Host Defense Barriers Quiz

Physical Barriers to Pathogen Invasion

• Sweat is a physical barrier to pathogen invasion.

Function of Sebum in Host Defense

• Sebum has antibacterial properties, helping to prevent pathogen invasion.

Function of Lacrimal Apparatus in Host Defense

• The lacrimal apparatus helps to flush out pathogens from the eyes.

Inhibition of Microbe Growth through Acid pH

• Gastric juice, with a pH range of 1.5-3.5, contributes to inhibiting microbe growth through acid pH.

Role of Vomiting and Diarrhea in Host Defense

• Vomiting and diarrhea help to eliminate pathogens from the body.

Chemical Factors in Host Defense

• Lysozyme is a chemical factor involved in host defense.

Microbial Antagonism by Normal Microbiota

• Competition for resources is a mechanism of microbial antagonism by normal microbiota.

Staphylococcus Epidermidis

• Staphylococcus epidermidis is a normal resident of the skin.

Immunity Structure

• Innate immunity, which includes skin, mucous membrane, and normal microbiota as the first line of defense, provides immediate defense against infection.
• Adaptive immunity, which involves the production of specific antibodies to destroy antigens, provides long-term protection against infection.

Cells and Organs Involved in Immunity Structure

• The second line of defense in immunity structure involves cells and organs such as neutrophils, macrophages, and dendritic cells.

Function of Natural Killer (NK) Cells

• Natural Killer (NK) cells help to destroy infected cells and tumor cells.

Nonspecific Defense (Innate Immunity)

• Nonspecific defense, or innate immunity, provides immediate defense against infection and is non-specific to particular pathogens.

Passive Immunity

• Passive immunity provides temporary protection against infection, often through the transfer of antibodies from another individual.

Cellular Substances Involved in Immunity Structure

• Cellular substances such as complement proteins and interferons are involved in the second line of defense in immunity structure.

Leukocytes

• Leukocytes are derived from pluripotent stem cells in the bone marrow.
• Basophils are a type of leukocyte that release histamine and are related to allergic reactions.
• Eosinophils are a type of leukocyte that occur in large numbers during allergy reactions and worm infections, and help detoxify foreign substances.
• Lymphocytes are a type of agranulocyte that circulate in the blood and are found in large numbers in lymph nodes, spleen, thymus, and tonsils.

Functions of Dendritic Cells

• Dendritic cells help to present antigens to other immune cells, activating an immune response.

Chemotaxis

• Neutrophils are involved in the process of chemotaxis, moving towards the site of infection.

Phagocytic Cells

• Macrophages and neutrophils are types of cells that eat or engulf other substances, patrol the body, and destroy dead cells and cellular debris.

Test your knowledge on the fundamentals of host defense barriers, including natural host resistance, infection site and tissue specificity, and physical and chemical barriers to infection. This quiz covers the first line of defense, including physical barriers such as skin and mucous membranes.