Immunology Flashcards
What is the immune system?
A protection system from internal and external threats.
What happens if IS is over active?
Allergies and autoimmune diseases.
What happens if IS is under active?
Infection and cancer.
What is innate immunity?
Rapid response. Complement proteins bind to pathogens. Macrophages engulf and digest pathogens. Kupffer cells in liver engulf 2 million RBC every second. Dynamic process.
What is acquired/adaptive immunity?
Slow response. Cytotoxic T cells kill pathogens by poisonous proteins that puncture the surface of the membrane. Macrophages then clear them away. Acquired and innate work together.
What is in the immune system?
Cells and organs and soluble components of body tissue and fluid that protects the body against pathogens and endogenous molecules. Surveillance to maintain tolerance to self and surveillance to protect and defend against malignancy.
What is the first line of defence?
Innate immunity. Physical barriers - skin, mucous barriers, lower pH in the vagina and nasal passages etc.
What is the second line of defence?
Innate immunity. Phagocytes, NK cells, mast cells, complement proteins, interferons, inflammation and fever.
What is the third line of defence?
Acquired immunity. Lymphocytes - T and B cells and dendritic cells.
What does skin do?
Continual shedding of the epidermal layer gets rid of pathogens, the epidermis is waterproof, has lower pH, sebaceous glands that release sebum which has antimicrobial properties and defensins that disrupt bacterial membranes. Also, commensal bacteria that compete with pathogens on the skin.
What are lymphoid organs?
Primary = bone marrow and thymus. Secondary = spleen, bronchitis lymph nodes etc.
Where does innate immunity work?
Peripheral tissue. Detection of infectious agent, containment/elimination of agent using non specific mechanisms then pass on info about nature of infection to acquired immune system.
How does innate immune system work?
PAMPS and PRR and TLR at the surface of all innate immune cells. Germline encoded receptors.
Describe PAMPS and PRR
Every pathogen expresses foreign pathogen-associated molecular patterns that are recognised by pattern recognition receptors.
Describe TLR
Toll-like receptors e.g. TLR-5 bins to flagellin part of flagella which binds to the ligand and changes the shape of intracytoplasmic portion, binds to a protein that initiates signalling pathway in the macrophage that activates it.
