Med-Surg Immune System, Part 1: Intro, Innate Immunity, Inflammation

by Cathy Parkes

In this article, we give an overview of the topics in the immune system that you will need to know about for your Med-Surg and Critical Care classes. We also give you a refresher on how the immune system works, the two main types of immunity, and the inflammatory response. These topics are covered in our Medical-Surgical Flashcards (Immune system), and Cathy’s video follows along with the cards.

Med-Surg immune system topics

These are the topics that we will cover in the Immune System playlist for Med-Surg. These are the topics in the immune system that you should know for your exams!

  1. Innate vs. acquired immunity, inflammation
  2. Acquired immunity - humoral and cellular
  3. Immune system malfunction & infection
  4. Immune diagnostic tests: white blood cells, neutrophils, ESR, CRP
  5. Systemic lupus erythematosus
  6. Systemic sclerosis
  7. HIV/AIDs
  8. Cancer overview
  9. Tumor classification
  10. Chemotherapy, radiation, and complications (malnutrition, mucositis)
  11. More cancer treatment complications (neutropenia, anemia, thrombocytopenia)
  12. Skin and blood cancers
  13. Endometrial, cervical, ovarian and breast cancer
  14. Prostate, colorectal and lung cancer

What does the immune system do?

The overall function of the immune system is to protect the body from disease-causing microorganisms and keep you healthy.

Types of immunity

The actions that your immune system takes inside your body to protect you are known as the immune response. We divide the immune response into two categories: innate and acquired immunity. These categorizations differ in which antigens they respond to.

Antigens

Antigens are any substance that your immune system responds to and wants to get rid of. So, immunity acts against antigens, and antigens are things that your immune system reacts against.

This might seem like a circular definition, and it is. But you can think of it this way: the immune system is very smart, and it has three working rules:

  1. Substances with a different molecular makeup than that of your body are foreign
  2. Foreign substances are bad for you
  3. It needs to protect you against them

Innate immunity

Innate immunity is something that everybody is born with. These are defense mechanisms that help protect the body by acting against all antigens. It’s important to note innate immunity acts against all antigens, not just specific antigens.

Our innate immunity includes:

  • Skin — without skin, harmful microorganisms would just be directly jumping into our bloodstream and organs and we would be toast.
  • Stomach acid — we swallow bacteria all the time, but luckily our stomach acid neutralizes it so it’s harmless to us (most of the time)
  • Mucus — we also breathe in bacteria all the time, but luckily our mucus traps the bacteria and kills it
  • Phagocytic cells (usually white blood cells) — they also mobilize and kill bacteria

The inflammatory response

The inflammatory response is an important part of our innate immunity. Inflammation is your body’s protective reaction to injury, disease, or damage to tissues in your body. Inflammation happens in three stages:

  1. Warmth, erythema (redness), edema (swelling), decreased function or pain at the site of injury
  2. White blood cells kill off the microoganisms; dead tissue cells and exudate (fluid that’s a byproduct of the WBCs having killed bacteria, also known as pus) accumulate at the site of injury
  3. The damaged tissue is replaced by scar tissue

Acquired immunity

Acquired immunity is the process by which we produce antibodies against specific antigens, and we develop acquired immunity through the action of B and T cells. Acquired immunity can be cellular or humoral, and we will cover that in our next article.

Video on acquired immunity (cellular vs. humoral)

Cathy’s teaching on the immune system is intended to help prepare you for Medical-Surgical nursing exams. The Medical-Surgical Nursing video series is intended to help RN and PN nursing students study for nursing school exams, including the ATI, HESI and NCLEX.


Full Transcript

Hey, I'm Cathy. And in this video playlist, I will be covering the immune system. If you are following along with cards, I'm in the immune system section of our Medical-Surgical Nursing Edition 2.0 deck. And I will be following along with that deck.

However, you don't need to have this deck to get value out of this video series. And I just encourage you, if you don't have our deck, to make flashcards of your own because a lot of the information that you need to know as a nurse, it takes repetition to really get that information down.

So some of the items that I'll be covering in this playlist include the difference between innate and acquired immunity.

We'll be covering immune system malfunction.

We'll be talking about different disorders that relate to the immune system, including lupus, scleroderma, and HIV.

And then we will spend the remaining time talking about cancer. We'll talk about the risk factors, the signs and symptoms, the diagnostics for cancer, and treatment. And we'll definitely be covering nursing care of patients who have to undergo chemotherapy, radiation, etc.

In terms of the types of cancers that we will cover, we'll touch on a number of different cancers, but we will focus more on the most common types of cancers. So this includes skin, lung, prostate, breast and colorectal cancer.

So the overall function of the immune system is to protect the body from disease-causing microorganisms, and we do this through innate and acquired immunity.

Innate immunity is something that everybody is born with. These are defense mechanisms that help protect the body by acting immediately against all antigens. Okay? So not a specific antigen but against all antigens.

So some things that fall within innate immunity include our inflammatory response, which I'll talk about more here in just a minute. Our skin. So our skin is a barrier to prevent harmful microorganisms from entering our body. Our stomach acid. So if we were to swallow some bacteria, our stomach acid would hopefully burn that up and cook that so it can't hurt us. In addition, we have mucus which helps to trap pathogens so that we can't get infected, and phagocytic cells within the body. These are all things that all people have and work immediately against all antigens.

Then we have our acquired immunity. This is where we produce antibodies against specific antigens and we develop acquired immunity through the action of B and T cells. And we'll definitely go into more detail about those cells and the action of those cells in my next video.

But before we get into the details of acquired immunity, let's touch a little bit more on the inflammatory response, which is a key part of your innate immunity. So inflammation is your body's protective reaction to injury, disease, or damage to tissues in your body, and there are three stages to inflammation.

The first stage we would expect warmth; erythema, which is redness; edema, which is swelling; decreased function and/or pain at the site of injury.

During the second stage, white blood cells would kill off the microorganisms and exudate containing those white blood cells, as well as dead tissue cells would accumulate at the site of the injury.

And then during the third stage, the damaged tissue will be replaced by scar tissue.

Okay. So that is inflammation. When I come back with my next video, we will go into the details of acquired immunity. Thanks so much for watching!


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