lymphatic system Flashcards
(12 cards)
state 3 functions of the lymphatic system
- collect excess fluid and return it to the blood stream
- filter out cellular material (pathogens and cancer cells), activating the immune system
- absorb fats in the small intestine
what is lymph
a clear yellow liquid that carries white blood cells (especially lymphocytes)
function of a lymph capillary
collects intercellular fluid from tissue
it has a blind end (not continuous like vascular system)
they are slightly more permeable and larger than blood capillaries allowing disease causing organisms to easily pass through them
function of lymph vessels
originate from lymph capillaries. they are thin and vein like with valves that open and close as muscles contract preventing backflow.
function of lymph nodes
they are bean shaped nodes surrounded by connective tissue spread across the vessels in intervals. they contain lymphocytes, macrophages and plasma cells.
how does lymph return to the bloodstream
- lymph passes through the lymph capillaries and travels through lymph vessels
- It will travel through several nodes before returning to the circulatory system via two lymphatic ducts at the subclavian vein (near collarbones)
what do lymphocytes do
apart of the immune response. when infection occurs they are formed faster causing nearby lymph nodes to become swollen/sore.
e.g. cut on finger= swollen arm pit
what do macrophages do
destroy disease causing particles through phagocytosis
engulf/ingest the particle, killing it within 10-30 minute
projections from the phagocytic white blood cell surround the forgien particle
role of lymphatic system in defence against disease
lymph enters the capillaries and travels to nodes via vessels. the disease causing particles that weren’t trapped through the external defence system (nose hair) will become trapped in the criss-cross tissue fibre of the lymph node.
macrophages will ingest the particles via phagocytosis and if infection occurs, extra lymphocytes will form.
where does lymph come from
blood enters blood capillaries at a high pressure via arteries. The high pressure forces some of the fluid (plasma) through the semi permeable membrane into the intercellular fluid.
state the order lymph travels (basic)
into lymph capillaries- lymph vessels- lymph nodes- lymph vessels- lymph ducts- subclavian vein
what are lacteals
apart of the villi in the small intestine, the absorb fatty acid and glycerol molecules
fats move through the lymphatic system before entering the blood stream
