immune+system+notes+kr

=Immune System Notes=

Keaton Rye
A pathogen is a human infectious disease that are caused by bacteria and viruses.
 * 1. What is a pathogen?**


 * 2. What are the body's three lines of defense against pathogens?**
 * 1) Barriers
 * 2) First responders,
 * 3) Specific defenses

Bacteria are single celled prokaryotes. The do not have a nucleus. Bacteria have a cell wall that is made of amino acids. The walls of of some bacteria are surrounded by a sticky thing that allows them to stick to things... Theis sticky barrier also provides defense. The bacteria can move freely throughout the body.
 * 3. Write a one paragraph summary of bacteria.**

Viruses are unquie because they are not living or dead. A virus reproduces using the cells inside a body. Without the cells the virus appears dead. A virus has two parts: an outer capsid composed of protein units and an inner core of nucleic acid. The virus enter the system and lock into and kill the cells. Viruses are the cause of many illnesses. The cannot be cured, just treated.
 * 4. Write a one paragraph summary of viruses.**

it is a virus that has not been to one place before. One theory is that viruses can come form comets. And the dust from the comets infects birds first and then the virus evolved into where it can be infected from human to human.
 * 5. What is an emerging virus?**

=IMMUNE SYSTEM= An antibody is a protein produced in response to the presence of an antigen.
 * 6. What is an antibody? What do they do?**

A B Cell produces plasma cells and memory cells.
 * 7. What is B Cell?**

Kills virus infected cells
 * 8. What is a Cytotoxic T Cell?**

it regulates immunity.
 * 9. What is a Helper T Cell?**

An antigen is a foreign substance, which mostly is a protein
 * 10. What is an antigen? How does the body respond to an antigen?**