Histology

Question 1

Why are cells fixated?

Answer 1

Stops decay, preserves morphology (structure), formation of X links within tissue

Question 2

Why is FORMALIN used for fixation?

Answer 2

Forms covalent bonds between proteins
Good tissue penetration
Not good for cytoplasmic structure or nucleic acids

Question 3

What are the advantages and disadvantages of freezing to fixate?

Answer 3

Good for nucleic acids, proteins etc

Poor for morphology

Question 4

What are the disadvantages of using glutaraldeyhde for fixation?

Answer 4

Poor tissue penetration

Question 5

What are the benefits of using wax to fixate?

Answer 5

Protects tissue
enables sectioning
not alcohol or water soluble
is soluble in other hydrocarbons

Question 6

What colour does haematoxylin stain acidic structures? Give an example

Answer 6

Blue or purple

e.g. DNA in nuclei

Question 7

What colour does Eosin stain basic structures?Give an example

Answer 7

pink

Proteins

Question 8

Basic structure and function of peroxisomes?

Answer 8

break down fatty acid chains producing hydrogen peroxide which is broken down to water and oxygen

Question 9

What is the cytoskeleton?

Answer 9

A network of microtubules and microfilaments that hold the cell structure together