L27 - intro to the immune system Flashcards
what is the immune system?
- prevents/ limits infection
- complex network of cells, organs, proteins, tissues that defend body from pathogens
- recognise pathogens
- recognises abnormal cells (cancer cells)
components of immune system
- organs and cells
- lymph system
- circulatory system
2 types of immunity
- innate: non specific
- acquired/adaptive: specific
what is innate immunity?
- aka natural immunity
- non-specific defence mechanism
- initial response to remove microbes and prevent infection
- fast response (mins to hrs)
functions of innate immunity
components of innate/ natural immunity
- physical barriers: mucous lining in nose
- chemical barriers: stomach acid
- protective cells: NK cells, WBC that destroy invaders
- sneezing, coughing, vomiting
examples of physical and chemical barriers
- skin, hair, cilia
- mucous membrane
- tears
- mucus and chemical secretions
- digestive enzymes in mouth
- stomach acid
- blood brain barrier
how are macrophages, neutrophils and mast cells involved in innate immunity?
remove pathogens by phagocytosis
how are natural killer (NK) cells involved in innate immunity?
eliminate infected or abnormal host cells
how are dendritic cells involved in innate immunity?
- direct microbial activity
- secrete chemicals that can recruit and activate other immune cells
what causes inflammation?
- physical barrier is breached
- infection
what inflammation do?
- eliminates pathogens and promotes tissue repair
- releases signalling molecules (cytokines & chemokines)
- recruits immune cells to site of infection
- causes heat, pain, redness, swelling
what is the complement system?
- 30 diff plasma proteins
- made in liver
- but circulates in the blood
- helps destroy pathogens
- immune cell activation
- clearance of immune complexes
- activated through different pathways
- bridge between innate + adaptive immunity
what is adaptive/aquired immunity?
- specific
- target defence mechanism
- initiated when innate response fails to clear pathogen
- detects antigens on pathogen
- adapts to recognise and remember specific pathogens
- long lasting protection
- slow response
2 types of adaptive immunity
- cellular
- humoral
function of the adaptive immune system
dendritic cells and cell mediated immunity
dendritic cells present antigen to T cells to trigger a response of antigen (diff types of T cells)
what is a cytotoxic T cell in cell mediated immunity?
they directly attack and kill infected/ abnormal cells
helper T cells in cell mediated immunity
assist B cells in antibody production and activate other immune cells
regulatory T cells in cell mediated immunity
help maintain immune balance and prevent excessive responses
