1. Lymphatic System

2. Lymphatic System Consists of: Lymphatic vessels Lymphatic tissues
Lymphoid organs
Lymph which consists of
Interstitial fluid
Lymphocytes
Macrophages

3. Lymphatic System

5. Functions of the Lymphatic System
Production, maintenance, distribution of lymphocytes
Lymphocytes are infection fighting WBC
Maintain normal blood volume
Return of water and solutes that leak out into the interstitial fluid to the circulatory system
Plasma protein recycling
Alternate route for transport of hormones, nutrients, and waste products

6. Lymphoid Structures Primary lymphoid structures
Structures that produces lymphocytes
Bone marrow, thymus, spleen
Secondary lymphoid structures
Places where the immune response begins
Lymph nodes, tonsils

7. Lymphatic capillaries

9. Lymphatic Vessels Carry lymph from peripheral tissue to venous system
Like veins, they go from small to large and have valves
System has no pump, and is unidirectional
Vessel system goes as follows:
Lymph capillaries
Lymph collecting vessels
Lymph nodes
Lymph trunks
Lymph ducts

10. Lymph Ducts Lymph trunks empty into the lymph ducts
Lumbar trunk
Intestinal trunk
Bronchomediastinal trunk
Subclavian trunk
Jugular trunk
Two major lymph ducts
Thoracic duct
Right lymphatic duct
Ducts return lymph to venous circulation at the L and R subclavian veins

12. Lymph and Disease
Any materials in the interstitial fluid can be picked up by the lymphatic system
Pathogens in the tissues can get into the lymph and travel throughout the body
Lymph nodes “inspect” the lymph for foreign material
Swollen or tender nodes can indicate an immune response to pathogens in the lymph

13. This looks bad! Elephantiasis
Blockage of the lymphatic return system by a worm
Causes gross swelling(edema) of the tissue due to fluid build up
Can be cured
Don’t worry the worm doesn’t live in San Diego

14. Lymphocytes Lymphocytes are types of WBC
Responsible for specific immunity to pathogens
Two major types of lymphocytes
B cells: produce antibody for humoral immune response
T cells: cell-mediated immunity
T helper cells, cytotoxic T cells, and suppressor T cells are the major types

15. Origin of B cells and T cells
Both types of cells originate in the bone marrow
B cells mature in the bone marrow hence the name B cells
T cells originate in the bone marrow but move to the thymus gland to mature, hence the name T cells
Both T cells and B cells are found in various lymphatic tissues

16. Lymphoid tissue and organs
Tonsils
Lymph nodes
Spleen
Thymus

17. Tonsils Lymphoid nodules found in the pharynx
Aggregation of lymphocytes that remove pathogen from air or food
Usually 5 tonsils
Single pharyngeal tonsil (adenoids)
Pair of palatine tonsils
Pair of lingual tonsils

19. Lymph Node

20. Lymph Node

25. Spleen
Soft, pulpy organ wedged between the stomach, diaphragm and left kidney
The cellular component of the spleen is called the pulp
Red pulp
Mostly RBC
White pulp
Lymphatic nodules