The lymphatic system returns excess tissue fluid to the bloodstream via lymphatic vessels and lymph nodes. Its main functions are drainage of interstitial fluid and participation in the immune response. The immune system protects the body from foreign organisms through fighting infections and conferring immunity.

1. The Lymphatic and Immune Systems
• lymphatic vessels
• Lymphocytes
• lymphoid tissue
• lymphoid organs (spleen, lymph nodes, thymus)
function of the lymphatic system is to return excess tissue fluid back to
the blood vascular system.
The immune system protects our bodies from foreign organisms by
fighting infections and conferring immunity to disease.

2. • lymphatic capillaries
• lymphatic collecting vessels
• Lymph nodes
• lymph trunks
• lymph ducts

4. • lymphatic capillaries are absent from bone and teeth, from bone
marrow, and from the entire central nervous system, where
excess tissue fluid drains through the nervous tissue into the
cerebrospinal fluid. The cerebrospinal fluid then returns this
tissue fluid to the blood at the superior sagittal sinus.
• lymphatic capillaries, called lacteals, has a unique function.
Located in the villi of the mucosa of the small intestine, lacteals
absorb digested fats from the intestine, which causes the lymph
draining from the digestive viscera to become milky white.
• This fatty lymph is called chyle, and, like all lymph, it is carried to
the bloodstream.

5. Limph nodes:
• cervical nodes (head and neck)
• Axillary nodes (upper limbs)
• inguinal nodes (lower limbs)
• tracheobronchial nodes
(thoracic viscera)
• aortic nodes (posterior
abdominal wall)
• iliac nodes (pelvic organs and
lower limb)

6. 500 lymph nodes in the human body, ranging in diameter from 1 to 25 mm
Anatomy of lymph node
• Capsule
• Trabeculae
• afferent lymphatic vessels
• Hilum
• efferent lymphatic vessels
• lymph sinuses

7. Lymph Trunks
• Lumbar trunks (2) - along the sides of the aorta in the inferior abdomen,
receive all lymph from the lower limbs, the pelvic organs, anterior
abdominal wall.
• Intestinal trunk (1) -lies near the posterior abdominal wall in the
midline, receives fatty lymph (chyle) from the stomach, intestines, and
other digestive organs.
• Bronchomediastinal trunks (2) - Ascending near the sides of the
trachea, collect lymph from the thoracic viscera and thoracic wall.
• Subclavian trunks (2) near the base of the neck, these paired trunks
receive lymph from the upper limbs; they also drain the inferior neck
and the superior thoracic wall.
• Jugular trunks (2) - Located at the base of each internal jugular vein,
these paired trunks drain lymph from the head and neck.

8. lymph ducts:
 Thoracic duct
 Right lymphatic duct

15. Edema of the arm and forearm often follows a mastectomy