16, 17. The Immune System Flashcards
What is the timeline of the innate and adaptive immune systems?
🔸 0-4 hours, Fixed defences of the innate (non specific) immune system
🔸 4-96 hours, Induced defences of the innate immune system
🔸 96 hours, adaptive (specific) response
What is the general process of the removal of an infectious agent?
🔸Infection recognised by phagocytes and soluble components (eg. Lysosomes) of the innate immune system
🔸Recruitment of effect cells (e.g macrophages) of the innate response
🔸 transport of antigen to lymphoid organs, for recognition by T and B cells, and proliferation of these cells
What is a pathogen?
Harmful organisms and viruses
What is immunity?
The ability to avoid disease when invaded by a pathogen
How specific is innate immunity?
🔸 Non specific
🔸 Involves recognising components that are common to many pathogens
🔸 Typically very rapid response
What is the specificity of adaptive immunity?
🔸 Able to distinguish between healthy cells (self) and abnormal cels and molecules that are not self
🔸 Involves recognising components that are specific to each particular pathogen
Where do our immune system cells come from?
BLood cell production
🔸 Multipotent hematopoietic cells in the bone marrow give rise to lymphoid progenitor cells that become B or T lymphocytes
What immune system cells are associated with the innate response?
Macrophage, mast cells, complement proteins
What immune system cells are associated with the adaptive immune responses?
B cells, T cells, antibodies, Th cell, Tc cell
What immune cells are associated with both?
T cells and Natural killer cells
Where do B cells mature?
B cells mature in the bone marrow, then circulate in blood and lymph
Where to T cells mature
Immature T cells migrate from bone marrow to thymus to mature, then circulate in blood and lymph
What is plasma?
🔸Fluid remaining when white blood cells, red blood cells, platelets are removed
🔸Considered the connective tissue of blood
What is the difference between plasma and lymph?
Plasma and lymph have a similar composition but plasma contains both white and red blood cells while lymph contains no red blood cells
What are lymph nodes?
Small round structures at many sites along the lymph vessels and contain white blood cells/leukocytes
As lymph passes through the nodes, it is filtered and inspected for non self molecules/pathogens
How are immune system cells transported?
In the blood and lymphatic system
What are macrophages and what is their function?
They engulf and digest pathogens, cellular debris and pathogen infected cells.
Can move through leaky blood vessels to site of damage
What are mast cells?
Found surrounding blood vessels and nerves in the connective tissue of most organs, and in the boundaries between the internal and external environment
What do macrophages secrete?
Defensins
Nitric oxide
What do mast cells secrete?
Histamine
Prostaglandins
Tutor necrosis factor
What roles do complement proteins carry out?
- Chemotaxis (attracting phagocytes to an injured area
- Attach to antigens on pathogen surface or to an antibody bound to a pathogen, helping phagocytes to recognise and kill pathogens
What does the first line of defence involve?
Skin, mucus, cilia, chemicals (lysosome), flora