lymphatic system Flashcards
lymphatic system
return excess tissue fluid and leaked plasma proteins to blood vascular system via lymphatic vessels, removes cellular debris & infection
immune system
protects body from foreign organisms, confers immunity to disease
main components of immune system
lymphocytes, lymphoid tissue, lymphoid organs
what is the function of lymphatic vessels?
collect excess tissue fluid and blood proteins and return them to bloodstream
how does the fluid flow?
only towards the heart, a one-way path
what is the tissue fluid called when it is within lymphatic vessels?
lymph
lymphatic capillaries
smallest lymph vessels, first to receive lymph, found where blood capillaries are, permeable causing them to collect tissue fluid and bacteria/viruses
lymphatic collecting vessels
collect from lymph capillaries, accompany blood vessels (superficial travel with superficial veins, deep ones in thorax & abdomen with deep arteries)
lymph nodes
found along lymphatic collecting vessels, lymph is filtered on its way to venous system
lymphatic trunks
collect lymph from collecting vessels
lymphatic ducts
empty into great veins of neck
highly permeable vessels near blood capillaries…
increase volume of tissue fluid, minivalve flaps open & allow fluid to enter
high permeability allows the entrance of…
tissue fluid & protein molecules, bacteria, viruses & cancer cells
lacteals
specialized lymphatic capillaries that receive digested fats, fatty lymph (chyle)
where are lacteals located?
in villi of small intestine
chyle
fatty lymph
lymph is propelled by…
skeletal muscles bulging, nearby arteries pulsing, tunica media of lymph vessels
how many lymph nodes does the human body contain?
500
location of superficial lymph nodes
cervical, axillary, inguinal regions
location of deep nodes
tracheobronchial, aortic, iliac
5 lymphatic trunks
lumbar, intestinal, bronchomediastinal, subclavian, jugular
lumbar trunks
receive lymph from lower limbs and pelvic organs
intestinal trunk
receives chyle from digestive organs
bronchomediastinal trunks
collect lymph from thoracic viscera
subclavian trunks
receive lymph from upper limbs and thoracic wall
jugular trunks
drain lymph from head and neck
3 lymphatic ducts
cisterna chyli, thoracic duct, right lymphatic duct
cisterna chyli
located at union of lumbar and intestinal trunks
thoracic duct
ascends along vertebral bodies, empties into venous circulation draining 3/4 of the body, junction of left internal jugular & subclavian veins
right lymphatic duct
empties into right internal jugular and subclavian veins
two main classes of lymphocytes, where do they originate
B and T lymphocytes, bone marrow
what travels to thymus gland?
T lymphocytes
what stays in the bone marrow?
B lymphocytes
what type of tissue is the most important of the immune system?
lymphoid tissue, large numbers of lymphocytes gather to fight infection
thymus (primary, bone marrow)
where immature lymphocytes develop into T lymphocytes, most active in childhood
secondary lymphoid organs
function to gather and destroy infectious microorganisms and store lymphocytes
spleen
removal of bloodborn antigens, destruction and removal of old or defective blood cells
tonsils
arranged in a ring at entrance of pharynx to gather & remove pathogens, 4 groups (pharyngeal, lingual, palatine, tubal)
what are the four groups of the tonsils
palatine, lingual, pharyngeal, tubal
