Lymphatics + immunity Flashcards
lymphatic system role
protect against disease
3 things lymphocytes respond to
environmental pathogens
toxins
abnormal body cells eg. cancer cells
structure of lymphatic vessels
- endothelial cells loosely bound together w/ overlap
-> acts as one way valve for entry of interstitial fluid
where does lymph from the right upper limb + right side of head + neck enter
right lymphatic duct -> into right subclavian vein
where does lymph from the rest of the body enter
thoracic duct -> empties into left subclavian vein
what is lymphedema
- blockage of lymph drainage
- interstitial fluid + causes severe swelling
- fluid becomes stagnant + causes accumulation of toxins + pathogens
where are lymphocytes produced
lymphoid tissues
lymphoid organs
red bone marrow
-> travel to site of infection as part of immune response
where are T and B cells produced
T = thymus
B = bone marrow
function of cytotoxic T cells
attack virally infected cells
specific cell mediated immunity
function of memory T cells
formed in response to foreign substances
remain in body to give ‘immunity’
function of T helper cells
stimulate function of T and B cells
function of suppressor T cells
inhibit function of T + B cells
function of B cells + effects
- differentiate into plasma cells
- plasma cells produce + secrete antibodies
-> binding of a specific antibody to a specific target antigen initiates specific antibody mediated immunity
NK cells function
- responsible for immunological surveillance
- attack foreign cells, virus infected cells + cancer cells
- non-specific immunity
Distinguish b/t lymphoid tissues + lymphoid nodules
lymphoid tissues = connective tissue dominated by lymphocytes
lymphoid nodules = small, localised collection of lymphoid tissue
-> eg. respiratory tract (tonsils)
function of the thymus
- produce hormones that develop + maintain normal immune system function
-> thymosin = protein produced in thymus that promotes production of lymphocytes
3 functions of the spleen
- removal of abnormal blood cells + other blood components by phagocytosis
- storage of iron recycled from RBCs
- initiation of immune responses by B + T cells in response to antigens in circulating blood
list the 7 categories of innate immunity
- physical barriers
- phagocytes
- immunological surveillance
- interferons
- complement
- inflammatory response
- fever
2 examples of physical barriers
integumentary system
epithelia lining
2 examples of microphages and how they work
- neutrophils + eosinophils
-> leave the bloodstream + enter peripheral tissues to fight infections
how do activated macrophages respond to pathogens
- engulf pathogens + destroy it with lysosomal enzymes
- bind to pathogen so other cells can destroy it
- destroy pathogen by releasing toxic chemicals into interstitial fluid
difference b/t fixed + free macrophages
fixed = stay in specific tissues or organs eg. dermis + bone marrow
free = travel throughout whole body
how do NK cells perform immunological surveillance
recognise + destroy abnormal cells by:
- identifying + attaching to abnormal cell eg. cancer cell or virally infected cell
- golgi apparatus in NK cell forming perforin vesicles
- vesicles release proteins called perforins
- perforins lyse abnormal plasma membrane
steps to interferon defence
- cytokines released b y activated lymphocytes + macrophages
- infection of a cell by a virus stimulates expression of interferon proteins
- interferon proteins are exocytosed + bind to receptors on an uninfected cell -> triggers production of antiviral proteins
- antiviral proteins block replication of the virus -> causes death