Lab 1 - Introduction and Cytology

Question 1

What is involved in the process of fixation/what does it do to cells

Answer 1

its a physical and chemical process that halts cell degradation and tissue breakdown, kills micro-organisms that cause putrefaction and preserve molecular components
-provides long term stabiliztion of cellular and tissue components

Question 2

what is the most common chemical fixation

Answer 2

-is a solution of formaldehyde called formalin

Question 3

What are the benefits of using TEM

Answer 3

TEM allows for much greater resolution due to the high energy of the electrons employed and the thinner sections used. It also allows for greater magnification and can reveal ultrastructures of tissues and cells.

Question 4

what chemicals are used for TEM fixation

Answer 4

-gluteraldehyde and osmium tetroxide. Osmium tetroxide has the ability to break open chemical bonds to deposit itself in cellular molecules

Question 5

what is the purpose of embedding?
what is most common in LM?
what is used in TEM?

Answer 5

-it stabilizes ths tissue and surrounds it with a firm substance
-paraffin is most common in LM, it is firm at room temperature but liquid at higher temperatures
-TEM uses plastic resins like epoxy instead because its needs to be a harder substance

Question 6

what is unique about lipids in cryosectioning?

Answer 6

they are not extracted from the tissues due to there not being solvents used. I think this would cause lipids to appear when viewing?

Question 7

what cant be bound in H+E staining?

Answer 7

carbohydrates or lipids. special dyes must be used to visualize these aspects

Question 8

what is unique about TEM specimens when it comes to visualizing a certain aspect

Answer 8

we can visualize lipids in cells and tissues because the osmium tetroxide used deposits itself in the unsaturated bons of fatty acids and phospholipids. they will appear black

Question 9

what do the pancreatic acinar cells do?

Answer 9

they synthesize large amounts of digestive enzymes for transport to the duodenum. the proteins are stored in cell storage vescicles called zymogen granules, until the cells are signalled to release the enzymes after a meal.

Question 10

what is toluidine used for?

Answer 10

its a general protein stain, so the proteins will be stained well and the nuclei will be poorly stained.

dont be confused about the blue/purple colour here!

Question 11

what is alcian blue used for

Answer 11

it is a common polysaccharide stain and they stain turquoise. Nuclei appear kinda grey blue rather than purple.
You can see things like goblet cells well in these