The Immune System Flashcards
What is the immune system?
The ability to resist damage from pathogens, toxins and internal threats
What are the two types of the immune response?
Nonspecific innate immunity
Specific acquired immunity
What is the immunogens functions?
The trigger of the body’s immune system
What does the nonspecific innate immunity mean?
The body will respond no matter what is the cause
What does specific acquires immunity mean?
Improves each time it meets an invading pathogen
What is the lymphatic system?
System of vessels, cells and grand that carries excess fluids to the bloodstream and filters pathogens form the blood
What is lymph?
Lymph is the interstitial fluid once it has entered the lymphatic system
What are the function of the lymphatic system?
Fluid balance
Lipid absorption
Defence against pathogens
Where does the lymphatic system lead to?
The neck where the fluid is drained to the bloodstream through ducts
In what direction does the fluid move in the bloodstream?
One direction through the valves (not circulating)
What are the lymphatic capillaries in the small intestine called?
Lacteals
What are the stages of organisation for the drainage into the neck?
Lymphatic capillaries form vessels which form trunks which form 2 ducts
Where does the right duct drain?
Into the top right side of the body
Where does the left duct drain to?
Everywhere in the body except for the top right side of the body
Why is one of the lymphatic organs the tonsils?
Because this is where the protective ring of lymphatic tissue is around the nasal and oral cavities as these receive many pathogens
Where are the lymph nodes?
Along the lymph vessels
What is activated when lymph flows through nodes?
The lymphocytes are activated to divide and remove pathogens using macrophages
What does the lymphatic organ, the spleen do?
Filters blood
What happens in the white pulp in the spleen?
Lymphatic tissue surrounded the arteries and can stimulate to divide
What happens in the red pulp in the spleen?
Where the macrophages and rbc’s remove foreign substances and worn out rbc’s through phagocytosis
When does the lymphatic organ, the thymus begin to degrade?
Around 20 years old
What pushes the fluid to the neck?
Muscle contraction
What are the key cells of the immune system?
Leukocytes
What are the six types of leukocytes?
Eosinophils
Basophils
Neutrophils
Monocytes
Lymphocytes
Dendritic cells
What are the physical barriers of the immune system?
Skin
Mouth
Stomach
Mucosal epithelia
Fluid that are washed from the body
What do chemical mediators produce?
The immune response
What happens when complement chemical mediators are activated?
A series of reactions happen where each complement protein activated the next
What do complement chemical mediators act as and why?
Act as chemotactic agents to attract phagocytise cells to the site of inflammation
What are the three types of chemical mediators aiming to activate?
C3
What are cytokines chemical mediators?
Small signalling molecules released from cells to trigger immune response
What are interferons chemical mediators used for?
To induce cells to produce viral nucleic acids and proteins from viruses and activate other immune cells
What are the smaller chemical mediators?
Histamine
Prostaglandins
Leukotrienes
What do the smaller chemical mediators cause?
Vasodilation
Increase vascular permeability
Stimulate phagocytosis
What are the stages of phagocytosis cells?
Neutrophils act first then die
Macrophages act in the later stages of infection
What are the inflammatory cells?
Basophils
Mast cells
Eosinophils
These are all wait for a response then degrade to release histamine in a tissue injury
The inflammatory response leads to …
Vasodilation (increase blood flow)
Vascular permeability (leakage of fluids into tissue which leads to swelling, more phagocytes and clotting factors)
Recruitment of phagocytes in tissue (increases temperature to increase the activity of phagocytes)
What is adaptive immune response?
Specific and has memory
Responsible for antigens (substances that bind to receptors on lymphocytes)
What are the two ways adaptive immunity is mediated?
Cell mediated (T cells)
Antibody mediated (protein generated by plasma cells)
What does adaptive immunity require?
Antigen recognition and Mhc molecules
What are the two types of cells that lymphocyte proliferation uses?
Helper T cells
B cells
What are B cells?
Phagocytosis same antigen as helper T cell to stimulate B cells
What do antibodies bind to?
Antigens and destroyed to make extracellular antigens
What are the shape of proteins in antibody immunity?
Y shaped molecules
Consisting of four polypeptide chains (two heavy, two light)
Have a variable top where the antigen binds
Also they are immunoglobulins
What is primary response to antibody production?
When B cells undergoes several divisions after an exposure to antigen, that forms plasma cells and memory B cells that produce antibodies that produces disease symptoms
What is the secondary response to antigen production?
Previously exposed to antigen where memory B cells divide quickly to form plasma cells and quickly produce antibodies and makes memory cells and is quicker to produce antibodies
What are the different effect of antibodies?
Inactive antigen
Activated complement cascade
Initiates release of inflammatory mediators
Facilitate phagocytosis
Antibody dependant cellular activity
What are the antibodies produced in allergic response?
IgE and IgG
What do IgE antibodies do?
Immediately bind to mast cells and basophils
IgG
Most abundant antibody
Found in blood, lymph and intestines
Protects against virus and bacteria
IgA
Found mainly in sweat, tears saliva, mucus, milk and GI secretions
Provides localised protection on mucous membranes against bacteria and viruses
IgM
First antibody in class to be secreted by plasma cells after initial exposure to an antigen
Found in blood, lymph and as antigen receptors on surface of b cells
IgD
Found in blood, lymph and as antigen receptors on surface of B cells
Involved in activation of B cells
IgE
Found on mast cells and basophils
Involves in allergic and hypersensitivity reactions and provides protection against parasitic worms
What are antibodies produced from?
Plasma cells
What are the WBC’s b lymphocytes and t lymphocytes known as?
Memory cells
Keeps a record of every microbe it has ever defected
What are the three types of immunity?
Innate
Acquired
Passive
What is the function of macrophage?
They are found in tissues and secrete cytokines in response to infection
where do b cells mature?
bone marrow
where do t cells mature?
thymus
