ANATOMY OF LYMPHATIC SYSTEMMario Makarević2nd year2013/2014Mentor: A. Žmegač Horvat

Lymph• fluid similar to blood plasma• no erythrocytes or platelets• less proteins• more leukocytes

• filters out of blood vessels• lymph capillaries collect interstitial fluid

Composition• lymphatic vessels• lymphatic organs• lymphatic tissue

Lymphatic vessels• lymph capillary• single layer of overlapping endothelial cells• blind end• absent from brain, spinal cord, splenic pulp, bone marrow• located next to blood capillaries in tissue spaces

Lymphatic vessels• lymph vessels• afferent and efferent• three-layered wall thinner than

vein• semilunar valves, contractile

lymphangion

Lymphatic vessels• lymph trunks• confluence of many efferent lymph vessels

• jugular lymph trunks• subclavian lymph trunks• bronchomediastinal lymph trunks• lumbar lymph trunks• intestinal lymph trunk—unpaired

Lymphatic vessels• lymph ducts• right lymphatic duct and thoracic duct• return fluid to blood

• right lymphatic duct• about 1.5 cm in length• right venous angle• lymph from right half of head, neck,

thorax and right upper limb

• thoracic duct• about 38-45 cm in length

• > front of L1 as cisterna chyli – emulsified fats and free fatty acids absorbed by lacteals

• > aortic hiatus of the diaphragm • > ascends along on the front of the vertebral

column, between thoracic aorta and azygos vein

• > left venous angle

Lymph nodes• collections of stationary lymph tissue • from a few millimeters to about 1–2 cm long• fibrous capsule• afferent lymph vessels entering at the periphery, efferent

lymph vessels emerging at the hilum• cortex and medulla

Cortex• outer region directly beneath capsule• densely packed lymphocytes (B-cells) arranged in follicles –

germinal center when challenged with an antigen• deeper cortex – T-cells• subcapsular sinus drains into trabecular

Medulla• inner region• strands called medullary cords – B-cells, macrophages and

plasma cells• large blood vessels• medullary sinuses

Major sites of lymph node concentration• cervical – head and neck• axillary – hand, arm and breast• mediastinal – abdominal cavity• inguinal – lower extremities and external genital organs

Diffuse lymphatic tissue• not enclosed by a capsule• reticular connective tissue with lymphatic nodules• almost every organ, lamina propria of mucous membranes• tonsils, Peyer’s patches, appendix

Lymph circulation• must be returned to blood stream to maintain blood volume

and pressure• antibodies, lymphocytes, and monocytes• obstruction leads to edema

Lymph circulation• no central pump• slow movement• lymph is kept moving by:• contraction of adjacent skeletal muscle and arterial pulsation• contraction of smooth muscles – peristalsis

Metastasis• bacteria or body cells spread from one body part to another• breast cancer to axillary nodes• chemotherapy

Sources• http://www.innerbody.com/image/lympov.html• http://en.wikipedia.org/wiki/Lymphatic_system• https://www.boundless.com/physiology/the-lymphatic-

system/• http://www.cea1.com/anatomy-sistems/lymph-capillaries/