Immunity Lecture 9

Study Notes

Immunity is the body's defense against infectious organisms and other invaders through the immune response
The immune system is composed of special cells, proteins, tissues, and organs that defend against invaders and maintain health

Non-specific (Innate) Immunity: acts against all invaders and is not specific to a certain group of micro-organisms
Specific (Acquired) Immunity: develops during lifetime as a result of exposure to antigens and involves production of antibodies and specialized lymphocytes against specific antigens

Skin is the first barrier and mechanism of non-specific defense
Epithelial surfaces form a physical barrier that is impermeable to most infectious agents
Sebaceous glands in the dermis provide an environment unsuitable for microbe survival
Sweat glands secrete sweat that washes off infections and has a high salt content that dries microorganisms
Flushing action of tears and saliva helps prevent infection of the eyes and mouth
Saliva contains anti-bacterial properties due to lysozymes
Movement due to peristalsis or cilia in the gastrointestinal and respiratory tract helps remove infectious agents
Gut flora can prevent pathogenic bacteria colonization by secreting toxic substances

Found in two types: Naturally Acquired Immunity and Artificially Acquired Immunity
Two mechanisms of adaptive immunity:
- Humeral Immunity: involves cellular macromolecules in body fluids, targeting extracellular pathogens like bacteria
- Cellular Immunity: involves activation of phagocytes, T-lymphocytes, and release of cytokines, targeting microbes that survive inside cells, such as viruses, fungi, protozoans, cancers, and intracellular bacteria, and plays a role in transplant rejection