Chapter 11.3: Human Immune System

Table of Contents:

• Innate Immunity: Overview
• Innate Immunity: Inflammatory Responses
• Innate Immunity: Immune Cells and Molecules
• Innate Immunity: Complement System
• Adaptive Immunity: Overview
• Adaptive Immunity: B cells
• Adaptive Immunity: T cells
• Passive vs. Active Immunity
• Optional: Chapter 11.3 YouTube Video Playlist

Preview

The immune system is what protects us against the hostile microbes that we are in contact with everyday. It consists of a protective outer wall and a team of well-versed soldiers who fight together to protect their kingdom — our body.

Before we dive into this exciting battlefield, there are a few terminologies that we should familiarize ourselves with, which we will be using a lot throughout the chapters.

Pathogens:

• These are all kind of harmful microscopic enemies (virus, bacteria etc…) that can cause diseases.
• Many pathogens are bacterial in nature; common examples of diseases that are caused by bacteria include gonorrhea, tuberculosis, leprosy, and syphilis. Tuberculosis is a disease that often affects your lungs and can lead to death if left untreated; it is caused by the acid-fast bacterium Mycobacterium tuberculosis. Gonorrhea is a sexually transmitted disease (STD) that is caused by Neisseria gonorrhoeae. Syphilis is another STD; it is caused by Treponema pallidum.
• Viruses can also be considered pathogens. They can only reproduce by attaching themselves to hosts. When a virus enters the host’s body, it can take over the host cell’s machinery to replicate many copies of viral nucleic acid. Diseases caused by viruses include HIV, Corona, measles, AIDS, influenza, and herpes.