Introduction to the Complement System - Video Tutorials & Practice Problems
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Introduction to the Complement System
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in this video, we're going to begin our introduction to the complement system. And so the complement system is really just a system of inactive proteins that are found circulating in our blood and in our tissues. And they are capable of initiating an immune response when these inactive complement system proteins become activated by an infection. And so once again, these compliments system proteins start off as inactive proteins, but upon signals of microbes during an infection, those inactive proteins can become activated proteins and the activated complement system proteins will lead to a cascade of several different reactions that ultimately generate some kind of immune response. And the immune response that can be triggered by activation of the complement system includes removal of invading microbes and inflammation, which can also help to eliminate microbes. Now it is important to note that the complement system is not adaptable, which means that the complement system does not change or adapt over time through exposures to different microbes, which means that the complement system is not part of adaptive immunity. Uh and so the complement system instead is considered part of innate immunity. And it is important to note that however, although the complement system is part of innate immunity, it does complement or act in combination with antibodies uh and with the antibody response of adaptive immunity. And so this complement system, although it is part of innate immunity, it does complement or act in combination with adaptive immunity. And so that is an important feature to keep in mind. Now the complement system once again consists of these inactive proteins and uh the complement system proteins can be activated by one of three different pathways that we refer to as the alternative pathway collecting pathway and the classical pathway. And so if we take a look at our image down below notice we're showing you our map of the lesson on innate immunity and we've already talked about the first line defenses and we know that we've talked about the second line of defense and cells of immunity and uh we've talked about scanning systems including cell communication and pattern recognition receptors. So here in this video we're four focusing specifically on the complement system and the complement system proteins again are inactive proteins that can be activated by one of three different pathways, the alternative pathway, the lectern pathway and the classical pathway. Now it turns out that it's this classical pathway over here that is going to complement adaptive immunity and so notice that it does utilize antibodies and we'll get to talk a lot more about each of these three different types of complement system activation pathways as we move forward in our course. Now, another thing that's important to note is that the complement system because it consists of these inactive proteins uh it does serve somewhat as a scanning system. So it is going to be important for sensing and detecting signs of microbes. However, upon activation of the complement system proteins, those complement system proteins can trigger innate effect er action such as for example, to go psychosis and inflammation. And so the complement system we're saying here can promote or promotes fake acidosis and inflammation, and we'll be able to talk more about this idea as we move forward in our course. But for now this here concludes our brief introduction to the complement system and we'll be able to learn a lot more about the complement system as we move forward in our course. So I'll see you all in our next video.
2
Problem
Problem
What does the word 'complement' mean in the name complement system?
A
This is a system of proteins that complements or enhances the abilities of the immune system to kill microbes.
B
This is a system of proteins that replaces the innate immune system when the infection is too extreme.
C
This is a system of proteins that competes with the adaptive immune system to kill pathogens.
3
Problem
Problem
Which of the following are results of activation of the complement system?
1. Removal or destruction of microbes. 2. Inflammation. 3. Production of antibodies.
A
2 only.
B
1 and 2.
C
3 only.
D
1, 2, and 3.
4
concept
Proteins of the Complement System
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4m
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in this video, we're going to briefly talk about the proteins of the complement system. And so the complement system proteins are all designated with a letter C. And they are numbered C one through C nine. In terms of the order of their discovery where C one was discovered first and C nine was discovered last now these complement system proteins once again they remain inactive and so they circulate through our blood and in our tissues as they're inactive forms until these complement system proteins are fragmented. And once these complement system proteins are fragmented, they become activated and the activated fragments are indicated by lower case letters, such as for example, the lower case letter A and the lower case letter B. Now the complement system protein C3 is a very important in a very critical complement system protein. And once again, these complement system proteins are going to exist in their inactive forms. and so C3 is a critical inactive complement system protein And the C3, complement system protein can become activated by the activity of an enzyme called C3 converts. And so C three converts is an enzyme that will activate C three by hydra. Lies ng or fragmenting C three into the C three A & C three B fragments. And so the C3 A and C3B fragments which are active, can interact with other complement system components, ultimately causing some kind of immune response. And recall that the immune responses of complement system activation include optimization, sell license and inflammation all which we'll get to talk more about as we move forward in our course. And so if we take a look at our image down below, notice what we're showing you here at the top is the enzyme C three converts, Which is being represented here as this pair of scissors because its function is to end cinematically cleave or fragment C3. And so notice here we have the complement system, protein C3 right in the middle. And C three converts is an enzyme that will cleave or fragment C three into the activated activated fragment C. Three A and C three B. And so C three A and C three B. Through a cascade of reactions can ultimately lead to these immune responses such as for example, C three A can lead to inflammation and inflammation is an innate immune response that can help to eliminate microbes and we'll get to talk a lot more details about inflammation later in our course. Uh and C3B can lead to a process known as optimization, which we'll get to talk more about moving forward in our course as well, but it helps to improve Figo psychosis and it can also lead to sell like ISIS. And so here we're showing you a microbe that is being LISZT And so ultimately what we're saying here is that these proteins of the complement system need to become activated and upon activation they can lead to immune responses such as inflammation and optimization or sell license. And so this year concludes our brief lesson on the proteins of the complement system, and we'll be able to learn more about the complement system as we continue to move forward. So I'll see you all in our next video.
5
Problem
Problem
If the complement proteins are always present in the body, then why are the results of the complement system not always occurring?
A
The complement system proteins need to be activated by the invasion of a microbe.
B
The complement system proteins are held in the lymph nodes until an infection occurs.
C
The complement system proteins are inactive until cleaved by another complement protein.
D
The complement system proteins are not always present and only translated when an infection occurs.
E
A and B.
F
A and C.
G
D only.
6
Problem
Problem
Place the steps of the complement system in the correct order (Order steps 1-3).
_____ Opsonization, cell lysis of microbes, or inflammation occurs.
_____ C3 convertase splits C3 into C3a and C3b.
_____ C3a and C3b recruit other complement proteins to create an immune response.
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2m
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7
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Map of the Lesson on the Complement System
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3m
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in this video, we're going to introduce our map of the lesson on the complement system, which is down below right here and so we can go ahead and label the title of this map the complement system. Now activation of the complement system can actually be initiated by one of three different pathways which are the alternative pathway, the lectern pathway or the classical pathway. Now, each of these three different pathways does differ in the initiation of how they go about activating the complement system. However, although they differ in the initiation, all three pathways end up resulting in the formation of the Enzyme C3 converts. And recall from our last lesson video that C three converters is an enzyme that is capable of activating the complement protein, C three by fragmenting it into C three A and C three B. And of course we know that C three convert. These can end up resulting in three possible effects, or three possible immune responses which are optimization sell license of the invading microbe or the inflammatory response leading to inflammation. And so as we move forward in our course, we're going to talk about these three different pathways that activate the complement system. And we'll also get to talk about these three effects that can result from activation of the complement system. And so if we take a look at our image down below, notice that the complement system again consists of these inactive proteins that circulate in the blood and in our tissues and these inactive complement system proteins can become activated through one of three different pathways. The alternative pathway, the electron pathway, or the classical pathway. Now notice that the classical pathway here has this little asterix, because the classical pathway is the one that complements the adaptive immunity. And so the classical pathway is going to utilize antibodies which helps it complement the adaptive immunity. Now notice that all three of these pathways, alternative leptin and classical pathways. They all differ in how they initiate activation of the complement system. However, notice that all three pathways converge eventually at the formation of this enzyme C three convert these and we know from our last lesson video once again that C three converters will end automatically, cleave C three into C three a.m. C three B, which can ultimately lead to these three immune responses, optimization or improved fabio psychosis, microbe cell ISIS or the inflammatory response. And so those are the effects of activation of the complement system. Now, this year again concludes our map of the lesson on the complement system. But as we move forward, we're going to talk more details about all of these different things that you see here. So I'll see you all in our next video
8
Problem
Problem
How do the three pathways of the complement system differ?
A
The pathways differ in the resulting immune response they trigger.
B
The pathways differ in the complement proteins that they activate.
C
The pathways differ in what triggers the initiation of the pathway.
9
Problem
Problem
The possible effects of the lectin pathway of the complement system are?
