The Lymphatic System

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Male External Genital Organs | Main Anatomy Index

Last updated 30 March 2006

The Lymphatic System

This page of notes is based purely on Dr. Ashwell's Lecture Summaries.

Click here to go to the lymphatics system notes under histology.

  1. Lymphatic vessels (or lymphatics);
  2. Lymphoid tissue, which consists of circulating lymphocytes as well as aggregates of lymphocytes and their associated cells.

 

The Functions of the Lymphatic System

  1. Transport of tissue fluid formed in the capillary bed;
  2. The removal by mononuclear phagocytic series cells of cell debris and foreign matter (e.g. bacteria) and the prevention of bacterial and foreign material from entering the blood stream;
  3. Production of lymphocytes and control of the immune responses.
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Lymphatic Vessels

 

The Flow of Lymph Fluid

  1. "Filtration pressure" in tissue spaces, generated by filtration of fluid under pressure from the haemal capillaries;
  2. Contraction of neighbouring muscles compresses the lymph vessels, moving lymph in the direction determined by the arrangement of valves;
  3. Pulsation of adjacent arteries;
  4. Respiratory movements and the low blood pressure in the brachiocephalic vein during inspiration.
  5. Smooth muscle in the walls of lymphatic trunks is most marked proximal to their valves. Stimulation of sympathetic nerves causes their contraction. Pulsatile contractions in the thoracic duct are known to occur also.
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Lymph Nodes

  1. Provision of a labyrinth of channels of large surface area and volume through which lymph slowly percolates;
  2. Trapping of foreign material in lymph nodes and exposure to nodal macrophages;
  3. Production of lymphocytes and a pool of stem cells to become antibody-producing B lymphocytes and mature T lymphocytes;
  4. Interaction between antigen-bearing mononuclear phagocytes and lymphocytes to produce immune responses;
  5. Re-entry of blood-borne lymphocytes into lymphatic channels and thence to the haemal circulation;
  6. Humoral antibody production and its addition to lymph and ultimately the blood.
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Major Lymphatic Channels

The Thoracic Duct

 

The Right Lymphatic Duct

  1. Lymph from the right head and neck, right arm is drained by the right jugular trunk;
  2. The right thorax is drained by the right subclavian trunk;
  3. The abdomen (down to the convex surface of the liver) is drained by the right bronchomediastinal trunk.
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Lymphatic Drainage of the Head and Neck

 

The Deep Cervical Lymphatic Nodes

 

Superficial Groups of Lymph Nodes

  1. In the head: occipital, retroauricular (mastoid), parotid, buccal (facial);
  2. In the neck: submandibular, submental, anterior cervical, superficial cervical.
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Lymphatic Drainage of the Thorax

  1. The left and right bronchomediastinal trunks drain into the thoracic duct and the right lymphatic duct respectively;
  1. Parietal nodes:
  1. Visceral nodes:

 

Lymphatic Drainage of the Abdomen and Pelvis

 

Preaortic Lymph Nodes

  1. Coeliac nodes, draining gastric, hepatic, pancreaticosplenic nodes;
  2. Superior mesenteric nodes, draining nodes in the mesenteries;
  3. Inferior mesenteric nodes, draining nodes in the mesenteries.

 

Lateral Aortic Lymph Nodes

  1. Kidney;
  2. Suprarenal glands;
  3. Abdominal ureter;
  4. Posterior abdominal wall;
  5. Testis and ovary;
  6. Uterus and uterine tube.
  1. Common iliac nodes;
  2. External iliac nodes;
  3. Internal iliac nodes.

 

Retroaortic Lymph Nodes

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The Thymus

 

The Tonsils and Waldeyer's Ring

 

The Spleen

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Michael Tam (c) 1998