Immunity and Organs

Study Notes

Differentiates between SELF and NON-SELF entities.
Classifies non-self entities into infectious (pathogens: viruses, bacteria, fungi, parasites) and non-infectious (food, pollen, dust).
Recognizes infectious self (cancer) and non-infectious self (body cells and proteins).

Identification: Distinguishes non-infectious self and infectious non-self.
Recruitment: Mobilizes immune effectors.
Elimination: Clears pathogens from the body.
Prevent Recurrence: Establishes immunological memory to prevent future infections.
Deactivation: Stops immune response to prevent collateral damage.

Innate Immunity: Non-specific response, immediate maximal reaction, no immunological memory.
Adaptive Immunity: Specific response, delayed maximal reaction, leads to immunological memory.
Humoral Immunity: Mediated by macromolecules in body fluids.
Cellular Immunity: Involves activation of phagocytes, T-lymphocytes, and cytokines without antibodies.

Innate Immune System
- Non-specific, immediate response.
- Present in nearly all life forms.
Adaptive Immune System
- Specific to pathogens, has a lag time for maximal response.
- Found only in jawed vertebrates and induces immunological memory.

Skin acts as a primary barrier against infections.
Additional defenses include:
- Gastric acid and proteases in the stomach prevent ingested pathogens.
- Flushing actions of tears and urine expel pathogens.
- Mucus in respiratory and gastrointestinal tracts traps microorganisms.
- Enzymes like lysozyme serve antibacterial functions.

A relationship where one organism benefits without affecting the other.
Commensal flora can assist in nutrition, pathogen exclusion, and contribute to immune defense.
Lactobacillus in the vagina inhibits other bacteria by reducing pH.

Bone Marrow
- Source of all circulating blood cells and B cell maturation.
- Contains red marrow (hematopoietic tissue) and yellow marrow (fat cells).
Thymus
- Located behind the sternum, responsible for T cell differentiation and maturation.
- Contains thymic stromal and cortical cells which support T cell development.

Lymph Nodes
- Oval structures that filter lymph fluid, containing germinal centers for lymphocyte production.
- Enclosed by a fibrous capsule, with afferent and efferent lymphatic vessels.
Spleen
- Largest lymphatic organ, filters blood, and contains red pulp (blood components) and white pulp (lymphatic nodules).
- Plays a critical role in managing aged erythrocytes and immune responses.
MALT (Mucosa-Associated Lymphoid Tissue)
- Protects mucous membranes in areas such as the gut and respiratory tract.

Provides defense against harmful organisms and chemicals through two types of defense: nonspecific and specific (immunity).
Humoral immunity involves B cells which transform into plasma cells and produce antibodies.
Cell-mediated immunity entails T cells that directly destroy infected cells.