Section A: Theory of Staining

OF 4 MSP 2121

SECTION A: THEORY OF STAINING

Question one

Answer the following multiple choice questions. Write only the letter of your choice.

1.1 In negative staining the shapes of structures are disclosed by

a. complete saturation of the section with a basic dye. b. staining the tissue partially with a cationic dye. c. surrounding the structure with the dye. d. gradual removal of the stain with aqueous solvent. e. none of the above (1)

1.2 Covalent bonding is the major reagent-tissue interaction in

a. enzyme histochemistry. b. Gomori silver impregnation. c. Carminic acid stain. d. PAS. e. None of the above (1)

1.3 Essentially hydrophobic bonding contributes to dye-tissue attachment by

a. creating opposite charges between dye and tissue. b. “pushing” hydrophobic groups in aqueous medium together. c. converting the dye to a chromophore d. decreasing the entropy of the system. e. None of the above (1)

1.4 Regressive staining means

a. that the stain is performed from the end. b. the final result is a product of stain removal. c. the method involves dehydration and then rehydration as a final phase d. a method using haematoxylin e. None of the above (1)

1.5 Acid fuchsin is said to be a

a. Cationic stain. b. Anionic stain. c. Amphoteric (both cationic & anionic) stain d. Neutral stain e. None of the above (1)

1.6 Define the following dye terms:

a. dye (1) b. chromophore (1) c. chromogen (1) PAGE 2 OF 4 MSP 2121 1.7 Explain how auxochromes can enhance the colour of dyes. Use naphthalene as your parent compound. (10)

Question two

Answer the following questions as either true (T) or false (F).

2.1 The process by which electrons are stimulated by radiation is resonance. (1) 2.2 Fluorescence is the result of rapid release of radiant energy without prior stabilization of energy. (1) 2.3 Direct dyes are in fact a sub classification of acid dyes. (1) 2.4 Azo dyes have the chromophore –N=N-. (1) 2.5 Fast red B is an example of a diazo compound. (1)

2.6 Match the dye name in column A with the correct classification in column B. (7)

A B a. haematoxylin NITRO b. Alizarin red S ACIDIC c. Sirius red PHTHALOCYANINE d. Picric Acid BASIC e. Alcian blue ANTHRAQUINONE f. methylene blue AZO g. eosin Y THIAZINS

Question three

3.1 List three (3) general rules of dye chemistry. (3)

3.2 Discuss extraneous factors during pre-fixation that could affect staining. (9)

3.3 Fill in the missing word.

“Although it is common practice to use haematoxylin as the source of dye, it is not itself the actual dye. During the preparation of staining solutions, the haematoxylin is converted into ______.” (1)

3.4 Give the name of the stain used to demonstrate the following tissue components:

a. Glycogen (1) b. Iron (1)

Question four

4.1 Outline Wallington’s artifact classification (half marks given) and provide an example of a common artifact in each category. {(8x½=4) + (8) = 12)}

4.2 Match the histological pigment in column A with the diagnostic significance in column B. (8)

A B a. bile ANTHRACOSIS b. melanin MESOTHELIOMA PAGE 3 OF 4 MSP 2121 c. lipofuscin HAEMOLYTIC ANAEMIA d. iron HAEMOCHROMATOSIS e. carbon HAEMOSIDEROSIS f. asbestos DYSTROPHIC CALCIFICATION g. haemosiderin MALIGNANT MELANOMA h. calcification STRESSFUL ILLNESS

4.3 What does restoration involve in museum techniques? (4)

4.4 What staining method is used by museums to stain fetal skeletons? (1)

Question five

5.1 Briefly explain how pH, tonicity and temperature can influence fixation for electron microscopy. (6)

5.2 List six (6) criteria that the ideal embedding medium for electron microscopy must meet. (6)

5.3 By means of a table compare light microscopy and electron microscopy using the following headings: a. Average resolution (2) b. Skill required for sample preparation (2) c. Thickness of preparations (2) d. Surrounding of the preparation (2)

SECTION B: NORMAL HISTOLOGY

Question one

Answer the following multiple choice questions. Write only the letter of your choice.

1.1 The space of Disse is found between the

a. myoepithelial cell and its associated acinus in a salivary gland. b. epithelial cell and hepatocyte in sinusoid. c. lamina propria and lining epithelium of the esophagus. d. leydig cell and spermatid. e. None of the above (1)

1.2 The cells forming the intercalated ducts of a salivary gland are _____ in shape.

a. cuboidal b. low columnar c. columnar d. tall columnar e. None of the above (1) PAGE 4 OF 4 MSP 2121 1.3 The trachealis muscle forms the posterior border of the

a. esophagus. b. colon. c. jejunum. d. trachea. e. fallopian tube. (1)

1.4 Lining epithelial cell of the fourth ventricle of the cerebrum is called a

a. kuppfer cell. b. peg cell. c. mesangial cell. d. ependymal cell. e. None of the above (1)

1.5 Simple squamous epithelial lining is found in all of the following locations except

a. the alveolus. b. the liver sinusoids c. thin portion of the loop of Henle d. the ectocervix e. None of the above (1)

1.6 Outline the layers in the wall of the esophagus. (9)

1.7 What structures are located in the portal triad? (3)

1.8 Outline the histological structure of the adrenal cortex. (9)

Question two

Answer the following questions as either true (T) or false (F).

2.1 In the small intestine the mucosa invaginates between the villi to form the crypts of Lieberkuhn. (1) 2.2 The visceral portion of Bowman’s capsule is lined with a simple squamous epithelium. (1) 2.3 The thyroid follicle is the structural and function building block of the thyroid. (1) 2.4 The pyramidal cell layer is found in the neocortex of the cerebrum. (1) 2.5 Trebecular arteries of the spleen enter the white pulp where they are called peripheral arteries. (1)

2.6 List the tissue components oxygen must diffuse across from alveolar space to blood capillary lumen. (4)

2.7 While examining an H & E section of the prostate you find round eosinophilic bodies. What are these bodies? (5)

EXAM TOTAL [130] PAGE 5 OF 4 MSP 2121