Components of Lymphatic System
- Lymph
- Lymphatic vessels
- Lymphatic tissue
- Lymphatic nodules
- Lymph nodes
- Tonsils
- Spleen
- Thymus
Lymph
- Water plus solutes from two sources
○ Plasma - majority of lymph
○ Cells: hormones, enzymes, waste products- Returns to circulatory system via veins; essential for fluid balance.
Lymphatic Vessels
- Carry lymph away from tissues
- Have valves that ensure one-way flow
- heavenly fenestrated
Lymphatic capillaries
joins to form lymphatic vessels
○ More permeable than blood capillaries
○ Epithelium functions as series of one-way valves
○ Found in all parts of the body except nervous system, bone marrow, and tissues without Blood vessels (cartilage, cornea, epidermis)
Functions of the Lymphatic System
- Fluid balance
- Fat absorption
- Absorption of fat and other substances from digestive tract via lacteals. Fluid called chyme - Defense
Lymph Nodes
Clean the blood plasma
filter lymph
lymphatic trunk
takes clean lymph back to the ducts
Lymphatic Ducts
Drains lymph back into the blood
Right lymphatic duct = right side of head, right upper limb and right thorax
Thoracic Duct: remainder of the body
Lymphatic Unencapsulated
mucosa-associated lymphoid tissue (MALT). Found beneath epithelium as first line of attack against invaders.
Diffuse Lymphatic Tissue and Lymphatic Nodules
- Diffuse lymphatic tissue: dispersed lymphocytes, macrophages; blends with other tissues. Associated with other types of lymphatic tissue
- Lymphatic nodules: denser aggregations. Numerous in loose connective tissue of digestive (Peyer’s patches), respiratory, urinary, reproductive systems (MALT)
Lymph Nodes
Many Afferent and only one efferent vessel
Function: To clean lymph
Spleen
- Three path ways
○ Fast (most), slow, intermediate
○ Slow flow gets blood percolates through splenic cords- Functions
○ Destroys defective RBCs
○ Detects and responds to foreign substances
○ Limited reservoir for blood
- Functions
