Description

This video is part 1 of Innate Immunity – Classification and General Factors.

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All information in my immunology videos is sourced from:

• Book: Immunology, Eighth Edition by David Male, Jonathan Brostoff, David Roth, and Ivan Roitt
• Additional research: PubMed
• University lecture materials

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Difference between Innate and Acquired Immunity:

• Innate Immunity:
• Non-specific
• No immunological memory
• Attacks all agents equally
• Acquired Immunity:
• Specific defense
• Gains immunological memory

Classification of Innate Immunity:

1. General Factors:
• Barriers (Skin and Gastrointestinal tract)
• Pyrogenic reactions (Fever)
• Secretion
2. Cellular Factors:
• Microbiota
• Phagocytosis
• Natural Killer Cells
• Toll-like Receptors
• Inflammatory reaction
3. Humoral Factors:
• Complement System
• Interferons

General Factors:

• Skin:
• Physical barrier due to tight junctions
• Secretion of antimicrobial products
• Mucous Membranes:
• Contain antimicrobial substances such as lysozyme, pepsin, and defensins
• Low pH provides additional protection

Transcript

Introduction 0:00 hello and welcome to another video this 0:02 video is mainly going to be about the 0:03 innate immune system now your immune 0:06 system uses two main strategies to 0:08 defeat any type of unwanted invaders one 0:11 of the strategies is called the innate 0:12 immune system and the other ones called 0:14 acquired immune system the innate immune 0:16 system is mainly present since birth and 0:18 is therefore sometimes also called the 0:20 natural immune system 0:21 well they acquired however forms during 0:23 a person’s lifetime and is therefore 0:25 sometimes also called the adapted now 0:27 just remember that the baby also has 0:30 some type of acquired immune system I 0:31 just put the baby there to show you that 0:33 you’ve always had the innate immune 0:35 system ever since you were born so now 0:37 let’s put this to practice imagine we 0:39 have three different types of bacteria 0:40 right the innate immune system is what 0:43 we call nonspecific because it actually 0:46 works against any type of agents equally 0:48 the adaptive however works very specific 0:52 as you see right here and not only that 0:55 upon defeating the bacteria you gain 0:57 some kind of immunological memory which 0:59 usually becomes enhanced upon repeated 1:02 exposure to the same agents the innate 1:05 immunity doesn’t really have that as 1:06 well let’s see how that works we mainly Classification of the Innate Immune System 1:09 classify the immune system into three 1:11 different types the first is well called 1:13 general factors and we’ve got the 1:15 cellular factors and also have the 1:17 humoral factors the general factors 1:20 include physiological barriers at the 1:23 portal of entry like the skin and the 1:25 mucous membranes and they’re usually 1:28 analogically enough the first line of 1:30 defense next we have the para genetic 1:33 reactions now don’t get scared if you 1:34 haven’t heard this term before I’ll get 1:36 more into this later on talk about the 1:38 macrophages mainly but pyrogenic 1:41 reactions often refer to as fever some 1:45 viruses and bacterias cannot really 1:47 replicate optimally because the body 1:49 changes its temperature so that’s why we 1:52 call it the general factors because it 1:55 works generally by increasing the 1:56 temperature another general factors are 2:00 secretion inab secretion of different 2:02 enzymes fatty acids the cellular factors 2:05 we got your own microbiota fighting for 2:07 space and food the phagocytosis by cells 2:11 like neutrophils and macrophages 2:13 they do that by the different receptors 2:16 they have in the surface I also got 2:18 natural killer cells so they’re really 2:19 important for the antiviral immune 2:21 response these cells can bind to surface 2:25 of antigens by using toll-like receptors 2:27 which usually to inflammatory response 2:30 you also get humoral factors which 2:32 include the complement system at the 2:34 interference now I know this seems a lot 2:36 but trust me it all gets logical once 2:39 you understand the concept in my opinion 2:41 if you want to learn immunology properly 2:43 you need to understand different parts 2:46 individually before you can understand 2:49 the whole concept together in in system 2:51 and that’s what I’m aiming to show you 2:54 everything individually first and then 2:56 put them all together and show you have 2:58 this wort in the system alright so in General Factors of Innate Immunity 3:01 this video I’m mainly gonna focus on the 3:02 general factors because those are really 3:04 important factors to start with when you 3:06 want to understand immunology now 3:08 imagine these are your epithelial cells 3:12 let’s say this is your skin for example 3:14 the first one includes physical barrier 3:17 where bacteria cannot really enter 3:19 because of the tight junctions these 3:21 cells really have another mechanism is 3:24 when the bacteria can’t enter cause of 3:26 secreted products could be free fatty 3:28 acids released biogas the intestinal 3:30 tract or enzymes released at the mucous 3:33 membrane so let’s do it like that in the 3:36 saliva sweat glands and tears we have 3:39 something called lysozyme which when 3:41 secreted out they break down the 3:43 peptidoglycan layer of the bacterial 3:45 cell wall next you know the 3:47 gastrointestinal tract you got some 3:48 cells in the walls of your stomach 3:50 called para toll and chief cells chief 3:53 cells can release pepsin which breaks 3:55 down the proteins of certain bacteria 3:58 and partly tell cells namely release 4:00 hydrochloric acid for lowering the pH we 4:04 can also have defensins in the gues 4:05 intestine tract and the list goes on 4:07 the point is that we secrete out quite a 4:11 lot of substances as a part of our 4:13 general innate immunity some bacterias 4:16 can actually get through all of this 4:18 mess without even getting hurt and those 4:20 other bacterias that usually makes us 4:23 sick all right so what else do we have 4:25 you know the normal microbiota you have 4:28 in your body they actually protect you 4:30 by making a hard environment for the 4:31 foreign bacteria to grow in by taking up 4:34 space and food for example 4:35 so that’s namely the general factors I 4:39 wanted to talk about now from the 4:42 cellular factors we’ve already talked 4:43 about the microbiota limiting the 4:45 pathogenic bacteria from growing in my 4:48 next video we will look at what taller 4:50 receptors are and how phagocytosis 4:53 happens in details and steps in 4:55 inflammation natural killer cells has a 4:58 cytotoxic mechanism and I feel like it’s 5:01 more logical to talk about it later when 5:03 I talk about the cellular immune 5:04 response as it kind of fits more there 5:06 all right so let’s look at these