The Lymphatic System What Protects Our Bodies
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.
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
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
Stages of the Immune System OH NO!!! Intruders have gotten into the castle! What do we do?! Knights, to the front lines!
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
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
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
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
The Battle is won, the knights have gone home, and the presentation has ended… Thank you all for being wonderful listeners!