White Blood Cell Essay - Grade: 8 PDF

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White Blood Cell Count Abstract This lab report consists of investigating the proportions of different white blood cells in a blood sample of a healthy clinical trial volunteer. Part 1 of this lab report looks at 5 different types of white blood cell types (neutrophils, lymphocytes, monocytes, eosinophils, and basophils) and their cell count in 15 blood smear micrographs and percentage results recorded in table as shown In Figure 1 and the % of different white blood cell in the 15 blood smear micrographs in a form of a bar chart in Figure 2. Part 2 of this lab report is to prepare two labelled scientific drawing of a histology transverse section of a small intestine that is stained in H&E. There are two scientific drawings fully labelled one in a low magnification of x40 and another one in a high magnification of x100. The findings of the differential cell counts show that neutrophils were the most common type of white blood cell and basophils was the least common. The percentages of white blood cell types somewhat correspond to the normal range. Haematoxylin and eosin stain were the type of staining that was used for the provided histology section micrographs for Figure 3 & 4. Introduction In this study it was asked to investigate the proportions of different white blood cells in a blood sample of a healthy clinical trial volunteer. The normal white blood cell count of a healthy person is ranged from 4,500 to 11,000 white blood cell per microliter. White blood cells are a part of the body’s immune system. They help fight infection and other diseases. The types of white blood cells are granulocytes which include (neutrophils, eosinophils, and basophils), monocytes and lymphocytes which are T and B cells. White blood cells can be recognised through microscopy. All white

blood cells are over 5 micrometres in diameter which means they are large enough to be seen using a typical optical microscope. Staining the white blood cells with Leishman’s stain helps to easily identify different types of leukocytes but also be able to count them. The least common white blood cells and the rarest is Basophils. They are the least common white blood cells and they only make up 1% in a blood smear. Basophils play a role in preventing any blood clotting. They contain heparin which is a natural occurring blood-thinning substance it helps mediate allergic reactions. Whereas neutrophils also known as polymorphonuclear leukocytes are the most common and abundant white blood cells which make up between 60-70% of the cell. Neutrophils kill and digest bacteria and fungi. They are the most numerous types of white blood cell and it is the first line of defence when the infection strikes. An elevated high white blood cell count usually indicates there is an increased production of white blood cell to fight an infection. A reaction of the drug is what increases white blood cells production. A disease such as bone marrow may also cause abnormal high production of white blood cells. This means that it could indicate any infection, inflammation, tissue necrosis, or leukemic neoplasia. Trauma or stress either physically or emotionally may also be a reason for high WBC count (white blood cell). This is important because it is essential for health and well-being. [ CITATION Nal20 \l 2057 ] A histological section is a technique used to study tissues using a microscope. It requires tissues to be preserved and cut into section thin enough to be translucent. Histology is a study of ow tissues ae structured and how they work. Knowing what a normal tissue looks like and how it works is important for recognizing different types of diseases. This technique also helps to identify diseases. It also helps in discovering what is the cause of certain diseases, and how it can be treated and

whether the treatment has shown any improvement. The most common histological stains are Haematoxylin and Eosin. Haematoxylin is used to illustrate nuclear detail in cells, Depth of coloration is not only related to the amount of DNA in the nuclei but also to the length of time sample spend in haematoxylin e.g., nucleus which gives a blue stain. Eosin can be used to stain cytoplasm, red blood cells, collage, and muscle fibres for histological examination this gives a red or pink stain. To Investigate the proportions of different white blood cells in a blood sample of a healthy clinical trial volunteer. Th aim of this investigation is to count the number of different types of white blood cells on each region of interest in each photograph given and then calculate the total percentage for each cell type. Another aim to identify the type of histology stain on the slide and prepare a scientific drawing of tissue at a high and low magnification. Hypothesis The blood sample that was analysed is from a healthy volunteer therefore the percentage of white blood cell types will be in the normal range for five different white blood cell types.

Materials and Methods

Blood smear preparation Blood smear is prepared by firstly using the haematocrit tube to transfer the sample from the collection tube to the slide. Then one drop of blood is placed on the frosted area of the slide. A second clean microscope slide is then used to create the smear. This step was carried out quickly to avoid the blood droplet to dry and clump. The slide is then positioned at a 34 ℃ where the spreader slide has been the backed into the blood droplet, this has caused it to spread across the width of the slide via the capillary action. The blood is then dragged along the slide behind the spreader slide. The blood is smeared at a constant pressure but firmly at a fast speed away from the blood droplet. The spreader slider is the either cleaned or can be disposed according to the local waste disposal procedure. Finally, the smear is air dried for it to be prepared. Blood Smear Micrographs Using the 15 blood smear images the different white blood cell types (Neutrophils, Lymphocytes, Monocytes, Eosinophils, Basophils) were identified from random regions in the image. The Giemsa-stain helped to analyse and identify the different white blood cells. The differential cell counts were identified and were completed in the table. Scientific drawings For a low power micrograph, the drawing took between a third and a half sheet of A4 landscape paper and the remaining space on the page was used at a later step for labels. Firstly, the pencil was used to draw the boundaries between the different tissue types. After the boundaries were drawn on small detail was added to the drawing. The areas that were stained darker or were naturally dark as shown on the

photograph they were indicated with a sharp pencil using the stippling technique. Labels were then added using a sharp pencil and a ruler to draw out a straight line between a feature and a label and then labels itself were written in a black pen. A clear title using a black pen was written above the low power micrograph drawing and the scale bar or the magnification factor was addressed below the drawing. For a high-power micrograph, the drawing took place between a third and a half sheet of A4 landscape paper and the remaining space was used at a later step for labels. Using a sharp pencil, boundaries were drawn on between the different cell types. Then a representative area was selected, and visible features were drawn on within this area. However, not every cell was necessary to be drawn on within the field of view. After the outline of representative cells were drawn, internal and external features of the cell was added onto the drawing. The areas that were stained darker or were naturally dark as shown on the photograph they were indicated with a sharp pencil using the stippling technique. Labels were then added using a sharp pencil and a ruler to draw out a straight line between a feature and a label and then labels itself were written in a black pen. A clear title using a black pen was written above the low power micrograph drawing and the scale bar or the magnification factor was addressed below the drawing. Preparation of samples for blood smear For the blood smear preparation, a drop of blood is spread on a slide and the cells on the smear are fixed using 95% of ethanol for approximately 2 minutes. After the 2minute timing has been completed the slide is then immersed in the buffer for a minimum of 5 minutes. After 5 minutes the droplets are shaken off the slide and the smear are stained using Giemsa solution for approximately 15 – 20 minutes. The

slide is then rinsed in buffer, the slide is immersed several times. After this step, the smear is covered with a cover slip and is examined using a x40 objective on the microscope.

Results

Figure 1- a table that contain cell counts of each different types of white blood cell that are present on the 15 blood smear micrographs and the % of each white blood cell.

cells counted

Neutrophi

Lymphocyt

Monocyt

Eosinophi

Basophi

in each

ls

es

es

ls

ls

field

5

0

0

0

0

5

1

1

0

0

0

2

4

3

0

0

1

8

2

1

1

0

0

4

6

1

0

0

0

7

3

0

1

1

0

5

3

1

0

0

0

4

3

1

0

0

0

4

2

1

1

0

0

4

2

2

1

0

0

5

4

0

0

0

0

4

Field 1 Field 2 Field 3 Field 4 Field 5 Field 6 Field 7 Field 8 Field 9 Field 10 Field 11

Field 1

1

0

0

0

2

4

0

0

0

0

4

3

1

0

0

0

4

15

2

0

0

0

0

2

Total

45

13

4

1

1

64

%

70.3125

20.3125

6.25

1.5626

1.5625

100

55-70

20-40

2-8

1-4

0.5 - 1

12 Field 13 Field 14 Field

Figure 1 is a table that shows Neutrophils is the most common white blood cell and Eosinophils, and Basophils is the least common white blood cell and its very rare.

Total % of White Blood Cell in each feld

80 70 60 50 40

Figure 2 is a bar

30 20

chart that shows

10

the different cell

0 Neutrophils

Lymphocytes

Monocytes

Eosinophils

Basophils

Different types of White Blood Cells

type percentage

results. The most common white blood cell is Neutrophils and the least common are Eosinophils. Basophils is a rare white blood cell. Figure 2 – A bar chart displaying the different white blood cells percentage results in the 15 blood smear micrographs using Ca Fig.1 to calculate the % and to produce a bar chart.

Neutrophils = 45/64 x 100 = 70.3125% Lymphocytes = 13/64 x100 = 20.3125% Monocytes = 4/64 x100 = 6.25% Eosinophils = 1/64 x100 = 1.5626 Basophils = 1/64 x100 = 1.5626

Figure 3 – A low power micrograph (x40). A scientific drawing of a histology section showing the transverse section of small intestine stained with H&E and showing the muscular layer.

Figure 3 shows a low magnification of a histology section in a form of scientific drawing of a human intestinal that is stained with H and E and is showing a muscular layer. This fig.3 shows a brief outline of the transverse histology section.

Figure 4 – A high power micrograph (x100). A scientific drawing of a histology section showing the transverse section of small intestine stained with H&E and showing tall cylindrical villi.

Figure 4 shows a high magnification of a histology section of a small intestine that is stained with H and E and it is showing a tall cylindrical villa. This fig.3 shows a detailed image and annotation of a transverse histology section in the small intestine.

Discussion Figure 1 shows a table that contains cell counts of each different types of white blood cell that are present on the 15 blood smear micrographs and the % of each white blood cell. There are 5 different types of white blood cells that were used (Neutrophils, Lymphocytes, Monocytes, Eosinophils, Basophils). Figure 2 shows a bar chart the % of each white blood cell type. This bar chart includes the 5 different white blood cell types and the average overall percentage. Figure 3 shows a scientific drawing of a low power micrograph, which is a human small intestine histology section. This is a brief drawing that is annotated with key labels of different parts of the section that was drawn. The stain that was used for this histology section of a small intestine was Hematoxylin and eosin stain. Figure 4 shows a scientific drawing of a high-power micrograph, which is a human small intestine histology section. This is a high detailed drawing that is annotated with key labels of different parts of the section that was drawn. The stain that was used for this histology section of a small intestine was Hematoxylin and eosin stain. There are no overall trends and patterns in the results. As shown in Figure 2 from the overall white blood cell percentage 70% of white blood cell is Neutrophils. As shown in Morris (2018), the Neutrophils are one type of white blood cell and are the most common type that make up between 50 and 70% of them. Figure 2 also shows from overall white blood cell percentage 20% of white blood cell is Lymphocytes. As shown in Gray (2018), the normal range of lymphocytes range between 20 and 40% of the total white blood cell count. Monocytes in Figure 2 shows from the overall white blood cell percentage 6% of the white blood cell is Monocytes. This result is supported by Pietrangelo (2021), as this shows the normal % range of monocytes is

between 2 to 8%. The % level of white blood cell of Eosinophils in Figure 2 shows that it makes up 1% of the overall white blood cell. This finding is supported by Gray (2018), as this shows the normal range of eosinophils is varied between 0 and 4%. Basophils is the rarest type of white blood cell and shown in Figure 2 from the overall white blood cell % it makes up only 1%. According to Bhavsar and Hedge (2017), it shows basophils are approximately make up between 0.4 to 1% of white blood cell. The results address the aim of the study as the aims of this investigation was to count the number of different types of white blood cells on each region of interest in each photograph given and then calculate the total percentage for each cell type. Another aim for this study was to identify the type of histology stain on the slide and prepare a scientific drawing of the small intestine histology section, at a high and low magnification. The low magnification required a brief outline of the small intestine, which was labelled, whereas the high magnification required and in-depth detail scientific drawing of the small intestine which was labelled. The null hypothesis can be accepted as the white blood cell was within the normal range of a human white blood cell count. The normal range for white blood cell for the 5 different types are the with the same range as the finding in Figure 2.

Errors, Limitations, and Improvements There were some difficulties encountered when performing the work. This is because these were secondary set of results. The methods were accurate and precise this is because the blood smear method this is because this method carries out an observation using a microscope which means the results are precise.

Variables Controlled variable The controlled variable of this investigation is the technique used in to make the preparation for the blood smear. It also includes keeping the same 15 blood smear micrographs that were used to make the table. Dependent variable The dependent variable was the number of different types of white blood cells in the healthy trial volunteer’s blood smear. The different white blood cells were measured in the smear.

Limitations A limitation for the preparation of blood smear method can be, once the drop of blood has contact on the slide, the smear needs to be made immediately. Otherwise, the blood will clump up and dry and this would result in uneven distribution of white blood cells and therefore could produce inaccurate set of results. An improvement would be to make the smear very quickly as this would provide precise results. Another limitation can be the glass slides may be contaminated; therefore, this would result in imperfect distribution of cells and improper staining. An improvement would be to thoroughly wash the glass slides with a buffer solution and dry them properly. Sample size could also be a limitation. This is because the size of the sample was small therefore the results can lack accuracy, this could mean the level of confidence in the set of results is low. An improvement would be to increase the sample size as this would lead to a range of different set of results, which would then determine the average and the precision levels of the results would be high. Unlabelled histology sections of small intestine can be a limitation. This is because the labels show a clear identification of the different parts of the cell which shows what it is. An improvement would be to have accurate labels of the different part of the cell in a black pen and using a sharp pencil and a ruler to draw a straight line from the label and the part of the cell. Reliability and Variability The data was not reliable this is because each smear in the micrograph was done at a different type and speed therefore the white blood cells count have been different. This means the results were not consistent over time and the white blood cell count

can vary between number due to a different time scale. This is known as an observational error. There can also be a Human error as the objective lens may get wet when observing a wet mount of blood smear. This would mean the image becomes distorted when the objectives do not make contact with the cover slip or slide, the image can show different blurry micrograph images of white blood cells. Figure 1 and 2 show the data has a range of variability, as the 15 white blood cells micrographs images show there is 70.3% of neutrophils which is the most common type of white blood cell, 20.3% of lymphocytes, 6.25% of Monocyte, 1.56% of Eosinophil, 1.56% of Basophils which is the least common type of blood cell. According to this data, the results ranged from 1.5% to 70.3%. The range of the set of data is 68.74% of the overall white blood cell. = 70.3% - 1.56% = 68.74% The inter quartile range of the set of data is 35.93%. = 70.3 % + 1.56% = 71.86% 71.86 / 2 = 35.93% 35.93 / 2 = 17.96% 35.93 + 17.96 = 53.89 53.89 – 17.96 = 35.93% Standard deviation: 1.56% + 1.56% + 6.25% + 20.3% +70.3% = 20% (Mean)

S2 = Σ (xi - x )2 / N-1 = (1.56 - 19.994)2 + (1.56 – 19.994)2 + (6.25– 19.994)2 +(20.3– 19.994)2

+ (70.3

- 19.994)2 / 5-1 = 4 = 3399.30952 / 4 = 849.82738 s = √849.82738 SD = 29.151798915333 The data that was collected is both qualitative and quantitativ...