Infectious Diseases and the Immune System

Study Notes

Infectious diseases are caused by the presence of a living thing within the body.
Pathogens enter the body and cause harm, resulting in an infectious disease.

Pathogens require food, a place to live, and a way to reproduce.
The human body can sometimes provide these necessities for pathogens.
Pathogens can spread through various means:
- Contact with another person
- Contaminated objects
- Animal bites
- The environment (e.g., soil, water)

The immune system is responsible for defending the body against pathogens.
It distinguishes between different types of pathogens and reacts accordingly.
There are three lines of defense within the immune system:
- First line of defense: Physical and chemical barriers like skin, mucous membranes, cilia, and chemicals in saliva and stomach acid.
- Second line of defense: Triggers inflammatory response and leukocyte response, leading to the activation of phagocytes to destroy pathogens.
- Third line of defense: Specific immune system involving lymphocytes (T and B cells) that target specific pathogens.

A test panel that provides information about the cells in a patient's blood.
Measures the concentration of white blood cells, red blood cells, and platelets.
It can be ordered to diagnose and determine the severity of disorders affecting blood cells, especially when symptoms like fatigue, weakness, infection, inflammation, bruising, or bleeding are present.