4. Lymphatic System Flashcards
3 anatomic components of lymphatic system
- lymph fluid
- lymphatic vessels
- oganized lymphatic tissues/organs
- spleen, liver, thymus, tonsils, appendix, visceral lymphoid tissue, lymph nodes
physiologic function of lymphatic system
immune
digestive
fluid balance
waste
When does lymphatic development begin?
5th week of gestation
(significant presence by 20 weeks)
What aspects of lymphatic system come from mesoderm?
lymphatic vessels
lymph nodes
spleen
myeloid tissue
What aspects of lymphatic system come from endoderm?
thymus and parts of tonsils
When do lymphoid tissues start to regress?
15-16 y/o
How many L of fluid move from capillaries to interstitial space each day?
30 L of fluid
(90% to capillaries, 10% to lymphatic system)
(1/2 diffused plasma proteins re-enter system via lymph)
When fluid overload occurs, lymphatic systems helpes prevent damage by clearing the excess.
“second/third spacing”
purification and cleansing via lymph fluid
bathes organs
cleanses extracellular spaces of particulate matter, toxins, bacteria, cell waste products, and post-injury biochemical by-products
fluid travels from vessel to node
defense via lymph fluid
brings toxins, bacteria, and viruses into contact w/ organized lymph tissue
contain high concentration of immune cells and APCs
maturation of immune cells = immunity
What is the role of OMT in treating lymphatics?
free flow of lymph necessary for appropriate immune function
OMT used to establish better free flow of lymph
fat absorption occurs via ___
chylomicrons (packaged form of fats)
How do chylomicrons get to the venous system?
travel via lacteals > larger lymph vessels > thoracic duct > venous system
substances that leak out of arterial capillries into interstitium
eventually taken up by lymphatic capillaries
lymph fluid
components of lymph fluid
fluids, proteins, electrolytes, and cells
immune cells
foreign Ag
bacteria and viruses
clotting factors
chylomicrons (post-prandial)
Which tissues do not have lymphatic vessels?
epidermis
endomysium of muscle
cartilage
bone marrow
Trace the route of lymph through lymphatic vessels.
terminal lymphatics > collecting vessels > afferent lymph vessels > lymph node(s) > efferent lymph vessels > lymphatic trunks > thoracic duct or right lymphatic duct > venous system
Where does lymph formation begin?
interstitial spsace of tissues with initial lymphatics/terminal lympatics/lymph capillaries
anchored by leaky endothelium (anchored to ECM by smll filaments)
terminal lymphatics coalesce into collecting vessels
Describe the leaky endothelium of terminal lymphatics.
anchored to ECM by small filaments
endothelial cells overlap creating 1-way valves
lack smooth muscle walls
Collecting vessels consist of ____.
lymphangions
possess 2-leaflet bicuspid valves, called “lymphatic hearts”, which contract regularly throughout lymphatic system and moving lymph in peristaltic waves
lymphangions
contain lymphangion
contain smooth muscle
extensive autonomic innervation
collecting vessels
collecting vessels prior to lymph node
afferent or prenodal vessels
collecting vessels draining lymph node
efferent or postnodal vessels
most highly organized lymphoid tissue
disperesed along course of lymph vessels
can be superficial or deep
lymphoid organs
functions of lymph nodes
filtration of lymp fluid
maturation of lymphochytes
phagocytosis of bacteria and cellular debris
path of lymph flow through a lymph node
afferent lymphatics > subscapular space > outer cortex > deep cortex > medullary sinus > efferent lymphatics
Where do lymphatic vessels drain into?
lymphatic trunk
drain lymph from lower limbs and pelvic organs
lumbar
drains abdominal viscera
intestinal
drains portions of thorax
bronchomediastinal
drains upper limbs
subclavian
drains portions of neck and head
jugular
located at level of L1-2
drains lymphatic trunks of lower body
gives rise to thoracic duct
cisterna chyli
origin of thoracic duct
cisterna chyli (dilation at L1-L2)
termination of thoracic duct
pierces Sibson’s fascia at superior inlet
U-turns to empty into L subclavian and L internal jugular veins
function of thoracic duct
master lymph vessel and drains:
- L head/neck
- LE
- L thorax/abdomen
- everything inferior to umbilicus
- receives from lumbar lymphatics
origin of right lymphatic duct
from junction of right angular and subclavian trunks (and occasionally bronchomediastinal trunk)
termination of right lymphatic duct
empties at right subclavian and right internal jugular venous junction
function of right lymphatic duct
drains:
- right head/neck
- RUE
- right thorax
- heart
- lungs (except LUL)
short course that originates at junction of R jugular and subclavian trunks (and occasionally the bronchomediastinal trunk) and ends where it empties at the junction of the right IJ and right subclavian vein
right lymphatic duct
acute signs of infectious lymph nodes
swollen, soft, painful
chronic signs of lymph node malignancy
swollen, indurated (hard), non-painful, fixed
left-supra clavicular node
Virchow’s Node
secondary syphilis node
epitrochlear node
spleen
liver
thymus
tonsils
appendix
visceral lymphoid tissue (GALT)
