All of the following are true of the second line of defense EXCEPT (A) increased production of h

All of the following are true of the second line of defense...

Key Concepts

Innate Immunity

Innate immunity is the body’s first, non-specific defense mechanism against pathogens. It includes physiological barriers and cellular responses that react quickly to eliminate invading organisms without prior exposure.

Second Line of Defense

The second line of defense comprises innate immune responses that activate when pathogens breach physical barriers. This includes processes like inflammation, the mobilization of phagocytes, and the release of chemical mediators to contain and eliminate the infection.

Inflammatory Response

The inflammatory response is a key component of the second line of defense. It involves increased blood flow, vascular permeability, and the release of mediators such as histamine, which recruit immune cells to the site of infection and help isolate and remove pathogens.

Phagocytosis

Phagocytosis is the process by which specialized immune cells, such as neutrophils and macrophages, engulf and destroy pathogens. This mechanism is fundamental to the second line of defense in eliminating foreign invaders.

Physical and Chemical Barriers

Physical and chemical barriers, like intact skin, mucous membranes, and substances such as stomach acid, form the first line of defense. These barriers serve as initial obstacles to infection, preventing pathogens from entering the body before innate immune responses are activated.

Transcript

0:00 Hi everybody.

00:01 So this question is asking about the second line of our non -specific immune defense mechanism.

00:08 And so in order to really understand the question, it's going to be useful to understand our entire non -specific immune defense system.

00:16 Now, the name of this system is pretty self -explanatory and that it's non -specific against defending different types of invading bacteria or viruses.

00:26 It doesn't differentiate between a virus or bacteria or any other type of pathogen, is only trying to prevent these pathogens from establishing an infection in our body in the first place.

00:39 And so you can divide the non -specific immune defense down into two other subcategories, the first line of defense, and as you might guess, the second line of defense.

00:50 Now, the first line defense consists of physical and chemical barriers that our body uses to prevent pathogens from getting in in the first place.

00:58 So a physical barrier, one really great example, is your skin, right? your skin is always preventing bacteria or other pathogens from getting into your body because it's a physical barrier between the outside world and the inside of your body.

01:14 One great example of a chemical barrier is the second line is your stomach acid.

01:22 Right so if you were to swallow a mouthful of food that had some sort of nasty virus in it it would go into your stomach and hopefully that virus would be killed off by the acid in your stomach and so that is a chemical protection or chemical first line defense that is part of your non -specific immune defense system one really good way that i like to think about first lines of defense is that they're always on right you don't have to turn them on.

01:55 You don't have to activate them.

01:57 Your skin is always going to be protecting you from invading pathogens, and your stomach ass is always going to be protecting you at the same time.

02:06 So you don't have to activate them.

02:08 They're always there.

02:09 They're kind of innately switched on.

02:12 One good analogy that i like to think of for the first line defense is that you have these pathogens that are all trying to invade your body, right? and your body is here on the other side.

02:23 The pathogens are on the left, and they're trying to get into the right side, which is your body to establish an infection.

02:31 And your first line defense is kind of like this wall or this barrier that's there, and it's preventing these pathogens from getting over the wall.

02:39 Now, no matter how good your first line defense is, you're always going to have some sort of bacteria or virus or other pathogen get over that.

02:47 And that's where your second line of non -specific immune defense comes in.

02:52 Your second line is a little bit more specific than your first line, because it has to be activated by the specific patterns or molecular patterns that are found on the outside of the invading pathogen.

03:06 And you can divide this into three different subcategories.

03:09 The first is the inflammatory response.

03:11 The second is phagocytes.

03:14 And the third are interferons.

03:16 Now, i know all of you at one point or another have experienced the inflammatory response.

03:23 If you've ever gotten a cut on your arm, it might swell up a little bit on the area around the cut...

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