Lecture 11: Innate Immunity Flashcards
What is the immune system composed of?
Cells, tissues, and organs that recognize foreign substances
distinguishes between ‘self’ and ‘non-self’ substances.
Define antigen.
Self and non-self substances that elicit an immune response (also called immunogens)
Antigens are crucial in the immune response.
What are the two branches of the immune response?
- Humoral Branch (B cells & antibody)
- Cell-Mediated Branch (T cells)
The branches differentiate between innate and acquired immunity.
What does innate immunity include?
- Physical Barriers
- Chemical Barriers
- Molecular Defenses
- Cellular Defenses
- Inflammation * Fever
Innate immunity is nonspecific and responds immediately to pathogens.
What is the role of skin in innate physical barriers?
The epidermis comprises tightly packed keratinocytes that produce keratin, creating a protective barrier
Skin is slightly acidic and salty which helps inhibit microbial growth.
What are mucous membranes and their function?
Architecture of columnar cells that form a protective barrier inhibiting penetration of microbes
ucus traps microbes and prevents adhesion.
What is peristalsis?
Smooth muscle contractions that propel microbes and food out of the gastrointestinal tract
This mechanism helps to eliminate pathogens effectively.
What is the function of lysozyme in sweat?
Antimicrobial enzyme that helps to kill bacteria
Lysozyme is also present in tears and saliva.
What is the complement system?
A system of 20 proteins (C1-C9) that activate in a cascade to enhance immune responses
Functions include opsonization, direct lysis of bacteria, and involvement in inflammation.
What are the major types of white blood cells (WBC)?
- Granulocytes
- Agranulocytes
Granulocytes contain toxic molecules, while agranulocytes do not.
What is phagocytosis?
The process by which phagocytes engulf other cells or materials
Key cells involved include macrophages, neutrophils, and dendritic cells.
What occurs during inflammation?
- Tissue injury introduces bacteria
- Chemical mediators are released
- Increased vascular permeability and vasodilation occur
- Neutrophils marginate and extravasate
This process is crucial for recruiting immune cells to the site of infection.
What is the normal body temperature range?
97-99.5ºF (36.1-37.5ºC)
Fever is typically defined as a temperature above 100.5ºF orally.
What are pyrogens?
Substances that cause fever
They can be exogenous (like LPS) or endogenous (like IL-1 from macrophages).
List the four major benefits of fever.
- Slows the growth rate of microbes
- Inactivates some bacterial toxins
- Increases immune system activity
- Forces a person to rest, conserving energy for fighting disease
Fever is a natural response to infection.
