Lymphatic System and Immunity
What is lymph?
Fluid inside lymphatic vessels.
Where does lymph come from?
It enters lymphatic vessels from interstitial fluid. Interstitial fluid is a filtrate of blood plasma.
Two lymphatic ducts
Right Lymphatic Duct
Thoracic Duct
Five types of Trunks
Lumbar Trunks
Intestinal Trunk
Bronchomediastinal Trunk
Subclavian Trunk
Jugular Trunk
Where does the lumbar trunk gather lymphatic fluid from?
Pelvis and Legs
Where does the intestinal trunk gather lymphatic fluid from?
Abdomen
Where does the Bronchomediastinal trunk gather lymphatic fluid from?
Right and Left Thorax
Where does the subclavian trunk gather lymphatic fluid from?
Right and Left shoulder and arm
Where does the jugular trunk gather lymphatic fluid from?
Right and Left head and neck
What's trunks deliver to the right lymphatic duct?
Right Jugular Trunk
Right Subclavian Trunk
Right Bronchomediastinal Trunk
What's trunks deliver to the Thoracic Duct?
Left Jugular Trunk
Left Subclavian Trunk
Left Bronchomediastinal Trunk
Right and Left Lumbar Trunk
Intestinal Trunk
Macrophages
Engulf and destroy
Pathogens
Disease causing micro organisms
Where is the spleen located?
Upper left abdominal cavity
What do lymphatic trunks do?
Drain lymph from the body
What do T cells and B cells protect against?
Antigens of foreign pathogens.
Bacteria and their toxins; viruses
mismatched RBCs or cancer cells
T Cells
Manage the immune response.
Attack and destroy foreign cells
B Cells
Produce plasma cells, which secrete antibodies
T cells (T lymphocytes) differentiate...
Thymus Gland
B cells (B lymphocytes) differentiate...
Red Bone Marrow
Macrophages
phagocytize foreign substances and help activate T cells
Dendritic cells
Capture antigens and deliver them to lymph nodes
Reticular cells
Produce reticular fibers that support lymphoid organs
White pulp
One of two distinct areas in the spleen around central arteries. Mostly lymphocytes on reticular fibers and involved in immune functions.
Red pulp
One of two distinct areas in the spleen. In venous sinuses and splenic cords. Rich in RBCs macrophages for disposal of worn-out RBCs and blood-borne.
Palatine Tonsils
Posterior end of the oral cavity
Lingual Tonsils
Grouped at the base of the tongue
Pharyngeal Tonsil
Posterior wall of the nasopharynx
Tonsillar Crypts
Overlying epithelium in the tonsils that traps and destroys bacteria and particulate matter.
Produces and stores lymphocytes
Peyer’s Patches
Clusters of lymphoid follicles in the wall of the distal portion of the small intestine
Peyer’s Patches and the Appendix
Destroy bacteria, preventing them from breaching the intestinal wall. Generate “memory” lymphocytes
Lymphatic Follicles
Type of lymphoid tissue, solid, spherical bodies of tightly packed reticular elements and cells
Germinal center composed of dendritic and B cells
May form part of larger lymphoid organs
Diffuse Lymphatic Tissue
Type of lymphoid tissue comprises of scattered reticular tissue elements in every body organ
Larger collections in the lamina propria of mucous membranes and lymphoid organs
Lymph is propelled by the same forces that assist venous return
Skeletal muscle pumps
Respiratory pumps
Valves to prevent backflow
Vasoconstriction and vasodilation of smooth muscle in walls of lymphatic vessels
Lymphocytes main warriors of the immune system
Two Main Varieties
T cells (T lymphocytes)
B cells (B lymphocytes)
Empties lymph into venous circulation at the junction of the internal jugular and subclavian veins on its own side of the body
Ducts
Right lymphatic Duct
Drains the right upper arm and the right side of the head and thorax
Thoracic Duct
Arises from the cisterna chyli and drains the rest of the body
How do Lymphatic collecting vessels differ from veins?
Have thinner walls, with more internal valves
Anastomose more frequently
Collecting vessels in the skin travel with superficial veins
Deep vessels travel with arteries
Lacteals
Specialized lymph capillaries present in intestinal mucosa. That absorb digested fat and deliver fatty lymph (chyle) to the blood
How do pathogens travel throughout the body
lymphatics
Lymph Nodes
Principal lymphoid organs of body
Germinal center
Part of Composed of dendritic and B cells. May form part of larger lymphoid organs
Embedded in connective tissue, in clusters along lymphatic vessels. Near the body surface in inguinal, axillary, and cervical regions of the body
Lymph Nodes
Spleen
Functions:
Site of lymphocyte proliferation and immune surveillance and response
Cleanses the blood of aged cells and platelets and macrophages remove debris
Stores breakdown products of RBCs (e.g., iron) for later reuse
Stores blood platelets and monocytes
Site of fetal erythrocyte production (normally ceases after birth)
Largest lymphoid organ. Served by splenic artery and vein, which enter and exit at the hilum
Spleen
Entry of lymph in to the lymphatic capillaries is promoted by?
one-way mini valves
Circulation of lymph in the lymph nodes
What allows Lymphocytes and macrophages time to carry out functions?
Fewer efferent vessels, causing flow of lymph to stagnate
Where does the left and right lumbar trunk drain before the thoracic duct?
Cisterna Chyli
What trunk drains into the Cisterna Chyli first?
Intestinal Trunk
When B lymphocytes are dividing rapidly, what lymphoid tissue enlarges?
Germinal Center
Trabeculae are extensions of
The capsule
Lymph sinuses
Large lymph capillaries in a lymph node spanned by crisscrossing reticular fibers
Areas of lymphocytes suspended by reticular fibers in the spleen are known as
White pulp