lymphatic system Flashcards
what does the lymphatic system do
returns extracellular fluid back to the cardiovascular system, provides immunity and aids in the digestion of fats
what helps fight against infectious agents
masses of lymphocytes found in lymph nodes
lymphatic capillaries
microscopic close ended tubes that extend into interstital spaces and recieve tissue through thin wall s
lymphatic vessels are formed by the merging of what
lymphatic capillaries
do lymph vessels have valves
yes
what do larger lymphatic vessels merge into
lymphatic nodes which merge into lymphatic trunks
lymphatic trunks do what
drain lymph from larger body regions
the two collecting ducts that trunks lead to
thoracic and right lymphatic duct
where do collecting ducts drain into
subclavian veins
where does tissue fluid originate
plasma
what is tissue fluid made of
water and dissolved substances that have passed through the blood capillary wall
tissue fluid generally lacks what
large proteins
what happens as the concentration of tissue fluid increases
colliod osmotic pressure increases
how does fluid become lymph
increasing hydrostatic pressure in interstitial spaces forces some tissue fluid into lymphatic capillaries
what does lymph formation prevent
edema
what is true about the flow of lymph and hydrostatic pressure (HP)
it s under low HP and may not flow readily without external aid
what moves lymph
contractions of skeletal muscle, smooth muscle in the walls of large lymphatic trunks, and the low pressure in the thorax created by breathing
conditions affecting the flow of lymph results in what
edema
lymphatic capillaries in the small intestine do what
absorb and transport lipids
lymph returns what into the bloodstream
small protein molecules and fluid
lymph transports what to the lymph nodes
foreign particles
MALT
mucosa-associated lymphoid tissue
what is MALT associated with
digestive, respiratory, urinary, and reproductive tracts
what are the lymphatic organs
lymph nodes, thymus, and spleen
typical shape of lymph nodes
bean shaped
lymph nodes are enclosed in what
CT that extends into the nodes
lymph nodes subdivide into what
nodules
what do lymph nodes do
filter potentially harmful foreign particles from the lymph before it is returned to the bloodstream
nodules contain what
masses of lymphocytes and macrophages and spaces through which lymph flows
where are lymph nodes located, and in what regions/cavities
in groups or chains along larger lymphatic vessels
cervical region
axillary region
supratrochlear region
inguinal region
pelvic cavity
thoracic cavity
abdominal cavity
what does the thymus do after puberty
slowly shrinks
what do lymph nodes contain
lymphocytes that act against foreign particles and macrophages that remove foreign particles
what is the thymus
a soft bilobed organ within the mediastinum
what do lobules contain
lymphocytes
what is the thymus composed of and subdivided into
composed of lymphatic tissue and subdivided into lobules
what leaves the thymus and provides immunity
T lymphocytes
what does the thymus secrete
thymosins
what do thymosins stimulate
maturation of T lymphocytes
where is the spleen
ULQ of abd cavity
what are the spaces in splenic lobules filled with
blood
what does the spleen resemble
a large lymph node encapsulated and subdivided into lobules by CT
what does the spleen do
filter foreign particles and damaged red blood cells from the blood
what does the spleen contain
macrophages and lymphocytes
types of immunity
innate and adaptive
what may cause an infection
the presence and reproduction of a pathogen
examples of mechanical barriers
hair, sweat, tears, saliva, urine
what are pathogens
bacteria, protozoa, fungi, and viruses
what is innate immunity
nonspecific immunity
mechanical barriers
inflammation
chemical barriers
natural killer (NK) cells
phagocytosis
fever
what are the mechanical barriers against infection
mucous membranes and the skin
damaged tissues release chemicals that attract what to the site
white blood cells
what is inflammation
tissues response to damage, injury, or infection
what may occur in fluids that accumulate
clotting
what may form around the damaged tissue to aid in preventing the spread of pathogens
a CT sac
what are some examples of chemical barriers
enzymes in gastric juices
tears
low pH in stomach
high salt concentration in sweat
interferons
defensins
collectins
activation of complement proteins in plasma
what do interferons do
stimulate uninfected cells to synthesize antiviral proteins that block the growth of viruses, stimulate phagocytosis, and enhance activity of cells that help resist infections and stifle tumor growth
what do defensins do (more like offensins)
make holes in bacterial walls and cell membranes
what do collectins do
protect against a wide variety of microbes by binding to them and facilitating phagocytosis (they go around collecting microbes and host a killing party for them)
what is the activation of complement proteins in plasma
it stimulates inflammation, attracts phagocytes, and enhances phagocytosis (sets up the party, invites the friends (phagocytes), and hypes up the friends)
why are NK cells so slay?
they secrete perforins which kill cancer cells and cells infected with viruses (its giving vigilante) AND proinflammatory stuff
what are the most active phagocytes in the blood
neutrophils and monocytes
monocytes? more like mothercytes!
she gives rise to what cell…?
macrophages which can be free or fixed in various tissues
what are phagocytic cells associated with
the linings of blood vessels in the liver, spleen, and mononuclear phagocytic system
what causes a fever
when a viral or bacterial infection stimulates lymphocyte cells to secrete IL-1 which temporarily raises body temperature
how does a fever help fight infection
elevated body temperature results in elevated iron in the blood which increases phagocytic activity towards the infection
how does the body know the difference between self and non self antigens
during fetal development the body cells take an inventory of their own proteins and other large molecules, and then lymphocytes develop receptors that allow them to tell the difference between self and non self antigens
what are haptens
small molecules that can combine with larger ones, becoming antigenic
where to lymphocytes originate
in red bone marrow
what happens to lymphocytes once they are released into the blood
some make to to the thymus where they are turned into T cells, others mature in the red bone marrow to become B cells
where to both T and B cells reside
lymphatic tissues and organs
when are T cells activated
when an antigen presenting cell displays a foreign anatigen
each variety of T and B cell respond only to what
a specific antigen
what does a macrophage acting as an accessory cell do?
it phagocytizes an antigen bearing agent, digests the agent, and displays the resulting antigens on its cell membrane in association with certain MHC proteins
what to T cells react to
cell to cell contact (cellular immune response)
what to T cells secrete
cytokines such as interleukens, that enhance cellular response to antigens and stimulate proliferation of a T cell to enlarge its clone
T cells also secrete substances that are toxic to their target cell
when does a helper T cell become active
when its specific antigens are displayed
what does a helper T cell do once its activated
stimulates a type of B cell to produce antibodies for the specific antigen
what does a cytotoxic T cell do
recognize foreign antigens on tumor cells who’s surfaces indicate that they’re infected with a virus
what do cytotoxic T cells secrete
perforin to destroy cells infected with a virus
what do memory T cells do
allow for immediate response ti second and subsequent exposure to the same antigen
when are B cells activated
when it encounters an antigen that fits or when stimulated by a helper T cell
what do some B cells differentiate into
anti-body producing plasma cells
what is the humoral immune response
when antibodies react against the antigen bearing agent that stimulated their production
where do memory B cells come from
further differentiated B cells
what are immunoglobulins
soluble proteins called antibodies
what constitutes the gamma globulin fraction of plasma
immunoglobulins
what does each immunoglobulin consist of
four linked chains of amino acids
antigen-binding sites
variable regions at the end of the 4 amino acid chains of immunoglobulins that react with antigens
the 5 major types immunoglobulins
IgG, IgA, IgM, IgD, and IgE
which immunoglobulins make up most of the circulating antibodies
IgG, IgA, and IgM
what do antibodies do?
directly attack antigens
bind antigens to activate their complement
stimulate local tissue changes that are unfavorable to antigen bearing agents
what does the direct attack of an antigen result in (3 things)
agglutination
precipitation
neutralization
what do activated complement proteins do
alter infected cells to be more susceptible to phagocytosis
attract phagocytes
lyse foreign cell membranes
during the primary immune response, antibodies are produced for how long
several weeks
what is the primary immune response
B and T cells encountering an antigen that they are specialized to react to
what is the secondary immune response
memory cells rapidly respond to subsequent exposure to an antigen
what immunity protects populations
herd immunity
example of naturally acquired active immunity
a person encounters a pathogen and has a primary immune response
example of artificially acquired active immunity
a person receives a vaccine containing a dead or weakened pathogen
example of artificially acquired passive immunity
a person receives a vaccine with an antiserum or antitoxin
example of naturally acquired passive immunity
antibodies pass from mother to baby in utero
which lasts longer, active or passive immunity
active lasts much longer than passive
what is a hypersensitivity reaction
excessive misdirected immune response that may damage tissue
what is a type 1 hypersensitivity (immediate reaction)
a person is born with the ability to overproduce IgE in response to an allergen
what do allergic reactions actually result from
mast cells bursting and releasing allergy mediators like histamine
type 2 hypersensitivity (antibody-dependent cytotoxic hypersensitivity)
when a blood transfusion is mismatched
type 3 hypersensitivity (immune complex hypersensitivity)
involve autoimmunity and immune reactions against self antigens
type 4 hypersensitivity (delayed-reaction hypersensitivity)
can occur in anyone and inflame the skin, results from repeated exposure to chemicals or cosmetic products
what are MHC antigens
substance that helps the body accept foreign tissue from a transplant
autoantibodies (👎)
the little jerks responsible for autoimmune diseases :((( they attack the bodies own tissues
