The Lymphatic System

1. The Lymphatic System What Protects Our Bodies

2. Imagine this… ~ You are a knight in ancient medieval times. You are constantly on the look-out for enemy invaders. There! Suddenly, you spot one. You quickly inform the rest of your team as you go out to attack the enemy… ~ Now, what you just imagined happens everyday. Don’t believe us? Here’s a look inside your body.

3. The Immune System • A.K.A the Lymphatic System • What is it’s function? • Defends the body against germs, microorganisms, and other foreign invaders (A lot like a group of knights protecting a castle) • In most cases, it does a great job of keeping people healthy and preventing infections • Problems with the immune system can lead to allergies and deadly diseases

5. Main Types of Cells • T cells • Belongs to a group of white blood cells known as lymphocytes • Plays the central role of the immune response • The TCRs (T Cell Receptors) on the cell surface are responsible for recognizing antigens (any substance that produces antibodies) • B Cells • Belongs to a group of white blood cells known as lymphocytes • Vital part of the immune system • Proteins on cell’s outer surface, BCR (B Cell Receptors), allows cell to bind to a specific antigen

6. Organs of the Immune System

7. How the Immune System Relates to Other Systems

8. Stages of the Immune System OH NO!!! Intruders have gotten into the castle! What do we do?! Knights, to the front lines!

9. The Battle Plan

10. Stage 1 – The Battle Begins • Phagocytes (“Spies” of the immune system) constantly patrol throughout the body. • The goal is to identify any and all substances that can potentially be harmful to the body (also known as “scavengers” of the immune system) • First line of defense and try to immediately destroy invaders • However, they can’t destroy organic invaders (e.g. viruses, bacteria, fungi, protozoa…) • Macrophages mobilize lymphocytes (T cells which are first to activate immune response) • T cells, made in the thymus gland, start the battle

11. Stage 2 – Multiplied Forces • Additional forces begin to gather (B cells, specialized T cells) to ensure the effectiveness of the system • B cells can immobilize a virus or bacterium that moves freely in the blood, dying after disappearance of virus • “B-cell memory”, a second type of B-cell, doesn’t die but remains in bloodstream in order to respond faster to any external attack

12. Stage 3 – Final Attack & Victory • T cells destroy infected cells by chemically piercing the membrane and ensuring that content is lost • “Leakage” stops the replication cycle of the virus • Once the content of an infected cell is lost, antibodies neutralize the virus and stop it from invading other cells • When all invaders are destroyed, the war is won, and the surviving troops are finally recalled

13. Stage 4 – End of Hostilities • A third type of T cells, suppressor T cells (a.k.a. peacemakers) , take over • They release a substance that blocks the production of antibodies by B cells • Order the cease fire, stops all attacks • Memory T cells remain in the bloodstream and lymphatic system to allow faster response if a similar attack ever occurs again

14. Victory!!

15. The Battle is won, the knights have gone home, and the presentation has ended… Thank you all for being wonderful listeners!