Resistance to disease Flashcards
What is disease resistance?
The body’s ability to destroy or deactivate pathogens and foreign agents through defense mechanisms.
Example: The immune system fights off bacteria and viruses to prevent illness.
What is disease susceptibility?
The lack of disease resistance and increased risk of acquiring disease.
Additional information: Individuals with compromised immune systems are more susceptible to infections.
What are the two main defense mechanisms?
Nonspecific and specific defense mechanisms.
Example: Nonspecific defenses target all pathogens, while specific defenses target specific pathogens.
What do nonspecific defense mechanisms target?
All pathogens and foreign agents.
Additional information: Nonspecific defenses include barriers, cellular responses, and inflammation.
What are examples of physical and chemical barriers?
Intact unbroken skin, mucosa, sweat, sebum, cilia, sticky mucus, cerumen, hair, saliva, tears, nasal secretions, and vaginal secretions.
Example: Skin glands secrete sweat and sebum to create a hostile environment for pathogens.
What enzyme is found in saliva, tears, and nasal secretions with antibacterial properties?
Lysozyme.
Example: Lysozyme helps to destroy bacterial cell walls.
What are cellular responses?
Cellular responses are the body’s second line of defense and are activated when microorganisms penetrate the body’s first line of barrier defenses. Cellular responses include reactions from immune cells, nonimmune cells, and plasma proteins.
What do some WBCs do to destroy microorganisms?
Some WBCs destroy microorganisms through phagocytosis. The primary phagocytic cells are neutrophils and macrophages.
What are cytokines?
Some cells release cytokines, small proteins that control the immunologic and inflammatory responses of other cells. Some cytokines accelerate these responses and others slow down or reverse them, especially when they are out of control. Other cytokines recruit phagocytic cells to increase their numbers. Examples of cytokines are interleukins and interferons, the latter of which fight viral infections.
What are complement proteins?
Cellular responses also include antigens found in blood plasma, called complementary proteins. These “complement” the ability of other cells to destroy pathogens and combat infection. Some antigens mark pathogens by coating them so antibodies can locate and destroy them later. Other antigens bore holes into pathogens such as bacteria, so their cell contents leak out, causing them to perish.
What is inflammation?
Inflammation is a protective response to tissue damage resulting from a variety of causes, including infection and trauma. The purpose of inflammation is to eliminate pathogens and foreign agents, remove damaged tissue, and prepare the area for repair. Inflammation can be classified by its extent as local or systemic, or by its duration as acute or chronic.
What do saliva, tears, and nasal secretions contain?
Lysozyme
An enzyme with antibacterial properties
What are the primary phagocytic cells?
Neutrophils and macrophages
The primary phagocytic cells are neutrophils and macrophages.
What is local (acute) inflammation?
Inflammation confined to a specific area. Characteristics include swelling, heat, a loss of function, redness, and pain.
Acute inflammation is usually of short duration, lasting approximately 72 hours (3 days) after initial onset, but can last up to 5 days.
What are the characteristics of acute inflammation?
Swelling, heat, a loss of function, redness, and pain.
Cytokines facilitate inflammation by promoting vasodilation, capillary permeability, and clotting mechanisms.
What is subacute inflammation?
Inflammation that can occur after acute inflammation, characterized by swelling and pain but lacks heat and redness.
Subacute inflammation usually begins on day 4 and may last 2 to 6 weeks.
