Treatment for cancer documents, Cheat Sheet of Private law

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Lymphatic system

LYMPH

• Lymph is a clear watery fluid that circulates

through the lymphatic vessels.

• Once the interstitial fluid drains into the

lymphatic vessels, it is called lymph. So

lymph is identical in composition to

interstitial fluid.

LYMPH VESSELS

• Lymph vessels are thin walled, valved structures

that carry lymph.

• Lymphatic vessels begin as lymphatic capillaries,

which join up to form lymphatic vessels.

• Larger lymphatic vessels unite to form lymphatic

trunk.

• Lymphatic trunk opens into two large lymphatic

duct – right lymphatic duct and thoracic (left

lymphatic)duct.

• In small intestine, specialized lymphatic

capillaries called lacteals absorb dietary

lipids into lymphatic vessels and ultimately

into the blood. The presence of these lipids

causes the lymph draining from the small

intestine to appear creamy white. Such

lymph is referred to as chyle.

• Tissues that lack lymphatic capillaries

include avascular tissues (such as cartilage,

the epidermis, and the cornea of the eye),

the central nervous system, bones, teeth,

portions of the spleen, and red bone

marrow.

Lymphatic vessels

• Structure similar as veins.
• Thin walls and more valves.
• 3 tunica layers – intima, media and adventitia. Tunica intima, the inner layer is made up of single flattened simple squamous epithelium composed of epithelium called endothelium, and the cells are called endothelial cells. The middle tunica media is of smooth muscles and elastic tissue that are arranged in a circular fashion around the endothelium. The outermost adventitia consists of fibrous tissue.
• Afferent lymphatic vessels – the vessel that enters

lymph node.

• Efferent lymphatic vessel – the vessel that leaves

lymph node.

Lymphatic duct

• Thoracic duct
• Right lymphatic duct

Thoracic duct / Left lymphatic duct

• Main duct for the return of lymph to blood.
• 38 – 45 cm length.
• Begins at cisterna chyli (anterior to 2 nd

lumbar

vertebrae).

• Cisterna chyli is an enlarged lymph sac which

receives lymph from right and left lumbar trunks

and intestinal trunk.

• Receives lymph from cisterna chyli, left jugular, left

subclavian, and left bronchomediastinal trunks.

• The thoracic duct drains lymph into venous blood at

the junction of the left internal jugular and left

subclavian veins.

Right lymphatic duct

• About 1.2 cm length.
• Receives lymph from the right jugular, right

subclavian, and right bronchomediastinal

trunks.

• Drains into venous blood at the junction of

the right internal jugular and right

subclavian veins.

Lymph Node Structure  Bean or kidney-shaped.  1 – 25 mm length.  Covered by capsule.  Capsule is composed of connective tissue.  Trabeculae , the capsular extensions divide the node into compartments which provide a route for blood vessels into the interior of a node.  Internal to the capsule is a supporting network of reticular fibers and fibroblasts.  The capsule, trabeculae, reticular fibers, and fibroblasts constitute the stroma of a lymph node.

• Subcapsular sinus is the space between capsule and cortex.
• The lymph node is divided into
  • superficial cortex
  • deep medulla
• Cortex is the portion beneath subcapsular sinus.
• Cortex consists
  • outer cortex
  • inner cortex
• Outer cortex contain
  • Lymphatic nodules
  • Germinal center
• Lymphatic nodules (follicles)are egg- shaped aggregates of B cells in outer cortex - Primary lymphatic nodule - Secondary lymphatic nodules