rtant ingredients in our body, despite only making up a very small percentage of our blood. They make a huge difference and yet you may never have heard of them. What are they exactly? What do they do for us?
We’ve got all the scientific know how for you! Below, you’ll find a complete breakdown of white blood cells, including exactly what they they are and how they help all of us.
On top of that, you’ll find a detailed explanation of how you can observe them under microscopes, as well as what you should look for when examining your findings. Read on and find out all about white blood cells!
What Are White Blood Cells?
So, the big question. White blood cells, also known more scientifically as leukocytes, are cells in our bodies that make up an important part of its immune system.
This is the network that makes sure that we are protected and immune from deadly threats, such as bacterias and viruses, or even cancerous cells.
White blood cells comprise about 1% of our total blood volume, which doesn’t seem like a lot. This is especially true when compared to red blood cells, which deliver oxygen to our body tissues.
How much do they make up our blood volume? Anywhere between a massive 40 to 45 percent! That being said, the white blood cells make a huge difference, despite how seemingly few there are.
Without them, our bodies wouldn’t have their immunity, and we would more frequently fall for illnesses.
Types Of White Blood Cells
There are many different types of white blood cells, and we’ll be going into how you can spot them later. In the past, the types came under two broad headings, determined by their appearances: “granulocytes” and “agranulocytes”.
Basically, the difference between the two is that granulocytes have granules in their cytoplasm, while agranulocytes do not.
The types that fit into these categories includes: eosinophils, neutrophils, basophils, mast cells, monocytes, lymphocytes, macrophages, and dendritic cells. That may seem like a lot, but we’ll be going into them all later!
What Do The Different Types Do?
Before we get into how you can observe and count them, let’s have a look at what different types of white blood cells do best.
These types of white blood cells ingest invading threats (like viruses and bacteria), destroying them. Basically, think of it as something eating another thing in order to get rid of it.
To move around the blood, monocytes use adhesion molecules to get by, adhering to vascular endothelium (the inner cellular lining of arteries, capillaries, and veins) in order to reach target sites.
Additionally, monocyte cells can transform into dendritic cells (mentioned earlier). Here they process antigens and allow antibodies to destroy bacterial and viral threats too.
Lymphocytes carry many roles, which are divided by the different types of the cell that there are. T lymphocytes, also known as T cells, take the role of destroying cells that have been infected or damaged in some way.
Similarly, the other type – B lymphocytes – dedicate their attention to destroying certain antigens.
A type of granulocyte, the eosinophil white blood cell goes around to different sites where they are involved in allergic reactions. It gets to all these different sites by adhering to other things in the blood.
These are the most common type of white blood cell in our blood stream, and as such they are the first line of defense. Their big role is that they use chemotaxis (movement because of an extracellular chemical gradient) to go and find invading threat organisms.
When they reach these harmful things (whether they’re bacteria or viruses) they engulf them, destroying them through a technique called phagocytosis. Basically, picture it as swallowing the enemy up!
These white blood cells help your tissues decrease your blood pressure. They do this by traveling to the tissues (sometimes using vascular endothelium, which we mentioned with Monocytes) and release inflammatory chemicals.
This then does things like constrict the smooth muscles, or dilate the blood vessels, all of which help to lower your blood pressure and keep you in good health.
Observing White Blood Cells Under A Microscope
To identify and count your white blood cells, you can view them underneath a microscope. Each cell is at least 5 micrometers by diameter, which is thankfully big enough to see through a compound microscope.
To view them, you’ll need:
- A compound light microscope
- Blood sample
- Microscope glass slides, and coverslips for them
- Leishman’s stain (see below)
- Buffered distilled water
- Dropper and dropper bottle
- Oil immersion (for greater magnification)
- Drying rack
You may be wondering what Leishman’s stain is, but don’t worry. Put simply it’s a mixture of eosin and methylene blue that are dissolved in methanol.
The stain is used for staining blood smears, and helps to identify white blood cells, among other things.
Preparing Your Slide
Follow these steps very carefully.
- Take your blood sample and store it in an EDTA tube.
- Take your dropper and collect a drop of blood from the tube, before dropping it onto one side of a glass slide.
- Take another glass slide and use it to spread the blood around the other slide.
- Wait 5 minutes for it to dry.
- Take a dropper bottle with Leishman’s stain in it and flood the smear with it.
- Wait 2 minutes.
- Take some buffered distilled water (water that resists a pH change when ions are added) and flood the slide again. This will make the liquid weaker.
- Wait 10 minutes.
- Spending a minute washing the slide with some distilled water. The smear should turn pink.
- Take the covered slide and put it upright on a drying rack.
- Leave it to dry. If there’s any dripping, carefully wipe it, making sure not to spill too much.
- Once it’s dry, take the slide and put it on the stage of your microscope.
Observing Your Slide And Identifying The Cells
Now that your slide is dried and set up on the stage, it’s time to observe your sample. The guide below will tell you what to look for, helping you to identify exactly what type of white blood cell you’ve got.
Let’s start with agranulocytes, which don’t have granules in their cytoplasm.
These are larger than lymphocytes, another type of agranulocyte, as well as having more cytoplasm in them – look out for that. Also, you can spot their nucleus by looking for a bean-shaped thing.
These have a very large nucleus, on the other hand, which makes up most of the cell. You’ll be able to tell your cell is a lymphocyte, because most of it will be taken up by a shape of a different shade to the rest.
As a result of this size, they have little space for a cytoplasm.
There are many more variations of these, which all have granules in their cytoplasms.
These usually have only 2 lobes in their nucleus, which takes the shape of something like a horse shoe, but can have 3 in rarer cases. The cytoplasm is coarsely granular, with refractile orange granules that surround the nucleus.
These have a nucleus that is made up of anywhere between 2 to 5 lobes, and their nucleus appears dark. Neutrophils are shaped like a sphere, and will contain fine granules.
These have a blue color to them, which is caused by their dark violet granules. The nucleus of a basophil has 2 or 3 lobes, but is often hard to distinguish, because the many coarse granules that the basophil has can often obscure it.
These look similar to basophils. They take the shape of a sphere and have a big nucleus that’s swamped with granules.
Counting The White Blood Cells In Your Sample
Doctors regularly perform a complete blood count when assessing a patient’s blood, revealing the amount of cells that are in it. This includes white blood cells and red blood cells, as well as platelets and the concentration of hemoglobin.
A count of white blood cells is especially important, because too many or too few in the blood can suggest a disease.
So, you’ll want to count how many white blood cells are in the blood. However, there are two ways that you can do this: automatic or manual. A bit like driving a car!
Below, you’ll find all about how to do these types of counts, leaving you with an answer of how many white blood cells are in the blood sample.
Automatic White Blood Cell Counting
Automated counters are used an awful lot, because they offer far more reliability than manual counting. For a start, automated counters have a higher accuracy, as well as a much quicker speed.
This means that doctors and scientists can get their results quicker, and get working on solutions if the results are troubling. The speed is because it can simultaneously analyze and characterize mixed populations of cells, identifying multiple at a time.
If a human were doing it, they’d have to identify them one by one, taking ages to see to them all.
But how do they perform automated cell counts? Well, a “flow cytometry” is often used. This is a laser based technology that rapidly analyzes cells as they flow past single (or sometimes multiple) lasers.
To keep them grouped and unaffected, the cells are suspended in a buffered salt based solution. This technology is also used to analyze bone marrow, or even other fluids from your body.
There are some downsides, though. For one, it cannot identify the shape or the morphology of the white blood cells. This refers to the structure and the form, as well as their color.
Additionally, the automated counting machines are very expensive, meaning that they are not prevalent all over the world – and therefore won’t be used in every case.
To this degree, they are also very sophisticated machines, and as such require training and specialist use.
That being said, they are still remarkably helpful. So how do they work?
Removing The Red Blood Cells
Well, to begin with, the blood sample needs to be tended to and changed. Basically, the red blood cells need to be removed from it, because they can contaminate it and affect the results you’re actually looking for.
Removing the red blood cells from the sample is a part of a process called “lysing”, which is where a cell’s membrane is broken down so that materials inside it can be released – in this case, red blood cells!
To release and remove these cells, solutions of ammonium chloride are used. It causes the cells to swell and rupture the membrane.
Ammonium chloride is a popular solution for it because it is specially buffered to gently lyse the red blood cells while having a very minimal effect on the white blood cells.
The Solution Goes Through The Flow Cytometry
Now that the blood sample is free of its conantiment, it can be put through the flow cytometry machine. First it needs to be suspended in a salt based solution.
This then flows through a series of electronic detectors, which analyzes and determines the properties of all the different kinds of white blood cells.
This means that the different types can then be counted in their own groups, allowing for more accurate results.
Now the type of flow is altered lightly, so that the sample suspension is done as part of a “laminar flow”. But what is this? A laminar flow is when a fluid flows in parallel layers, in other words alongside each other in the same direction.
This laminar flow makes it possible for individual blood cells to go through an interrogation point, which is a process also known as hydrodynamic focusing – a single file stream going through the interrogation point.
The interrogation point is also known as the laser intercept, where the cells interact with laser light. When the laser beam illuminates each individual cell, it hits the structures within the cell and therefore scatters all around.
This scatter is then measured and looked at against the cell size and structures. That, as well as other light that is emitted, is all collected by the detector – and then that light is analyzed to get the readings that you want.
Manual White Blood Cell Counting
On the other hand, you can try to do it manually – though keep in mind that it is slower and less accurate. A common manual method is to count by region.
What do we mean by counting by region? Well, if you divide your smear up in your head, and count the number of white blood cells in each of those areas, you can calculate a (probable) percentage of each type.
Let’s use an example. If you look at your sample and count 6 lymphocytes from two of your regions, and then a total of 10 white blood cells all in all, then you could work out how many lymphocytes are going to be there.
To do that, do (6/10) x 100 which will give you a result of 60 percent.
This isn’t the only manual way, though, because you can also use a hemocytometer attached to your microscope. This is a device that has 9 squares for viewing.
However, only 4 of these are for counting white blood cells, so make sure to use just those – which happen to be each of the corner squares of the 9.
To use it, put a few drops of cell suspension between the hemocytometer and cover glass, then count the number of cells in each grid – giving you numbers to work out the total percentage in the whole sample.
What Does The White Blood Cell Count Mean?
Whether you’ve used automated or manual counting methods, you should now have an idea of: what kind of white blood cells are there, and how many there are of them.
With these details and statistics, you can find out a lot. Below, you’ll see what they all mean.
Keep in mind that a healthy adult should have anywhere between 4500 and 11,000 cells in each microliter of their blood.
Typically less than 10% of your white blood cells.
If you have abnormally low numbers of monocytes, it could be an indicator that you have a viral infection. If not that, it could suggest autoimmune or congenital disorders.
Congenital disorders are conditions that a person has had from birth.
On the other hand, if there are abnormally high counts, then it could suggest cancer. If not, then it could be chronic infections or (like low) autoimmune disorders.
Typically 18-45% of your white blood cells.
An abnormally low count could suggest HIV or other autoimmune disorders, as well as simply a poor diet lacking in nutrition.
An abnormally high count could be certain lymphomas and cancers, or it could be less severe: viral or bacterial infections.
Typically 1-6% of your white blood cells.
Abnormally low counts of this are actually normal, since humans should have a low number anyway.
On the other hand, abnormally high counts of eosinophil cells could be signs of an asthmatic reaction. Similarly, it could mean that you’ve had an allergic reaction, or are suffering some sort of parasite.
Typically 50-75% of your white blood cells.
An abnormally low count of neutrophils could be linked to autoimmune disorders, or some sort of disorder to do with bone marrow. Additionally, it could be a result of some cancer treatment.
Abnormally high counts, on the other hand, could be a sign that the person has an inflammation or infection going on in their body and blood. If not, high neutrophils could be a sign of a certain variety of leukemia.
Typically 3% of your white blood cells.
Abnormally low counts of this could also be a sign of leukemia. Additionally, it can indicate thyrotoxicosis (where you have too many thyroid hormones in your body) or some infections.
Abnormally high counts could indicate some cancers, or could be a sign of conditions like hypothyroidism (where your thyroid gland doesn’t produce enough hormones).
Testing For White Blood Cells In Urine
- Put your urine sample in a test tube.
- Shake it at low speeds (around 2000 rpm) for 5 minutes – using a centrifuge.
- Pour out the liquid, leaving about 0.4 ml in the tube.
- Get a dropper and place a drop of the suspension liquid onto a glass slide.
- Put the coverslip over it carefully.
- Put the slide onto the stage of your microscope, beginning with low power and working your way up.
Observing White Blood Cells In Urine
Now it’s time for observation! If you notice an abnormally high number of white blood cells in the urine sample, then this could be signs of an infection – whether it’s in the urinary tract, or the related kidney.
This high number of cells is called pyuria, and is quantified by having 10+ white blood cells per cubic millimeter of urine. Though most cases of pyuria aren’t serious, you should still take it to a doctor and get them to find the cause.
They, especially if it’s a UTI mentioned earlier, can often be treated just with antibiotics.
If you use low power and low magnification, you may only see other things in the urine – for example, crystal shapes. If this is happening, increase the magnification power, which should allow you to see more clearly.
And there you have it! It’s been long and scientific, but this guide should have helped you more easily understand just what white blood cells mean to you and your health. They’re pretty crucial!
Without them, we would fall to illness and disease much more easily.
Now you have a good idea of the many different types of white blood cells there are, as well as how to tell the difference between granulocytes and agranulocytes (think granules!).
On top of that, you also now know what kind of number of each type you should have floating about – and what too many or too few could mean for you.
Plus, you’ve enjoyed a guide on how to observe and count them yourself, using slides and a microscope. Remember, though, always get a professional scientific or medical opinion if you think you’ve found something!
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