Exploring the Immune System Line of Defense: 3 Key Strategies
There’s nothing worse than feeling a tinge of discomfort in your throat alerting you that something’s not quite right. When it’s accompanied by a sudden bout of sneezes or a slight fever, you know that it’s time to accept the inevitable: A pathogen has staked its claim in your body, and you’re officially getting sick.
Long before you feel that first tickle, however, your immune system is already hard at work fighting the good fight against the pathogens causing those symptoms.
The immune system has multiple lines of defense designed to help you maintain a clean bill of health, but it’s not an exact science. Occasional illnesses are a part of life, even with a healthy immune system.
Today, we’re dissecting the three strategies the immune system has in place to keep unwanted illnesses at bay.
What Is the Immune System?
When you think of your immune system, what do you see? A tiny but mighty army defending its fortress (a.k.a. you)? You’re not wrong! The immune system is our body’s first wall of defense when we encounter antigens and pathogens attempting to nonchalantly sneak past those defenses.
The immune system is composed of specialized cells that work to identify and eliminate invaders. Like an army, our immune systems use multiple layers of defense to keep those pathogens at bay.
The Immune System’s Three Lines of Defense
What are the three lines of defense in the immune system? And are they akin to defensive tiers in football, where the first line of defense represents the biggest and best and the second and third lines act as backup?
Not quite.
While each line of defense plays a vital role in the immune system’s function, one isn’t inherently more important than the others. Although certain defenses may be more effective against specific pathogens in specific situations, they all collaborate to shield your body from harmful invaders to ensure your well-being.
Below, we break down your immune system’s three primary lines of defense, exploring what makes each one unique and how they work to effectively keep your body safe against pathogens, such as viruses and bacteria.
#1 Physical Barriers
When a pathogen tries to enter your body, the first line of defense it’s up against is our external physical barriers, such as our skin, sweat, saliva and tears. These barriers offer a basic yet effective barrier of protection against unwanted microorganisms.
Other physical barriers include:
- Mucous membranes
These slimy membranes line our nose, throat, intestines and reproductive tract and trap microbes we come into contact with as we breathe and eat.
- Nasal hairs
The hairs inside your nasal cavity have more responsibilities than causing the occasional sneeze. They also trap pathogens and environmental pollutants, such as pollen and dust (hence the sneezing).
- Acidic fluids
Urine, gastric juices and vaginal secretions create low pH conditions, which aren’t hospitable for pathogens and often destroy them.
#2 Innate Immune System
When pathogens bypass the physical barriers, they come across our bodies’ second line of defense: the innate immune system. Rather than targeting particular pathogens, this defense provides an immediate response to any pathogens it detects. Using phagocytes, a broad type of white blood cell, the innate immune system engulfs, digests and eliminates pathogens as they wander through your body.
#3 Adaptive Immune System
While slower acting than the innate immune system, the final line of defense—the adaptive immune system— often defends your body with more precision. It works by using memory cells that target germs you’ve encountered previously, thus providing a quick response upon being re-exposed.
The adaptive immune system is why we usually get certain illnesses, like chicken pox, just once in our lives. After fighting off the virus, our bodies build a natural immunity to it, recognizing it the next time our bodies come into contact with it and destroying it on site.
The adaptive immune response begins with dendritic cells, which capture and present fragments of the pathogen to helper T cells in nearby lymph nodes. The helper T cells send signals to other immune cells known as B cells, telling them to produce the antibodies that will target the invading pathogen. This creates memory cells that can recognize and neutralize the threat if you’re re-exposed to it.
The University of Florida: Your Pathway to Success
While each line of defense may be referred to as first, second and third, they all play crucial roles in maintaining our body’s health against COVID-19, the flu, the common cold and other viruses.
Understanding the importance of these defenses can inspire individuals to pursue careers in immunology and related fields. If you’re interested in developing vaccines or becoming involved in cutting-edge medical research, the University of Florida offers several online graduate programs tailored to help you achieve your professional goals:
- Master’s Degree in Medical Physiology and Pharmacology
- Master’s Degree in Medical Physiology and Aging
- Graduate Certificate in Medical Physiology
- Graduate Certificate in Medical Physiology with a specialization in Cardiovascular/Renal Physiology
All of our programs offer online students the following advantages:
- Asynchronous classes that allow you to complete your coursework on your schedule
- Year-round start dates
- No GRE requirements
- Affordable tuition costs
- A renowned education from U.S. News’ top 10 public universities in the nation
Discover the program that aligns with your passions, and start your application today!
Sources:
https://www.news-medical.net/health/What-are-the-Three-Lines-of-Defense.aspx
https://www.ncbi.nlm.nih.gov/books/NBK279396/