Lymphatic System Flashcards
functions of lymphatic system
1) differetiation of lymphocytes- T cells, B cells, and NK cells (primary lymphoid structures)
2) consist of lymphocytes and more Bcells to battle infectious agents (secondary lymphoid structures)
3) maintains normal blood volume
4) maintains chemical composition of the interstitial fluid
5) provides and alternative route for the transport of hormones, lipids, and nutrients/waste products
primary lymphoid
where stem cells divide and become immunocompetent, includes the thymus and red bone marrow
secondary lymphoid
where immune responses occur; includes lymphatic nodules, lymph nodes, spleen
lymph consists of
interstitial fluid, lymphocytes (T and B), and macrophages
lymphatic system consists of
lymph, lymphatic vessels, lymphoid tissues, lymphoid organs, red bone marrow
flow of lymph
blood capillaries, interstitial space, lymphatic capillaries, lymphatic vessels, lymph nodes, lymphatic trunks, lymphatic ducts, junction of internal jugular and subclavian veins
lymphatic ducts empty lymph into
the junction of jugular and subclavian veins of the cardiovascular system
lymphatic vessels pass lymph to
lymphatic ducts
valves ensure
one way flow of lymph
efferent lymphatic vessels carry lymph from
lymph nodes
lymph nodes do what?
remove foreign substances through filtering, phagocytosis, and immune reactions
afferent lymphatic vessels carry lymph from
lymphatic capillaries to lymph nodes
lymphatic capillaries do what?
absorb interstitial fluid and pass lymph to afferent lymphatic vessels
blood plasma
filtered from blood capillaries into interstitial spaces to become interstitial fluid
lymphatic capillary structure
larger in diameter and greater permeability compared to blood capillaries, ends of the endothelial cells that make up the wall of the capillary overlap, only allows fluid to enter
anchoring filaments
attach to endothelial cells to surround tissues
superficial lymphatics
found in subcutaneous layer, the mucous lining of the digestive, respiratory, urinary, and reproductive tracts, and the serous lining of the pleural, pericardial, and peritoneal cavities
deep lymphatics
collect lymph from skeletal muscles and tissues of the neck, limbs, and trunk; located by deep arteries and veins
superficial and deep lymphatic vessels converge to form
lymphatic trunks
what are the five major lymphatic trunks?
1) lumbar (R/L)
2) intestinal
3) bronchomediastinal (R/L)
4) subclavian (R/L)
5) jugular (R/L)
lymphatic trunks drain intro
lymphatic ducts
lymphatic ducts drain into
subclavian veins
thoracic duct collects lymph from
tissues inferior to the diaphragm and from the left side of the upper body (all five left major lymphatic trunks+right lumbar)
right lymphatic duct drains
right half of the body superior to the diaphragm
right jugular, subclavian, and bronchomediastinal trunks
cisterna chyli
a dilation of the thoracic duct, anterior to L2, receives lymph from the right and left lumbar trunks and intestinal trunk
lymphocytes
primary cells of the lymphoid system, respond to invading bacteria and viruses, abnormal body cells such as cancer cells, and foreign proteins such as toxins released by some bacteria
types: T cells, B cells, NK cells
where do T cells originate?
bone marrow, travel to the thymus gland and become activated by thymosin
different types of T cells
cytotoxic, helper, suppressor, memory
cytotoxic T cells
attack foreign cells and viruses
helper T cells
coordinates the immune response
suppressor T cells
coordinate the immune response
memory T cells
become activated if the same antigen appears in the body at a later date
B cells
originate and become immunocompetent in the bone marrow
different types of B cells
Plasma cells, Memory B cells
Plasma cells
produce antibodies (immunoglobulins) that react with antigens
Memory B cells
become activated if the same antigen appears at a later date
NK cells (natural killer)
attack foreign cells, attack normal cells that are infected with viruses, attack cancer cells, NK cells often called immunological surveillance cells
cell-mediated immunity
direct cell-to-cell attack
antibody-mediated immunity
humoral immunity because blood is main transport for the antibodies
thymus
posterior to the manubrium, reaches its greatest size by puberty, 2 thymic lobes and numerous lobules separated by septa, consists of a cortex and a medulla, primary lymphoid organ
cortex of the thymus
stem cells that differentiate to form T cells, mature T cells migrate to the medulla
medulla of the thymus
T cells that remain inactive until they enter circulation and thymic corpuscles
thymic corpuscles
unknown function, may be the site of T cell death
Lymphoid nodules
secondary lymphoid tissue, have a germinal center, found in Mucosa-associated lymphoid tissue (MALT) -GI, urinary, reproductive tracts and respiratory airways, aggregated lymphoid nodules (Peyer’s patches and appendix), tonsils
germinal center of nodule
contains lymphocytes, appears white and contains B cells, dendritic cells and macrophages
crypt
an invagination of the epithelium which increases the surface area, epithelium is thin here to allow transfer of antigens from environment to the lymphoid cells of the tonsils
tonsils
5 sets: one pharyngeal(adenoid), two palatine, two lingual
Waldeyer’s ring
a tonsillar ring at the junction of the oral cavity and the oropharynx and at the junction of the nasal cavity and nasopharynx
lymph nodes
secondary lymphoid organs that are scattered throughout the body (often found in groups) , covered by a capsule of CT that divides the node into compartments
stroma of a lymph node
reticular fibers and fibroblasts
cortex of a lymph node
contains mostly secondary nodules which form in response to an antigen, where plasma and memory B cells are formed
paracortex/inner cortex of lymph node
doesn’t have lymphatic nodules, where dendritic cells present antigens to T cells causing T cells to proliferate
medulla of lymph node
contains B cells, plasma cells producing antibodies that have migrated out of the cortex and macrophages
how does lymph enter a node?
afferent vessels that have valves
where does the lymph travel after entering the node?
through a series of sinuses
sinuses
irregular channels that contain branching reticular fibers, lymphocytes and macrophages
after the sinuses, where does lymph travel?
the efferent vessels in the hilum (efferent also have valves)
how does a lymph node filter the lymph in the sinuses?
foreign substances are trapped by the reticular fibers, macrophages destroy some foreign substances, and lymphocytes destroy other foreign substances by immune responses
most concentrated areas of lymph nodes
cervical, axillary, breasts, abdominal, inguinal regions
why are there certain regions that are more concentrated with nodes?
because here the body is more susceptible to injury or invasion
spleen
largest lymphoid organ, secondary
diaphragmatic surface
smooth, convex and conforms to the diaphragm
visceral surface the hilum and indentations of the spleen
gastric, renal, colic impressions
spleen consists of
capsule, red and white pulp
red pulp
contains large quantities of blood
1) removal of ruptures, worn out or defective RBCs and platelets by macrophages
2) storage of 1/3 of platelets
3) production of RBCs in fetus
white pulp
forms lymphoid nodules
B cells, T cells and macrophages carry out immune reactions similar to lymph nodes
