N3 Anatomy and Physiology AY 2023-2024

1. Briefly describe the process of inflammation in an area that has been traumatized.

Inflammation is a nonspecific, defensive response of the immune system to protect the body from any infection, injury, or disease. Its goal is to locate and remove harmful substances from the body as well as damaged tissue components so that healing takes place. The inflammatory response includes the following stages:  

1. Vasodilation and Increased Blood Vessel Permeability 

• In this stage, the vasodilation of the arterioles dilates, letting more blood flow through the area of damage/injury. The increased permeability of the capillaries allows the defensive proteins (e.g. antibodies and clotting factors) to enter the site of injury. With these, it will result in the three signs and symptoms of inflammation: heat, redness, and swelling.

2. Emigration of Phagocytes

• The neutrophils will then adhere to the blood vessel endothelium's inner surface and push through the walls to the injured location. Monocytes will then follow the neutrophils and transform into wandering macrophages, which are big enough to engulf the damaged tissue, worn-out neutrophils, and invading microbes. The macrophages will die and after a few days, the pus formation occurs.  

3. Tissue Repair

• Lastly, the tissues will repair and restore itself until it goes back to totally normal.

2. Choose one type of Immunity (Innate and Humoral) and explain how its mechanism protects our body.

Innate Immunity

• Innate immunity includes both external and internal defenses: external physical and chemical barriers which are provided by our skin and mucous membranes, and internal defenses which includes antimicrobial substances and natural killer cells. 

1. First Line of Defense: Skin and Mucous Membranes

• The skin and mucous membranes provide both physical and chemical barriers which discourage the pathogens and other foreign substances to cause any disease or damage. This includes the following: 

1. The epidermis serves as a barrier from the entrance of microbes. 

2. The mucus produced by the mucous membranes traps mucous and foreign substances. 

3. The hairs and cilia that trap and filter microbes, dust, pollutants

4. The eyes’ lacrimal apparatus which produces and drains away the tears in response to irritants.

5. The saliva that washes microbes from the teeth and mouth’s mucous membrane. This helps in reducing the colonization of the mouth by microbes

6. The flow of urine which mitigates microbial colonization of the urinary system

7. The process of defecation and vomiting also help in washing away microbes

8. Sebum (oily substance produced by the skin), perspiration, and gastric juices also help in discouraging bacterial growth.  

2. Second Line of Defense: Internal Defenses

• When the pathogens are able to penetrate the first line of defense, they will then encounter a second line of defense. 

1. The interferons diffuse to uninfected neighboring cells to be able to synthesize antiviral proteins.

2. Complement system: Once the proteins are activated, they will improve certain immune responses.

3. The iron-binding proteins reduce the amount of available iron to inhibit the growth of certain bacteria.

4. Antimicrobial proteins (AMPs) kill microbes and attract dendritic and mast cells, which are active in immune responses. 

5. Natural killer cells kill infected body cells and certain tumor cells. 

6. Phagocytes ingest microbes and other substances. 

References

Tortora, G., & Derrickson, B. (2017). Principles of Anatomy & Physiology (15th ed.). Wiley & Sons.