Lymphatic system Flashcards
function of the lymphatic system?
Tissue drainage
Return of plasma and plasma proteins
Absorbed fat transport from gut
Immunity
Lymph composition?
lymph is fluid and plasma protein only.
What is added to lymph as it flows through lymphatic capillaries and channels?
lymphocytes
What is added to lymph in the small intestine?
fats
How does lymph flow through vessels
relies upon muscle contraction, pressure changes and gravity.
Uni-directional because of valves that prevent back flow
what happens to fluid flow during infection?
Fluid flow by osmosis into extracellular spaces increases (swelling) due to protein accumulation in ECF (ie antigens). This drives increased lymph flow and therefore immune response in nodes
What are lymph nodes?
main lymphoid organ
acts as a checkpoint- closely regulates and inspects lymph fluid by immune cells (lymphocytes) within lymph nodes
trigger immune response if foreign pathogen traces are identified
- can be isolated or grouped
Where is the first place the immune system sees an anitgen?
in the lymph node
on return of lymph to where it needs to be it transverses lymph node
Lymph node- histology
kidney or oval shaped
lymphoid follicles:- primary and secondary
secondary have germinal centre with more WBC’s within these
Checkpoints in the body other than lymph nodes
MALTs
Preyer’s patches
MALTs
mucosa-associated lymphoid tissues
can be found in mucus membranes around the body outside of lymphatic vessels
example: tonsils which try to remoce pathogens before they enter the GI tract or lungs
Preyer’s patches
checkpoint along the GI tract
in the distal portion of small intestine (bottom)
small mass of lymphatic tissue (aggregated lymph nodes) that monitor intestinal bacteria
What would happen if the lymphatic system didn’t work effectively?
if fluid wasn’t returned to circulatory system (ie back to the blood)
then there would be a serious drop in BP and little to no O2 delivery or waste removal
What is so bad about a tumour or blockage located in the lymphatic vessels?
tumour or blockage would be dangerous as it could lead to edema (abnormal accumulation of fluid in certain tissues) or swelling (which restrains blood flow)
Where does the Right lymphatic duct drain to?
Drains all the lymph collected from the upper right area of the torso as well as the right arm and right side of the head and thorax and it feeds them into the internal jugular vein
drainage by thoracic duct?
takes lymph from the rest of the body (everywhere not drained by right L.D) and feeds it into the subclavian vein
Inflamed nodes?
if a node is overwhelmed by antigen that it’s trying to fight then it becomes enlarged and this can be an early sign of disease or infection
Where are lymphocytes found?
in the loose reticular connective tissue that makes up a large part of the nodes and most of your other lymphoid organs
Primary tumour (lymphoma) example
Hodgkins- rare cancer of the lymphatic system
Secondary tumours
result of metastasis from other sites
Examples of infections of the lymph nodes
tb
glandular fever
what is the rule regarding deep lymphatic drainage route?
it follows routes of arterial supply
Route of fat molecules through body
doesn’t go straight to the liver, instead, lymph returning from the small intestine is laden with absorbed fats which also drain to the superior vena cava and eventually to the liver for absorption
Primary lymphoid tissue
thymus
where hematopoeitic stem cells are produced by bone marrow and differentiate into T-cells.
Secondary lymphoid tissue
Secondary lymphoid tissues are sites where lymphocytes interact with each other and non-lymphoid cells to generate immune responses to antigens
e.g spleen, lymph nodes, peyer’s patches
Spleen
largest lymphatic organ in the body
- upper left quadrant of abdomen (peritonised, peritoneum membrane)
contains a large amount of blood, routinely discharged via smooth muscle action
Spleen histology
section of spleen has red pulp on outside, white pulp inside.
White pulp is where T and B cells are found.
role of spleen
filter blood but also involved in immune response
Where is there no lymph drainage from?
epithelium, cartilage, bone or CNS or from the majority of the spleen and liver
Superficial inguinal nodes drain which part of the body?
everywhere from below the belly button except the gonads (an organ that produces gametes; a testis or ovary) and lateral foot
