Results: Figures 1 and 2 are taken from the H&E staining of ourmain sample under the magnifications of 4X and 40X respectively. Figures 3 and4 show the results of the PAS staining of the tissue sample at the samemagnifications of 4X and 40X respectively. Looking at the images, we see thatthe tissue contains open channel like spaces separating the groups of cells fromeach other. The staining’s show that the cell type most commonly found in thistissue sample are acinar cells. The PAS staining method, which helps visualizecarbohydrate containing compounds seen in figures 3 and 4, especially thehigher magnification reveals that there are small concentrations of carbcontaining compounds in the cells and also in the channels between them.Figure 5 is taken from the H staining of anothergroup’s tissue sample under the magnifications of 4X.

There is no 40X image asthe image was actually of the PAS stain. Figures 6 and 7 show the results ofthe PAS staining of the other groups sample at 4X and 40X respectively. Byobserving these images we can see that the cells in this tissue sample areseparated by sinusoids. There is also the presence of larger round openingswhich seem to be veins or ducts. The PAS staining images are also fairly darkwhen viewed, which would indicate that there is a high carbohydrateconcentration in this organ or high concentration of carbohydrate containing compounds.Discussion: During the course of this Histology lab, we have learned todo two different cell staining techniques currently used in research studiestoday, H&E and PAS.

This has allowed us to visualize the differentcomponents of the cells in the tissue such as the nucleus, cytoplasm, and anycarbohydrate containing molecule. This has allowed us to have a better idea ofthe types of tissues we are dealing with in our samples and have proceduralknowledge that will help us later on in our lab careers. When looking at theresults of our main tissue sample, the identification of acinar cells in groupsbeing separated by channel like passages has led me to believe that the sampleobserved is from that of a mouse pancreas. When looking at the results of theother groups tissue sample, the identification of sinusoids, separating columnsof cells, funnelling into a larger opening, has led me to believe that thesecond sample is that of a mouse liver.I believe the first sample to be that of a mouse pancreasdue to many reasons. The first is the identification of the acinar cell typeseen in figures 2 and 4, usually seen in organs with an exocrine function. Thisreduces the number of possible organs this sample can be from. When we look atthe literature of Longnecker, we see that the figures obtained in the lab arevery similar to the ones shown in his paper.

The H&E staining, figures 1and 2, of the acinar cells were similar with the nuclei of the cells being morepreferentially situated at the edges of the cells. The second is that the cellsof the tissue in the literature and our figures also make groups, and areseparated by small channels, which connect to the larger channels in thesample. PAS staining revealed little specks of carbs or carb containingmolecules in the cells and the passages.

This could be some of the sugars leftin the cells after the preparation steps of the sample as sugar is known totravel to the pancreas. These traits point towards the tissue sample being froma mouse pancreas. The identification of an islets of Langerhans would have madethis decision definite as they are only found in the pancreas.I believe the sample obtained from the other group is thatof a mouse liver.

The first clue that led me to this decision is the identificationof portal vein and a central venule in the low magnification images of thesample. The central venule can be clearly seen in the high magnification imageof the sample in figure 7. This is clear as there are cells emanating from itin rows, separated by small channels. When we look at the literature ofRoberston et al., we can see that these structures located in the tissue sampleare called sinusoids, and the rows of cells are hepatocytes. The portal veinseen in figure 6 can also be clearly seen with what looks like the bile ductand the hepatic artery located inside as well. When looking at the PAS stainedsamples of tissue, we can see that the images are fairly dark when compared toany of the other images obtained in this lab. This would indicate that thistissue sample had a high concentration of carbohydrates or carb containingmolecules.

This further solidifies my assumption that this sample is from aliver, as the organ is responsible for the storage and break down of glycogen,which is a glucose analogue. These traits are what would normally be seen in aliver, and point this sample in that direction. This classification also makesit easier to classify the first sample as a pancreas, as it was an exocrineorgan, and not many large organs have exocrine function other than the pancreasand liver.Our execution of these techniques were most likely faulty inone way or another due many errors. The main source of error for our lab wasprobably human error. We take time to move, and these techniques require propertime management while inside these staining solutions.

This leads to thesamples either spending not enough time submerged in the current solution ortoo much time. This can cause the staining of the cell to be abnormal,obscuring your ability to visualize your tissue samples under the microscope.Also one of the steps required the submersion of the sample slide in Eosin Yfor a few seconds, which was probably different for every group. Some of thedifficulties of preparing a histological slide is the handling of the tissuesample on the slide, as they are not covered, they can easily be removed fromthe slide, or parts of the sample could be lost due to incorrectly followedinstruction, which can lead to your sample looking different from what itshould.

Other techniques that could have been used are immunohistochemistry andantibody binding (3). Immunohistochemistry is the use of an antibody attachedto a detection method that when bound to its specific target can be used todetermine the targets location or relative amount. This can be used inhistological analysis’ to find specific target locations in tissue samples suchas the islets of Langerhans in the pancreas, or specific regions of the lymphnode.(4)

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