Chapter 20- Lymphatic System Flashcards
Lymphatic system
picks up fluid lost by blood capillaries
Consists of lymph vessels, lymph, and lymph nodes
Fluid that is picked up by lymph capillaries is eventually returned to circulation
Lymphoid organs
provide structural basis for immune system
Monitors body for infection
House phagocytic cells and lymphocytes
Lymph
Fluid found in the lymph vessel
Lymphatic vessels
picks up protein-containing interstitial fluid that is not reabsorbed by blood capillaries
Only move fluid towards the heart
Lymph capillaries
blind-ended vessels that weave through capillary beds
Anchoring filaments
increase in interstitial fluid pulls on anchoring filaments
Flaps of endothelial wall open easily
Anchor is like a rope that opens the flap allowing fluid in
Lacteals
Specialized lymph capillaries for movement of fats from small intestine of bloodstream
Only found around small intestine
Allow for absorption of fats
Collecting Lymphatic Vessels
In skin—vessels travel with superficial veins
In trunk-–vessels travel with deep arteries
Lymphatic trunks
drainage areas resulting from collecting vessels uniting
Lumbar trunk (2): drains lower extremities (legs)
Bronchomediastinal trunk (2): drains thorax
Subclavian trunk (2): drains upper extremities (arms) & superficial thoracic wall
Jugular trunks (2): drains head & neck
Intestinal trunk (1): drains digestive organs
Lacteals and the draining of fats
Lymphatic ducts
structures that lymphatic trunks drain into
Both ducts empty into junction at internal jugular vein & subclavian vein
Right lymphatic duct empties into veins on right side
Thoracic duct empties into veins on left side
Right lymphatic duct
drains lymph from right upper limb, right side of head, and right thorax
Thoracic duct
drains any part of body that is not drained by right lymphatic duct
Usually begins at cisterna chyli
Left upper limb, left side of brain, left side of thorax
Both lumbar trunks (right & left limbs)
Intestinal trunk
Cisterna chyli
Where the thoracic duct begins
Solutions to transporting lymph
1) Smooth muscle in larger vessel walls helps push lymph through
2) Similar to circulation in veins: valves to prevent backflow, respiratory pump
3) Circulation also improved by pulsatile nature of nearby arteries
4) Physical movement (skeletal muscle) is important for increasing lymph flow**
For infected regions → body part should be mobilized to increase rate of removal of inflammatory material
helper T cell
manages/mediates immune response
Assist in maturation of B cells, macrophages, and other immunity-related cells
Attacking what they need to attack and not going overboard
Killer T Cell
cell destroyer
Kill off virus-infected and cancerous cells
B Cells
produce plasma cells, which secrete antibodies into blood
Antibodies put a “red flag” on foreign antigen cells → marked for destruction
Helps them recognize what does and doesn’t belong
Macrophages (Defense cell)
phagocytize large, foreign substances & help activate T cells
Dendritic cells (Defense cell)
cells that escort “red flagged” cells back to lymph nodes
Dendritic cells put flagged cells on display → other immune cells know to destroy
Holds the cell up and displays it to other immune system cells
Reticular cells (Supporting cell)
Produce stroma → supports cell types in lymphoid tissue/organs
No immune system functioning at all
reticular connective tissue
Exception: not in thymus
Loose connective tissue
Diffuse lymphoid tissue
Loose aggregation of lymphoid cells and reticular fibers
Present in most organs of the body
Larger collections found in mucous membranes
Mucous membranes- leading to the exterior - mouth
In immediate contact with the external environment - microorganisms and external environment can impact the lymph nodes