A- Answer all the following questions:
1- What are Mercury pigments?
2- Numerate 3 reagent used in dehydration?
4- What are the characters of good clearing agent?
3- Numerate 3 Non-coagulant fixatives?
B- Define the following terms?
2. Glutaraldehyde is frequently used to fix specimens for electron microscopy .( )
3. Acetone is sometimes used when a rapid acting fixative is needed. . ( )
4. Heat and desiccation are methods of fixation. ( )
5. Very high temperature will cause friability of the specimen. ( )
6. Hard wax used with soft tissues (embryonic). ( )
7- Muscle is cut both transverse section and longitudinal planes . ( )
8- The best sections are obtained from paraffin blocks that are cool and moist . ( )
9- Tissue is usually fixed in 10% buffered neutral formalin for 24 hours for small specimens (5x5x5 mm) . ( )
10- Decalcification is a process of complete removal of calcium salt from the tissues like bone. . ( )
11- The commonest clearing agent is Xylene. ( )
12- After clearing, the specimen would be transferred carefully into melted wax inside the oven. ( )
13- Some tissues eg. cartilage are difficult to flatten on the water surface. ( ).
14- Drying section on a hot plate is necessary if staining is to be carried out urgently . ( ).
D- Read each question and then circle the correct answer.
1. For best results when using formalin as a routine fixative, it must be made:
2. Autolysis of tissue is caused by:
a. enzymatic activity
b. bacterial action
c. aqueous fixatives
3. To prepare a 10% solution of formalin, which of the following amounts of water should be added to 100 ml of stock formaldehyde:
a. 1,000 ml
b. 900 ml
c. 450 ml
d. 10 ml
4. After fixing tissue in Bouin solution, the excess picric acid is frequently removed by washing in:
a. running water
b. absolute alcohol
c. 70% alcohol
d. phosphate buffer
5. Carnoy fluid is prepared with acetic acid, alcohol, and:
d. osmium tetroxide
6. Fats are usually preserved best if the tissue is fixed In:
a. osmium tetroxide
7. Generally, an increase in the temperature of the fixative solution:
a. decreases the tissue autolysis
b. decreases the fixative penetration
c. increases the speed of fixation
d. increases the volume of fixative needed
8. Which of the following may cause tissue to become overhardened?
a. prolonged fixation
b. abbreviated fixation
c. inadequate dehydration
d. incomplete clearing
9 - used in dehydration:
c- All (a, b, c )
10- Hematoxylin will not directly stain tissues, but needs:
With best wishes…