The Body's Defense

Introduction

In this section, you'll review how bodies protect themselves from pathogens. Protections include inflammatory responses, the immune system, and standard precautions.

 

The human body is designed with many protective features to help keep pathogens from getting in. These are just a few examples of some of its defenses.

• The skin is the body's first line of defense. It is not only the largest organ, but also a major factor in keeping pathogens out. As long as the skin is intact, the body can keep many pathogens out.
• Eyelashes and eyebrows help protect the eyes from pathogens.
• Cilia help trap pathogens that may try to enter through the respiratory system.
• Tears, mucus, saliva, and other body secretions help to trap, cleanse, and remove pathogens and debris from the body.

 

Inflammatory Response

Inflammation is the body's way of responding and fighting when it's invaded by a pathogen or injured through trauma. Inflammation can occur with any threat or injury to the body. If a pathogen is present, the body has specific steps that it goes through to mount an immune response against the pathogen. Inflammation has specific signs and symptoms:

• Redness
• Heat
• Swelling
• Pain 

These signs and symptoms can vary from being very mild to moderate to severe.

 

If the inflammatory response isn't effective, then the immune response is the body's next step to fight pathogens. Below are indications that the inflammatory response isn't enough to get rid of the pathogen:

• Accumulation of purulent drainage (pus)
• Fever
• Lymph node enlargement
• Septicemia, an infection that occurs when the pathogens have entered the bloodstream
• Septicemia requires immediate antibiotic therapy.

 

Immune System

The purpose of the immune system is to protect against pathogens and abnormal cell growth. There are two types of immune responses that can occur:

• Cell-mediated immunity is usually involved in attacking and fighting viruses, fungi, cancer cells, and organ transplants.
• Humoral immunity produces antibodies that are capable of killing microorganisms and recognizing the same pathogen in the future. This type of immunity is part of how vaccinations work in our bodies.

There are four general phases that occur in both types of immunity:

1. Recognition of the invader

2. Growth of T cells and B cells

3. T cells and B cells mount attack against the pathogen

4. A slowdown of the immune system after the death of the pathogen

 

Standard Precautions

The Centers for Disease Control and Prevention (CDC) spent many years studying and revising precautions that should be taken by all healthcare providers who have direct contact with patients.

Standard precautions are the minimum infection prevention practices that apply to all patient care, regardless of infection status of the patient.

All direct care workers in the medical field need to follow the standard precautions.

Standard precautions include the following:

• Hand hygiene
• Use of personal protective equipment, or PPE (gloves, gowns, masks)
• Safe injection practices
• Safe handling of potentially contaminated equipment or surfaces in the patient environment
• Respiratory hygiene/cough etiquette

For standard precautions to be effective, they must be practiced at all times when working with patients. The healthcare worker assumes that every patient is potentially infectious when providing patient care. In the next section, you'll look at how exposure can occur and what can be done to prevent it.

 

Key Points

• The human body has many protective features to keep the pathogens from entering, including skin, eyelashes, and cilia.
• Inflammation is the body's way of responding and fighting when it's invaded by a pathogen or injured by trauma. Signs and symptoms are redness, heat, swelling, and pain.
• The purpose of the immune system is to protect against pathogens and abnormal cell growth.
• Standard precautions are the minimum infection-prevention practices that apply to all patient care.