Lymphatic System Flashcards
Lymphatic System
- takes up fluid and moves it back to blood.
- large molecules and immunity.
Components of Lymphatic System
- Lymph fluid
- lymphatic vessels
- lymph nodes
lymph fluid
the interstitial fluid in lymphatic vessels.
-has a consistency similar to plasma.
lymphoid tissues and organs are separate from_______
lymphatic sys.
lymphatic vessels
are networks of drainage vessels that collect excess protein- containing interstitial fluid and return it to the bloodstream.
- are under really low pressure
- some fluid from capillaries go through interstitial to get to lymph vessels ( big things that couldn’t go through vessels)
lymphatic vessels have a ________
one way (one direction) flow toward the HEART.
lymphatic capillaries
- are widespread but absent from bones, nervous sys and teeth
- have no capillary beds; they weave between tissue cells and blood capillaries
- formed by squamous epithelium loosely overlapping endothelial cells
lymphatic capillaries are anchored by _______
collagen filaments so that any increase in interstitial fluid volume opens the minivalves rather than cause the lymph capillaries to collapse
lymphatic capillaries are very permeable due to_____
2 unique features:
- minivalves
- collagen filaments
fluid accumulates in capillaries to produce pressure
drives the lymph towards the the lymphatic system.
Mini-Valve Sys: Lymph. Capill.
regulates how much fluid gets in.
when fluid pressure is > press of lymph cap. the minivalves open to allow lymph in.
when pressure is > in lymph cap, the valves close
proteins can easily enter______
lymphatic capillaries
Lacteals
a specialized lymphatic capillary in the small intestine
- functions in amino acid digestion; transports absorbed fat from the small intestine to the bloodstream
- increase absorption in small intestine
In the small intestine lymph is _____ and called____
milky-white; chyle
lymph flow
- lymph capillary ~ 2. collecting lymphat. vessels~3.lymphatic trunks~4. lymphatic ducts
Lymphatic Vasculature
lymph cap merge into lymph collecting vessels that empty into lymphatic trunks then to lymphatic ducts
lymphatic collecting vessels have______
the three tunics;
- thinner walls than veins
- have more valves than veins because it is under low pressure
- anastomose more than veins
the FIVE major lymphatic trunks
- drain large body areas
1. bronchomediastinal-(2)
2. subclavian (2)
3. jugular (2)
4. lumbar (2)
5. intestinal-1
the lumbar trunk drains_____
the lower limbs
the intestinal trunk drains______
digestive organs
ALL of the trunks empty into the _______
lymphatic ducts in the thoracic region and which gets dumped back into the circulatory sys
the TWO ducts
Right and thoracic
the right duct drains________
the right side of the head, the right upper arm (upper limbs) and right side of thorax
the thoracic duct drains_______
the rest of the body and the lumbar & intestinal trunks
In some people the thoracic trunk starts as a sac called the_____
cisterna chyli
factors assisting in lymphatic flow
has “no pump”
- valves- one directional and prevent back flow
- muscular pump- contraction of skeletal muscle
- respiratory pump- used by veins; breathing causes pressure changes in thorax
- arterial pumping-arteries pulsations pushing through helps lymph push through
- smooth muscle contractions- helps push in vessels. ( found in tunics of lymphatic ducts and trunks except the smallest vessels.
antigens
anything that provokes an immune response (like bacteria and their toxins; viruses, mismatched RBCs or cancer cells
lymphoid cells
consists of immune sys. cells
- Lymphocytes
- macrophages
- dendritic cells
- reticular cells
lymphocytes
the main warriors of the immune sys.
has B and T cells.
B Cells (lymphocytes)
- have specific types for specific antigens
- attack free floating things which make it become activated.
- produce plasma cells that produce antibodies that are released and bind to pathogens (antigens) to mark it for destruction, don’t KILL.
- produce memory cells in case of being infected again
immunocompetent
- “mature”
- have to develop the ability to attack specific pathogens
- have to be activated in order to be able to attack which entails binding to pathogens to be activated
- cells have a receptor specific to something
T Cells
- activated T cells manage immune response
- activation usually kills what it activates on contact/site; attack damaged body cells
- activation cause memory cell production
- some directly attack and destroy infected cells
dendritic cells
phagocytic;
- engage in phagocytosis of foreign substances;
- capture antigens and bring them back to lymph nodes
reticular cells
create a matrix to hold other cells in place;
-a mesh (reticular fiber) called stroma- network of reticular cells that supports other cells in lymphatic tissue and organs
reticular cells
create a matrix to hold other cells in place;
- a mesh (reticular fiber) called stroma-
- stroma- network of reticular cells that supports other cells in lymphatic tissue and organs
receptors on cell surface either come from ____ or____ and are____
thymus; RBM; genetic
lymphoid tissue
- temporarily houses lymphocytes
- proliferation (multiply) site for lymphocytes
- dominates in all the lymphoid organs except the thymus
- composed of reticular connect. tiss.
- allows for detection of infection or damage
primary lymphoid organs
- thymus
- RBM
- where B & T cells mature
secondary lymphoid organs
where mature lymphocytes first encounter their antigens and are activated
- lymph nodes
- spleen
- tonsils
- peyer’s patch
- appendix
MALT
tonsils, peyer’s patch, appendix
lymph nodes
major organ
- found along lymphatic vessel area
- majority in neck, arm and groin
- only organ that cleans the lymph
spleen
largest lymphat. organ
- RBC graveyard (recycling)
- macrophages and lymphocytes
- filters blood
thymus
function early in life
- degenerates as we age
- is a derivative of the primitive pharynx lining then drops near heart.
tonsils
located at back of oral cavity and naval cavity and ear
peyer’s patches
distal part of small intestine
-inflammation causes appendicitis
Lymph node function
- surrounded by a capsule w/ trabeculae extensions
- multiple entries; one exit.
- lymph builds up
- lymph enters via afferent lymphatic vessels; lymph exits through efferent lymphatic vessels at hilus
- filters lymph through sinuses ( which are large lymphatic capillaries)
- fewer efferent vessels than afferent vessels, so the lymph slows allowing time for lymphocytes and macrophages to do work.
Spleen Action
“blood filter”
-blood delivered via splenic artery
-lymph filtered by lymphocytes ( immune functions) in WHITE pulp
then
-filtered by macrophages in red pulp ( worn-out RBCs and blood borne pathogens)
-cleansed fluid returns to splenic veins
* extracts aged and defective RBCs, platelets, and macrophages remove debris and foreign substances
thymus action
- no stroma in reticular cells
- action most prominent in newborns
- secretes thymosin and thymopoietin
- causes t-lymphocytes to become immunocompetent
- doesn’t directly fight antigens
- has no B cells
tonsils
gather and remove many of the pathogens entering pharynx in food or inhaled air.
-4 types: palatine, lingual, pharyngeal, tubal
palatine tonsils
- the most often infected tonsils
- back of oral cavity.
- paired
- the LARGEST tonsil
lingual tonsils
- sides/base of tongue
- paired
pharyngeal tonsils
- large
- known as the ADENOIDS
- located in posterior wall of nasopharynx
tubal tonsils-
- surrounds auditory canal tube into pharynx
- paired
tonsil histology
- have follicles with germinal centers surrounded by lymphoctyes
- crypts- pathways; trap bacteria and particulate matter; fluid trapped here; dead ends
tonsil action
- crypts– pathways; trap bacteria and particulate matter; fluid trapped here; dead ends
- bacteria pass through epithelium into the lymphoid tissue then
- the lymphoid tissue destroys the pathogens
- memory cells are formed
peyer’s patches
isolated clusters of lymphoid follicles
- destroy bacteria
- generate memory lymphocytes
lymphatic development
- developing veins bud off lymph sacs (“blood sacs”) at 5th week then
- jugular lymph sacs form first ( vena cava and iliac veins form)
- then these form a branching system of lymphatic vessels then
- connection of jugular lymph sac w/ jugular veins become right lymphatic duct and thoracic duct
- lymphoid organs develop from mesodermal mesenchyme that become reticular tissue EXCEPT the thymus.
the thymus develops______
FIRST
the thymus develops from______
endothermal derivative
Embryo thymus
- has no lymphocytes-mom does the work
- after birth the lymphoid organs populate w/ lymphocytes
