Answer the following questions:
1. Briefly describe the process of inflammation in an area that has been traumatized.
A. Histamine release and the reaction to histamine
- As soon as an injury occurs, histamine is released from the mast cells of the connective tissues, basophils, and platelets.
- Two immediate changes occur in the blood vessels as a response to histamine: Increased permeability and vasodilation.
B. Clotting
- Increase in the capillaries’ permeability causes leakage of clotting proteins into the tissue.
- Fibrinogen is then converted into a thick network of fibrin threads, which trap and isolate invading organisms and prevents the spread of their harmful toxins.
- Increased permeability allows substances that are usually retained in blood to pass out and permits defensive substances such as antibodies and clot-forming chemicals to enter the injured area from the blood.
- Vasodilation allows more blood to flow into the damaged area by increasing the diameter of the blood vessels. This also helps in removing microbial toxins and dead cells.
C. Phagocytes
- Shortly after the inflammatory process starts, phagocytes are attracted to the site of the injury through chemotaxis.
- Neutrophils begin to emigrate through the walls of the blood vessel and predominate in the early stages of the infection. They will eventually die off rapidly together with the microbes that they ate.
- Monocytes arrive at the tissue within a few hours and turn into macrophages.
- These macrophages wander along the site and engulf damaged tissue, worn-out neutrophils, and invading microbes.
D. Formation of pus and healing
- Within a few days after the death of macrophages, a pocket of dead phagocytes and damaged tissue forms. This collection of dead cells and fluids is called “pus”.
- Once the infection is terminated, the pus is gradually destroyed over a period of days and is absorbed.
2. Choose one type of Immunity (Innate and Humoral) and explain how its mechanism protects our body.
Innate immunity, also known as nonspecific immunity, is the defense system that a person is born with. It protects the body against all antigens and the barriers that this defense system provides prevent harmful materials from entering the body.
This type of immunity defense includes the first and second lines of defense.
The first line of defense
- Skin and Mucous Membranes.
- Serves as both physical and chemical barriers to pathogens and foreign substances.
The second line of defense
- Internal Defenses such as antimicrobial substances, natural killer cells, phagocytes, inflammation, and fever.
- Any pathogen that gets through the surface encounters the second line of defense.