Cells of the Immune System: Granulocytes - Video Tutorials & Practice Problems
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1
concept
Granulocytes
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3m
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In this video, we're going to begin our lesson on granulocytes, which are cells of the innate immune system. And so these granulocytes are white blood cells or leukocytes with visible cytoplasmic Granules, which is really implied by their name. You can see the Granules uh within their name. And so these Granules are cell structures that contain compounds that are used for protective functions and are visible under a light microscope. Now, really, there are three main types of granular sites that are named based off of the staining properties of their Granules. And so the first main type of granulocyte are going to be the neutrophils and the neutrophils actually have a nucleus with five lobes. So they have a five lobed nucleus and they have really small Granules which really do not stain very well. And so their Granules remain somewhat of a neutral color, which is why they're referred to as these neutrophils. Now, neutrophils are also sometimes referred to as polymorphonuclear neutrophils because poly is a root that means many and uh morone nuclear is talking about a morphed nucleus. And so uh these are abbreviated as PM NS. And so if we take a look at our image down below. Uh notice over here on the left hand side, we're showing you the granular sites and uh notice that we're showing you the neutrophils on the far left and notice that they have five lobed nucleus and uh their Granules are so small that they don't stain very, very well. Now, the next type of granulocyte that we have here are the eosinophils and the eosinophils have 2 to 3 lobes in their nucleus and they have larger Granules that stain a reddish orange color. And so if we take a look at our image down below, at the eosinophils, notice that their nuclei have uh 2 to 3 lobes and they have these larger Granules that stain a reddish color. And then the last type of granulocyte is going to be the basophils and the basophils have two lobed nucleus and uh they have larger Granules that stain a darker blue uh or purple color. And so if we take a look at the basophils down below over here, notice they have a nucleus with two lobes and they have these larger Granules that stain a purplish bluish color. Now, as we move forward in our course, we'll be able to talk a little bit more details about each of these different types of granulocytes, the neutrophils, eosinophils and basophils. And so this here concludes our brief introduction to the granular sites. And once again, we'll be able to learn more about them as we move forward. So I'll see you all in our next video.
2
concept
Neutrophils
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5m
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In this video, we're going to talk some more details about neutrophils. And so, recall from our last lesson video that neutrophils are one of the three types of granulocytes. And so these neutrophils are the most abundant type of leukocyte or the most abundant type of white blood cell in the blood. In fact, they can make up to 70% of all leukocytes in the blood, which is the overwhelming majority. And so uh these neutrophils, uh they also will be able to migrate to different locations via the bloodstream and uh they are able to respond to a site of infection or tissue damage. And usually they are going to be the first to respond to an infection or tissue damage. So they are going to be the first cells to be recruited to the site of infection or the site of damage. Now, the Granules that these neutrophils contain uh are going to have a variety of different antimicrobial peptides, including defenses as well as hydrolytic enzymes that have the ability to degrade microbes and destroy microbes. Now, the Granules themselves can also be released into the environment and uh this process of releasing the Granules is referred to as degranulation. And uh uh so these Granules, they can either be released through degranulation or the neutrophil could destroy the microbes during phagocytosis. And so, phagocytosis is the process of ingesting and digesting material that has been brought in from the outside. And this includes invading microbes. And so phagocytosis is sometimes referred to as cell eating. Now, another really interesting thing that these neutrophils can do is they can actually release neutrophil extracellular traps or nets which really act as webs of chromatin. So they essentially release their own DNA into the environment to serve as a net or a trap that will once again trap uh infecting microbes in their DNA that they release and trapping the microbes can be an important defense mechanism focusing specifically on these neutrophils at the moment. And so notice that these neutrophils again, they have these five lobes, they have these smaller Granules that do not stain very well. And here's an image of what a neutrophil could look like under a microscope. Now, uh notice that here, we're showing you an image of some kind of sharp object penetrating into the skin and penetrating tissue. And when a sharp object here penetrates into the tissue, it can create uh an area where microbes pathogenic bacteria might be able to enter into our tissues. And so notice that uh neutrophils are usually the first cells to respond to the injury and they're the first cells to be recruited to the site of infection or the site of damage. And uh notice that these neutrophils, they travel through the bloodstream and they're able to leave the bloodstream into the site of infection. Now, these neutrophils are geared to fight the pathogenic microbes to defend us from these pathogenic microbes. And so they can do this either via phagocytosis where they can uh ingest microbes and degrade microbes. They can also like what this neutrophil is doing. They can de granulate, which recall means they can release their cytoplasmic Granules into the environment so that those cytoplasmic Granules can act on those microbes and destroy the microbes. And they can also release those nets or those neutrophil extracellular traps uh or nets that once again serve as webs of chromatin to trap infecting microbes. And so notice here in this image right here, we're showing you a neutrophil that is uh releasing its net, its uh web of DNA to trap the microbes. And so uh these neutrophils, another thing they can do is they can also recruit other immune cells to fight the infection. And so notice that these uh wandering macrophages are also being recruited to this area so that they can also help fight off these microbes that have invaded. And so uh this year concludes our brief lesson on neutrophils and we'll be able to apply some of these concepts as we move forward in our course and also learn about the other granular sites as well, uh, including eos fills and basophils as we move forward. And so I'll see you all in our next video.
3
Problem
Problem
Which granulocyte is the first to respond to an infection, has hydrolytic enzymes in its granules, and possesses the ability of phagocytosis?
A
Basophil.
B
Eosinophil.
C
Neutrophil.
D
Macrophage.
4
concept
Eosinophils
Video duration:
1m
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In this video, we're going to briefly discuss eosinophils. And so recall from some of our previous lesson videos that eosinophils are one of the three types of granulocytes. And the primary role of eosinophils is to protect against parasitic worms or helmets. Now, the Granules of these eosinophils actually have antimicrobial substances that bind parasites and they also contain enzymes that disrupt the membrane permeability of those parasites. And so these eosinophils are geared to destroying and killing these parasitic worms or helmets that may try to invade and infect our bodies. Now, eosinophils can also be involved with the sy symptoms uh associated with allergies. And so we'll be able to talk a little bit more about allergies later in our course. And uh again, these eosinophils uh here we're showing you an eosinophil um and these eosinophil is uh going to contain these uh cytoplasmic Granules that can stain a reddish color and they can be released into the environment so that their uh antimicrobial substances and enzymes can help defend against uh parasitic worms such as this helmet that you see right here. And so uh these eosinophils again are important for defending against parasitic worms and helmets and can also be important for some of the symptoms associated with allergies. And so this here concludes our brief lesson on eosinophils. And once again, we'll be able to apply some of these concepts as we move forward. And then we'll get to talk a little bit about the last type of granular site, the basophils. And so I'll see you all in our next video.
5
concept
Basophils
Video duration:
3m
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In this video, we're going to talk some more details about basophils. And so, recall from some of our previous lesson videos that basophils are one of the three types of granulocytes. And so these basophils like eosinophils are also involved in allergic reactions. But the basophils are also really important for inflammation and the inflammation response during an infection. And so these basophils will produce a molecule known as histamine and this molecule histamine is going to be released during inflammation and it will promote inflammation by increasing capillary permeability or the permeability of the capillaries. And the permeability is how easily penetrable it is. And so uh this histamine molecule that is released by increasing capillary permeability, it will allow other defense cells to easily leave the bloodstream and enter into an infected area of the host so that they can help protect and defend the host. Now, mast cells are cells that are very similar in function to the basophils. However, the mass cells are going to be found inside of the tissues. And so they are going to be found in many different types of tissues rather than circulating through the blood, like what the basophils do. And so these mass cells uh are going to be capable of detecting tissue damage, de granulating to release histamine. And again, the histamine can then induce inflammation. And so uh the basophils uh are going to be very similar to the mass cells. Once again, the basophils are going to be in the blood vessels, uh basically uh circulating through the blood. And so over here, on this side of the image, we're showing you specifically the baso fill and the basophil is a granular site. So it's going to have these cytoplasmic Granules that stain a bluish purplish color and they contain histamine and so upon degranulation, releasing this histamine, uh the histamine once again can lead to inflammation. And so notice that the mass cells are going to be very similar to the basophils, except the mass cells are embedded in the tissues. And so you can see here the mass cells embedded in the tissues. And uh again, the mass cells are going to be able to detect specific types of antigens or allergens molecules that can cause allergies. And uh again, they can lead to degranulation and the release of histamine and the histamine can lead to inflammation. And so these basophils, again, they are important for allergic reactions and also important for the inflammation response. And so this year concludes our brief lesson on basophils and mass cells. And we'll be able to get some practice applying some of these concepts as we move forward in our course. And so I'll see you all in our next video.
6
Problem
Problem
Which of the following is a phagocytic cell found in the human body?
A
Eosinophil.
B
Neutrophil.
C
Basophil.
D
T cell.
7
Problem
Problem
Which of the following answers are characteristics or roles of granulocytes?
A
Release of hydrolytic enzymes that damage bacterial cell membranes.
B
Production and release of histamines which increases capillary permeability.
C
Release antimicrobial substances that damage the membranes of parasites.
D
Phagocytose invading microorganisms.
E
All of the above.
8
Problem
Problem
White blood cells are referred to as _________.
A
Platelets.
B
Erythrocytes.
C
Leukocytes.
D
Megakaryocytes.
9
Problem
Problem
Two immune cells have very similar functions. Both immune cells release histamine and induce inflammation. However, _________ cells reside in specific tissues, while _________ cells travel through the blood stream.
A
Mast cells; Basophil cells.
B
Basophil cells; Neutrophil cells.
C
Granulocyte cells; Basophil cells.
D
Eosinophil cells; Dendritic cells.
10
Problem
Problem
In type I allergic reactions, antibodies are produced and bind to:
A
Mast cells.
B
Neutrophils.
C
Eosinophils.
D
Monocytes.
11
Problem
Problem
Granulocytes:
A
Travel through the lymphatic system.
B
Are the most numerous leukocyte in circulation.
C
Develop in the thymus.
D
Do not contain distinct granules in their cytoplasm.
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