Chapter 20: Lymphatic system Flashcards
(45 cards)
What are the general functions of the lymphatic system?
Return interstitial fluid and leaked proteins that are leaked out in the capillaries back to the cardiovascular system
Acts as the structural basis of the immune system
What is the fluid inside the lymphatic system called?
lymph
Where does the lymphatic system return the collected fluid?
to the venous system near the heart
Where are lymphatic capillaries not found in the body?
teeth, bones, marrow, and CNS
What are the two structural modifications in lymph capillaries that make them so much more permeable then vascular capillaries?
Cells of the endothelium overlap in such a way that they form one way, flap-like mini valves that open/close in response to pressure.
Collagen fibers secure them to their environment so that when interstitial pressure increases, it does not collapse.
What are lacteals and where are they found?
specialized lymph capillaries that absorb digested fats and deliver fatty lymph called CHYLE to the blood
villi of the small intestine
What is CHYLE?
fatty lymph found in the lacteals
What can be said about the general structure of the collecting vessels in the lymphatic system?
run parallel to blood vessels
walls are like veins
more valves and anastomoses
nutrients are provided by VASA VASORUM
vessels join to form lymphatic trunks
formed by joining lymph capillaries
What are the 7 major trunks of the lymphatic system?
R & L LUMBAR TRUNKS: drain legs
INTESTINAL TRUNK
R & L BRONCHOMEDIASTINALS, SUBCLAVIANS, JUGULARS: drain upper body and head
What are the two ducts in the lymphatic system?
RIGHT LYMPHATIC DUCT: drains lymph from right upper arm and right side of the head and thorax
THORACIC DUCT: receives lymph from the rest of the body
What is the cisterna chyli?
a sac like structure that collects lymph from the lumbar and intestinal trunks
marks the start of the thoracic duct
Where does the right lymphatic duct drain into?
junction of right internal jugular and subclavian vein
Where does the thoracic duct drain into?
junction of left internal jugular and subclavian vein
What is the rate of lymph transport?
3L / 24 hrs
How does the rate of lymph transport compare to that of veinous blood return?
slower
what does the movement of lymph depend on?
contraction of skeletal and respiratory muscles
pulsations of nearby arteries
contraction of smooth muscle in walls of trunks and thoracic duct
What is the condition known as LYMPHEDEMA?
swelling that results from blockage of lymph flow resulting in lymph accumulating distally from the blockage.
what are the 4 types of cells in the lymphoid system?
LYMPHOCYTES
MACROPHAGES
DENDRITIC CELLS
RETICULAR CELLS
What are the two sub-categories of lymphocytes? describe the role of each.
B CELLS: mature in the bone marrow and produce antibodies
T CELLS: mature in thymus and manage immune response. Some can attack and destroy infected/mutant cells directly. constantly patrol the blood, lymph, and lymph nodes
What are macrophages?
Strong phagocytes that destroy foreign antigens and help activate t cells
What are dendritic cells?
function as an early warning system that activate defense system by capturing antigens and delivering them to lymph nodes
What do reticular cells do in the lymph system?
form internal skeleton of lymphoid organs and tissue
produce the stroma that supports other cells
What is lymphoid tissue made of and what role does this play in the lymphatic system?
reticular connective tissue
- sites for lymphocyte reproduction
- sites for surveillance
- quick travel
What are the two types of lymphoid tissue?
DIFFUSE TISSUE
LYMPHOID FOLLICLES
