1. Structure and Functions of the Lymphatic System

2. Functions of the Lymphatic System
Fluid balance
When blood moves through the capillaries fluid from the blood plasma leaks into the interstitial spaces
Lymphatic capillaries around the blood capillaries absorb this excess fluid and bring it back to the blood
Fat absorption
Lymphatic capillaries line the small intestine and absorb fat which is then transferred to the blood
Defense
Pathogens are filtered from lymph nodes and the spleen

3. Types of Lymphatic Tissue
Diffuse Lymphatic Tissue:
Dispersed tissue that contains immune cells
Found around the lymphatic nodules
Lymphatic Nodules:
Dense tissue arranged into a compact, spherical structure
Found within the lymph nodes and the spleen

4. Lymphatic Vessels Carry lymph from the tissues to the bloodstream
Contain one way valves that push the lymph within them to the bloodstream with the help of surrounding muscles

5. Lymph Nodes Small, round disks throughout the lymphatic vessels
Filter lymph and remove pathogens
Contain Germinal Centers which are site of lymphocyte production

6. External Lymph Node Structure
Capsule: Protective covering on the outside with extensions called trabecula that divide the lymph node into sections
Afferent Lymphatic Vessels: Carry lymph to the node
Efferent Lymphatic Vessels: Carry lymph away from the node

7. Inner Lymph Node Structure
Cortex: outer sections made up of lymphatic nodules, germinal centers, diffuse lymphatic tissue, and lymphatic sinuses
Sinus = space between tissues
Medulla: inner section made up of diffuse lymphatic tissue and lymphatic sinuses

8. Lymph Nodes Location
Lymph nodes are found all around your body, but they are concentrated in areas where pathogens are most likely to enter the body
Ex: Digestive System, Lungs, Reproductive System

9. Lymph Movement
Lymph is moved through the lymph vessels towards the thoracic duct and right lymphatic duct which dump the lymph into the subclavian veins
system/lecture/Lymphatic-System- Animation/?referrer=concept_details

10. Tonsils
Groups of lymph nodes and lymph tissue that protects the pharynx against harmful substances and bacteria

11. Spleen
Has a capsule and trabeculae on the outside with white pulp and red pulp inside
White Pulp: produces white blood cells and makes antibodies
Red Pulp: filters antigens, microorganisms, and defective/old red blood cells out of the blood
Blood moves through the Splenic Artery → White Pulp → Red Pulp → Splenic Veins

12. Thymus
Where T Cells that are made from stem cells in the red bone marrow come to mature