methods of Direct Observation?

Answer 7

• Exteriorization and Transillumination
• Transparent Chamber
• Cell and Organ Culture

Question 8

What is Exteriorization and Transillumination?

Answer 8

This method is for:
- blood circulation in organs
- secretory properties of pancreatic cells
- ovulation in rat.

Question 9

What is a transparent chamber?

Answer 9

• Growth of Capillaries and nerves
• Emigration of leukocytes
• Development of adipose tissue
• Extension: transplant of ovarian cells in monkey cornea.

Question 10

What is Cell and Organ Culture?

Answer 10

Growth of Fibroblasts, bone primordium.

Question 11

What are three other methods for Direct Observation?

Answer 11

-Mechanical Micromanipulation
-Radiation Probes
- Vital and Supravital Staining

Question 12

What is Mechanical Micromanipulation?

Answer 12

Role of nucleus- microneedles, micropipettes.

Question 13

What are Radiation Probes?

Answer 13

Cell Division

Question 14

What is Vital and Supravital Staining?

Answer 14

Certain dyes and stains selectively stain cells and organelles.

Question 15

What are five different methods of differential centrifugation of homogenized tissues?

Answer 15

1. Homogenate Left at gravity for 20 min.
2. Supernatant from step one centrifuged at 1000 X g for 20 min.
3. Postnuclear Supernatant centrifuged at 20,000 X g for 20 min.
4. Postmitochondrial Supernatant centrifuged at 100,000 X g for 1 hr.
5. Postmicrosomal Supernatant centrifuged at 100,000- 500,000 X g for a few hours.

Question 16

What is the result of Homogenate left at gravity for 20 min?

Answer 16

• Pellet containing broken cells.
• Supernatant

Question 17

What is the result of Supernatant from step one centrifuged at 1000 X g for 20 min?

Answer 17

• Pellet containing nuclei, broken cells and intact cells
• Postnuclear supernatant

Question 18

What is the result of Postnuclear supernatant centrifuged at 20,000 X g for 20 min?

Answer 18

• pellet containing mitochondria, lysosomes, and peroxisomes.
• Postmitochondrial Supernatant

Question 19

What is the result of Postmitochondrial supernatant centrifuged at 100,000 X g for 1 hr?

Answer 19

• pellet containing microsomes (fragments of plasma membranes and smooth and rough endoplasmic reticulum).
• Postmicrosomal supernatant.

Question 20

What is the result of postmicrosomal supernatant centrifuged at 100,000 - 500,000 X g for a few hours?

Answer 20

• pellet containing free ribosomes, viruses, large macromolecules such as proteins.
• Cytosol (soluble cellular components).

Question 21

What are the three different types of preparation and examination of killed tissues?

Answer 21

• Fixation stops dynamics of protoplasm
• Embedding
• Staining

Question 22

What is Fixation stops dynamics of protoplasm?

Answer 22

• Fixatives- neutral formalin (37% formaldehyde solution), osmic acid, mercuric chloride

Question 23

What is embedding?

Answer 23

• Embedding of soft tissue in paraffin, gelatin, celloidin
• Sectioning using microtome

Question 24

What is staining?

Answer 24

• Most common stains- hematoxylin and eosin (H and E).
• Refer to stain chart

Question 25

Properties of Stains- Types of Stains.

Answer 25

• Hematoxylin- Eosin (H & E)
• Phosphotungstic Acid - hematoxylin (PTAH)
• Masson Trichome Blue
• Alan

Question 26

Hematoxylin-Eosin (H and E)

Answer 26

-Nuclei- Blue
- Muscle- Pink
- Collagen - Pink
- Elastic fibers - Pink

Question 27

Phosphotungstic Acid - hematoxylin (PTAH)

Answer 27

• Nuclei- Blue black
• Muscle - Blue black
• Collagen - Colorless-pink
• Elastic fibers - Colorless - pink
• Specific for insoluble carbohydrates (polysaccharides)
  
  • gives a red or magenta (deep purplish) color.

Question 28

Masson Trichrome Blue

Answer 28

• Nuclei- Bluish-red
• Muscle- Red
• Collagen - Blue
• Elastic Fibers - Blue

Question 29

Azan

Answer 29

• Nuclei: Bluish- Red
• Muscle: Red
• Collagen: Blue
• Elastic Fibers: Blue

Question 30

What are the types of Histochemical and Cytochemical Procedures?

Answer 30

-Chemical Procedures
- Physical Procedures

Question 31

Chemical Procedures:

Answer 31

• Lipids: uptake of fat-soluble dyes- black color.
• Carbohydrates: Periodic Acid Schiff (PAS) reaction
  
  • Magenta (deep purplish red) color.
• DNA: Feulgen Reaction- green color.
• Proteins and Enzymes: Biuret Reagent - blue color.

Question 32

Physical Procedures:

Answer 32

• UV and X rays

Question 33

Chemical basis of Histological staining: Amphoteric Properties of Proteins

Answer 33

• proteins behave differently in acidic and basic mediums.

Question 34

Chemical Basis of Histological Staining: Isolectric Point

Answer 34

• pH at which molecules carry no net electrical charge ( they are neural).

Question 35

Chemical Basis of Histological Staining: pH

Answer 35

• pH is the negative log of [H+] concentration.

Question 36

Chemical Basis of Histological Staining: Acids and Bases

Answer 36

• are proton [H+] donors and acceptors respectively.

Question 37

Chemical Basis of Histological Staining: Acidophilic vs. Basophilic dyes